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[CLJ-1965] clojure.spec/def should support an optional doc-string Created: 19/Jun/16  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: Release 1.10

Type: Feature Priority: Minor
Reporter: Alexander Kiel Assignee: Unassigned
Resolution: Unresolved Votes: 51
Labels: spec

Approval: Vetted

 Description   

Like clojure.core/def clojure.spec/def should support an optional doc string because one usually likes to describe specs in more detail as one could through keyword naming.



 Comments   
Comment by Moritz Heidkamp [ 03/Nov/16 4:23 PM ]

Building on this idea, I suggest to add first-class metadata support to registered specs and implement doc strings in terms of that (i.e. the same way as with vars).

Comment by Josh Brandoff [ 01/Apr/17 5:02 PM ]

Hi! Was just discussing the potential for a feature like this with a colleague. What's the current status? Was thinking of potentially working on it but wanted to get feedback and guidance from the community first.

Comment by Alex Miller [ 03/Apr/17 9:32 AM ]

We don't have a recommended approach to this yet so not looking for a patch at this time.





[CLJ-1959] adding functions `map-vals` and `map-keys` Created: 14/Jun/16  Updated: 17/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Hiroyuki Fudaba Assignee: Unassigned
Resolution: Unresolved Votes: 42
Labels: None

Attachments: Text File map-mapper.patch     Text File map-mapper-v2.patch     Text File map-mapper-v3.patch    
Approval: Triaged

 Description   

Many people have been writing a function to map values in HashMap:

Proposal: Add `map-keys` and `map-values` which: maps keys in HashMap, and map values in HashMap. They return HashMap as a result.

Workaround: Using function `reduce-kv` or ordinary `map` and `into` is a common solution, but they are confusing and types change, which makes it tricky and tedious.

Discussions: https://groups.google.com/forum/#!topic/clojure-dev/kkPYIl5qj0o



 Comments   
Comment by Hiroyuki Fudaba [ 14/Jun/16 11:22 AM ]

code and test for map-keys and map-vals

Comment by Nicola Mometto [ 14/Jun/16 1:05 PM ]

I propose those functions being called `update-vals` and `update-keys` rather than `map-vals` and `map-keys`

Comment by Alex Miller [ 14/Jun/16 2:03 PM ]

It's not worth bike-shedding names on this - Rich will have his own opinion regardless.

On the patch:

  • remove the :static metadata, that's not used anymore
  • needs docstrings, which should be written in the style of other Clojure docstrings. map is probably a good place to draw from.
  • rather than declare into, defer the definition of these till whatever it needs has been defined. There is no reason to add more declares for this.

There are other potential implementations - these should be implemented and compared for performance across a range of input sizes. In addition to the current approach, I would investigate:

  • reduce-kv with construction into a transient map. This allows the map to reduce itself (no seq caching needed) and avoid creating entries only to tear them apart again.
  • transducers with (into {} (map ...) m)

Also should consider

  • whether to build a k/v vector and convert to a map, or build a map directly (the former may be faster, not sure)
  • if building the map, how to construct the map entries (vector vs creating a mapentry object directly)
  • in map-keys, is there any open question when map generates new overlapping keys?
  • are there places in existing core code where map-keys/map-vals could be used (I am pretty certain there are)
Comment by Hiroyuki Fudaba [ 15/Jun/16 11:01 AM ]

Thanks for comments

> I propose those functions being called `update-vals` and `update-keys` rather than `map-vals` and `map-keys`
Maybe. But I name it `map-*` just for now, we can choose it later

about potential implementations:
I have tried several implementations, and seems to be the current implementation is the fastest.
You can see it here: https://github.com/delihiros/performance

about considerings:
> whether to build a k/v vector and convert to a map, or build a map directly (the former may be faster, not sure)
> are there places in existing core code where map-keys/map-vals could be used (I am pretty certain there are)
> if building the map, how to construct the map entries (vector vs creating a mapentry object directly)
I'll check which them as soon as possible. I haven't done it yet.

> in map-keys, is there any open question when map generates new overlapping keys?
I believe it should be overwritten by latter applied key and value.

Comment by Nathan Marz [ 15/Jun/16 11:35 AM ]

I've done quite a bit of investigation into this through building Specter. Here are some benchmarks of numerous ways of doing map-vals, including using Specter.

Code: https://github.com/nathanmarz/specter/blob/4778500e0370fb211f47ebf4d69ca64366117b6c/scripts/benchmarks.clj#L87
Results: https://gist.github.com/nathanmarz/bf571c9ed86bfad09816e17b9b6e59e3

A few comments:

  • Implementations that build and tear apart MapEntry's perform much worse.
  • Transients should be used for large maps but not for small ones.
  • This benchmark shows that the property of maintaining the type of the map in the output can be achieved without sacrificing performance (the test cases using Specter or "empty" have this property).
Comment by Hiroyuki Fudaba [ 11/Jul/16 3:27 AM ]

I've modified the implementation. It should be faster than before.

Comment by Steve Miner [ 20/Jul/16 10:46 AM ]

Implementations that call reduce-kv are not lazy so the documentation should be clarified in the proposed patch (map-mapper-v3.patch). Also, it's probably better to say "map" (as the noun) rather than to specify a particular concrete type "hash map".

Comment by Nicola Mometto [ 21/Jul/16 4:30 AM ]

map->map operations can't be lazy either way. Even if one implementation used lazy operations to iterate over the original map, the `into {}` would realize it later.

Comment by Nathan Marz [ 14/Nov/17 2:15 PM ]

-1 to this. Clojure aims to be a small core, pushing additional functionality into libraries. The problem space of compound transformations, of which this functionality is a small piece, is already thoroughly solved by Specter. Specter's `MAP-VALS` and `MAP-KEYS` navigators additionally support removal of key/value pairs during transformation by transforming to special `NONE` value. This expands the utility greatly.

Also worth noting is a fast implementation requires a totally different approach depending on the type of the map. `reduce-kv` with transients is optimal for hash maps, but for array maps using lower level facilities provide ~60% speed boost. See Specter's implementation here https://github.com/nathanmarz/specter/blob/1.0.4/src/clj/com/rpl/specter/navs.cljc#L243

Comment by Ghadi Shayban [ 14/Nov/17 4:40 PM ]

Nathan you're making a strawman re: compound transformations. This isn't a request for a function with filtering knobs or conditional behavior (which Clojure has historically opposed). There are other valid approaches than Specter's.

Re fast implementation: Not every function has to strive for the most performant implementation, esp at the cost of branching and general complexity. A cost model for performance has to take into account complexity.

This ticket is a request for a convenience that is repeated in many codebases.

Do we want to preserve metadata? Many map operations do.
Do we want to assume IEditableCollection?

Comment by Nathan Marz [ 14/Nov/17 8:57 PM ]

Performance is incredibly important for general data structure manipulation functions like this. Manipulating data structures is one of the most basic things you do in a language, and it's done all the time in performance sensitive code. Having to abandon the "nice" functions for ugly specialized code in performance sensitive code is a failure of the language.

`map-vals`/`map-keys` are part of a rich problem space of which myself and the users of Specter have learned a lot the past few years. Clojure barely touches this problem space, especially when it comes to nested or recursive data structures. Adding functions to Clojure that are significantly inferior in both semantics and performance to what already exists in an external library seems pretty silly to me. Just my two cents.

Comment by Hiroyuki Fudaba [ 17/Nov/17 6:48 AM ]

I agree with Nathan Martz that the performance is very important, but I still have a strong opinion that this function should be somehow imported to the core part of the language.
People use this transformation pretty often and if there is a fast implementation in the core it will be a great benefit to all of us.





[CLJ-2116] Support for selective conforming with clojure.spec Created: 22/Feb/17  Updated: 31/Oct/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Tommi Reiman Assignee: Unassigned
Resolution: Unresolved Votes: 27
Labels: spec
Environment:

[org.clojure/clojure "1.9.0-alpha14"]


Attachments: Text File clj-2116.patch    

 Description   

Problem

using clojure.spec in runtime border validation supporting multiple exchange formats is hard.

Details

Currently in clojure.spec (alpha-14), conformers are attached to Spec instances at creation time and they are invoked on every conform. This is not very useful in system border validation, where conforming/coercion functions should be selected based on runtime data, e.g. the exchange format.

Examples:

  • a keyword? spec:
    • with EDN, no coercion should be done (it can present Keywords)
    • with JSON, String->Keyword coercion should be applied
    • with String-based formats (CSV, query-params, ...), String->Keyword coercion should be applied
  • a integer? spec:
    • with EDN, no coercion should be done (it can present numbers)
    • with JSON, no coercion should be done (it can present numbers)
    • with String-based formats (CSV, query-params, ...), String->Long coercion should be applied

Here is a more complete example:

(s/def ::id integer?)
(s/def ::name string?)
(s/def ::title keyword?)
(s/def ::person (s/keys :opt [::id], :req-un [::name ::title]))

;; this is how we see the data over different exchange formats
(def edn-person {::id 1, :name "Tiina", :title :boss})
(def json-person {::id 1, :name "Tiina", :title "boss"})
(def string-person {::id "1", :name "Tiina", :title "boss"})

;; here's what we want
(def conformed-person edn-person)

To use this today, one needs to manually create new border specs with different conformers for all different exchange formats. Non-qualified keywords could be mapped in s/keys to work (e.g. ::title => ::title$JSON), but this wont work if fully qualified keys are exposed over the border (like ::id in the example) - one can't register multiple, differently conforming version of the spec with same name.

Suggestion

Support selective conforming in the Spec Protocol with a new 3-arity conform* and clojure.spec/conform, both taking a extra user-provided callback/visitor function. If the callback is provided, it's called from within the Specs conform* with the current spec as argument and it will return either nil or a 2-arity conformer function that should be used for the actual confrom.

Actual conforming-matcher implementations can be maintained in 3rd party libraries, like spec-tools[1].

Using it would look like this:

;; edn
(assert (= conformed-person (s/conform ::person edn-person)))
(assert (= conformed-person (s/conform ::person edn-person nil)))

;; json
(assert (= conformed-person (s/conform ::person json-person json-conforming-matcher)))

;; string
(assert (= conformed-person (s/conform ::person string-person string-conforming-matcher)))

Alternative

Another option to support this would be to allow Specs to be extended with Protocols. 3rd party libs could have a new Conforming protocol with 3-arity conform and add implementations for it on all current specs. Currently this is not possible.

[1] https://github.com/metosin/spec-tools



 Comments   
Comment by Alex Miller [ 22/Feb/17 3:33 PM ]

I don't think we are interested in turning spec into a transformation engine via conformers, so I suspect we are probably not interested. However, I'll leave it for Rich to assess.

Comment by Tommi Reiman [ 23/Feb/17 1:26 AM ]

Currently, Plumatic Schema is the tool used at the borders. Now, people are starting to move to Spec and it would really bad for the Clojure Web Developement Story if one had to use two different modelling libraries for their apps. If Spec doesn't want to be a tranformation engine via conformers, I hope for the Alternative suggestion to allow 3rd parties to write this kind of extensions: exposing Specs as Records/Types instead of reified protocols would do the job?

Comment by ken restivo [ 28/Feb/17 9:43 PM ]

I could see why the Clojure core developers might not want Spec to support this kind of coercion, but the practical reality is that someone will have to. If it isn't in Spec itself, it'll have to be done libraries built upon it like Tommi's.

The use case here is: I have a conf file that is YAML. I'm parsing the YAML using a Clojure library, turning it into a map. Now I have to validate the map, but YAML doesn't support keywords, for example, and the settings structure goes directly into Component/Mount/etc as part of the app state, so it makes sense to run s/conform on it as the first step in app startup after reading configuration. Add to this the possibility of other methods of merging in configuration (env vars, .properties files, etc) and this coercion will be necessary somewhere.

Comment by Tommi Reiman [ 08/May/17 1:03 PM ]

Any news on assessing this? I would be happy to provide a patch or a link to a modified clojure.spec with samples on usage with the 3-arity conform in it. Some thinking aloud: http://www.metosin.fi/blog/clojure-spec-as-a-runtime-transformation-engine/

Comment by Alex Miller [ 09/May/17 10:10 AM ]

Rich hasn't looked at it yet. My guess is still that we're not interested in this change. While I think some interesting problems are described in the post, I don't agree with most of the approaches being taken there.

Comment by Simon Belak [ 10/May/17 4:39 AM ]

Why not just use s/or (or s/alt) and then dispatch on the tag. Something like:

(s/def ::id (s/and (s/or :int integer?
                         :str string?)
                   (s/conformer (fn [[tag x]]
                                  (case tag
                                    :int x
                                    :str (Integer/parseInt x))))))

I use that pattern quite a bit in https://github.com/sbelak/huri and with a bit of syntactic sugar it works quite well.

Comment by Imre Kószó [ 12/May/17 3:46 AM ]

Simon that will not work if you are trying to conform to specs from third parties though. One of the points of this suggestion is that third parties would be able to write their own conformers to existing specs without redefining those specs.

Comment by Tommi Reiman [ 08/Jun/17 1:40 AM ]

Thanks for the comments. I would be happy to provide a patch / sample repo with the changed needed for this, in hope that it would help to decide if this could end up in the spec or not. What do you think?

Below is a sample of initial spec-integration into ring/http libs, using spec-tools. For now, one needs to wrap specs into spec records to enable the 3-arity conforming. This is boilerplate I would like to see removed. With this change, it should work out-of-box for all (3rd party) specs.

(require '[compojure.api.sweet :refer :all])
(require '[clojure.spec.alpha :as s])
(require '[spec-tools.core :as st])

;; to enable 3-arity conforming
(defn enum [values]
  (st/spec (s/and (st/spec keyword?) values)))

(s/def ::id int?)
(s/def ::name string?)
(s/def ::description string?)
(s/def ::size (enum #{:L :M :S}))
(s/def ::country (st/spec keyword?) ;; to enable 3-arity conforming
(s/def ::city string?)
(s/def ::origin (s/keys :req-un [::country ::city]))
(s/def ::new-pizza (st/spec (s/keys :req-un [::name ::size ::origin] :opt-un [::description])))
(s/def ::pizza (st/spec (s/keys :req [::id] :req-un [::name ::size ::origin] :opt-un [::description])))

;; emits a ring-handler with input & output validation (& swagger-docs)
;; select conforming based on request content-type (e.g. json/edn) + strip-extra keys from maps
(context "/spec" []
  (resource
    {:coercion :spec
     :parameters {:body-params ::new-pizza}
     :responses {200 {:schema ::pizza}}
     :post {:handler (fn [{new-pizza :body-params}]
                       (ok (assoc new-pizza ::id 1))}}))
Comment by Tommi Reiman [ 21/Jul/17 4:13 AM ]

Intended to create internal PR in my fork of clojure.spec, but ended up doing a real DUMMY PR for the actual repo. Well, here it is anyway:

https://github.com/clojure/spec.alpha/pull/1

Happy to finalize & create a patch into Jira if this goes any further.

Comment by Tommi Reiman [ 21/Jul/17 4:14 AM ]

comments welcome. here's a sample test for it:

(deftest conforming-callback-test
  (let [string->int-conforming
        (fn [spec]
          (condp = spec
            int? (fn [_ x _]
                   (cond
                     (int? x) x
                     (string? x) (try
                                   (Long/parseLong x)
                                   (catch Exception _
                                     ::s/invalid))
                     :else ::s/invalid))
            :else nil))]

    (testing "no conforming callback"
      (is (= 1 (s/conform int? 1)))
      (is (= ::s/invalid (s/conform int? "1"))))

    (testing "with conforming callback"
      (is (= 1 (s/conform int? 1 string->int-conforming)))
      (is (= 1 (s/conform int? "1" string->int-conforming))))))
Comment by Tommi Reiman [ 22/Jul/17 2:12 AM ]

initial work as patch.

Comment by Tommi Reiman [ 04/Oct/17 1:02 AM ]

Any news on this?

Comment by Tommi Reiman [ 31/Oct/17 12:05 PM ]

Related https://dev.clojure.org/jira/browse/CLJ-2251





[CLJ-1517] Unrolled small vectors Created: 01/Sep/14  Updated: 18/May/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.7
Fix Version/s: Backlog

Type: Enhancement Priority: Critical
Reporter: Zach Tellman Assignee: Unassigned
Resolution: Unresolved Votes: 23
Labels: collections, performance

Attachments: File unrolled-collections-2.diff     File unrolled-collections.diff     Text File unrolled-vector-2.patch     Text File unrolled-vector.patch    
Patch: Code
Approval: Incomplete

 Description   

As discussed on the mailing list [1], this patch has two unrolled variants of vectors and maps, with special inner classes for each cardinality. Currently both grow to six elements before spilling over into the general versions of the data structures, which is based on rough testing but can be easily changed. At Rich's request, I haven't included any integration into the rest of the code, and there are top-level static create() methods for each.

The sole reason for this patch is performance, both in terms of creating data structures and performing operations on them. This can be seen as a more verbose version of the trick currently played with PersistentArrayMap spilling over into PersistentHashMap. Based on the benchmarks, which can be run by cloning cambrian-collections [2] and running 'lein test :benchmark', this should supplant PersistentArrayMap. Performance is at least on par with PAM, and often much faster. Especially noteworthy is the creation time, which is 5x faster for maps of all sizes (lein test :only cambrian-collections.map-test/benchmark-construction), and on par for 3-vectors, but 20x faster for 5-vectors. There are similar benefits for hash and equality calculations, as well as calls to reduce().

This is a big patch (over 5k lines), and will be kind of a pain to review. My assumption of correctness is based on the use of collection-check, and the fact that the underlying approach is very simple. I'm happy to provide a high-level description of the approach taken, though, if that will help the review process.

I'm hoping to get this into 1.7, so please let me know if there's anything I can do to help accomplish that.

[1] https://groups.google.com/forum/#!topic/clojure-dev/pDhYoELjrcs
[2] https://github.com/ztellman/cambrian-collections

Patch: unrolled-vector-2.patch

Screener Notes: The approach is clear and understandable. Given the volume of generated code, I believe that best way to improve confidence in this code is to get people using it asap, and add collection-test [3] to the Clojure test suite. I would also like to get the generator [4] included in the Clojure repo. We don't need to necessarily automate running it, but would be nice to have it nearby if we want to tweak something later.

[3] https://github.com/ztellman/collection-check/blob/master/src/collection_check.clj
[4] https://github.com/ztellman/cambrian-collections/blob/master/generate/cambrian_collections/vector.clj



 Comments   
Comment by Zach Tellman [ 01/Sep/14 10:13 PM ]

Oh, I forgot to mention that I didn't make a PersistentUnrolledSet, since the existing wrappers can use the unrolled map implementation. However, it would be moderately faster and more memory efficient to have one, so let me know if it seems worthwhile.

Comment by Nicola Mometto [ 02/Sep/14 5:23 AM ]

Zach, the patch you added isn't in the correct format, they need to be created using `git format-patch`

Comment by Nicola Mometto [ 02/Sep/14 5:31 AM ]

Also, I'm not sure if this is on-scope with the ticket but those patches break with *print-dup*, as it expects a static create(x) method for each inner class.

I'd suggest adding a create(Map x) static method for the inner PersistentUnrolledMap classes and a create(ISeq x) one for the inner PersistentUnrolledVector classes

Comment by Alex Miller [ 02/Sep/14 8:14 AM ]

Re making patches, see: http://dev.clojure.org/display/community/Developing+Patches

Comment by Jozef Wagner [ 02/Sep/14 9:16 AM ]

I wonder what is the overhead of having meta and 2 hash fields in the class. Have you considered a version where the hash is computed on the fly and where you have two sets of collections, one with meta field and one without, using former when the actual metadata is attached to the collection?

Comment by Zach Tellman [ 02/Sep/14 12:13 PM ]

I've attached a patch using the proper method. Somehow I missed the detailed explanation for how to do this, sorry. I know the guidelines say not to delete previous patches, but since the first one isn't useful I've deleted it to minimize confusion.

I did the print-dup friendly create methods, and then realized that once these are properly integrated, 'pr' will just emit these as vectors. I'm fairly sure the create methods aren't necessary, so I've commented them out, but I'm happy to add them back in if they're useful for some reason I can't see.

I haven't given a lot of thought to memory efficiency, but I think caching the hashes are worthwhile. I can see an argument for creating a "with-meta" version of each collection, but since that would double the size of an already enormous patch, I think that should probably wait.

Comment by Zach Tellman [ 03/Sep/14 4:31 PM ]

I found a bug! Like PersistentArrayMap, I have a special code path for comparing keywords, but my generators for collection-check were previously using only integer keys. There was an off-by-one error in the transient map implementation [1], which was not present for non-keyword lookups.

I've taken a close look for other gaps in my test coverage, and can't find any. I don't think this substantively changes the risk of this patch (an updated version of which has been uploaded as 'unrolled-collections-2.diff'), but obviously where there's one bug, there may be others.

[1] https://github.com/ztellman/cambrian-collections/commit/eb7dfe6d12e6774512dbab22a148202052442c6d#diff-4bf78dbf5b453f84ed59795a3bffe5fcR559

Comment by Zach Tellman [ 03/Oct/14 2:34 PM ]

As an additional data point, I swapped out the data structures in the Cheshire JSON library. On the "no keyword-fn decode" benchmark, the current implementation takes 6us, with the unrolled data structures takes 4us, and with no data structures (just lexing the JSON via Jackson) takes 2us. Other benchmarks had similar results. So at least in this scenario, it halves the overhead.

Benchmarks can be run by cloning https://github.com/dakrone/cheshire, unrolled collections can be tested by using the 'unrolled-collections' branch. The pure lexing benchmark can be reproduced by messing around with the cheshire.parse namespace a bit.

Comment by Zach Tellman [ 06/Oct/14 1:31 PM ]

Is there no way to get this into 1.7? It's an awfully big win to push off for another year.

Comment by Alex Miller [ 07/Oct/14 2:08 PM ]

Hey Zach, it's definitely considered important but we have decided to drop almost everything not fully done for 1.7. Timeframe for following release is unknown, but certainly expected to be significantly less than a year.

Comment by John Szakmeister [ 30/Oct/14 2:53 PM ]

You are all free to determine the time table, but I thought I'd point out that Zach is not entirely off-base. Clojure 1.4.0 was released April 5th, 2012. Clojure 1.5.0 was released March 1st, 2013 with 1.6.0 showing up March 25th, 2014. So it appears that the current cadence is around a year.

Comment by Alex Miller [ 30/Oct/14 3:40 PM ]

John, there is no point to comments like this. Let's please keep issue comments focused on the issue.

Comment by Zach Tellman [ 13/Nov/14 12:23 PM ]

I did a small write-up on this patch which should help in the eventual code review: http://blog.factual.com/using-clojure-to-generate-java-to-reimplement-clojure

Comment by Zach Tellman [ 07/Dec/14 10:34 PM ]

Per my conversation with Alex at the Conj, here's a patch that only contains the unrolled vectors, and uses the more efficient constructor for PersistentVector when spilling over.

Comment by Alex Miller [ 08/Dec/14 1:10 PM ]

Zach, I created a new placeholder for the map work at http://dev.clojure.org/jira/browse/CLJ-1610.

Comment by Jean Niklas L'orange [ 09/Dec/14 1:52 PM ]

It should probably be noted that core.rrb-vector will break for small vectors by this patch, as it peeks into the underlying structure. This will also break other libraries which peeks into the vector implementation internals, although I'm not aware of any other – certainly not any other contrib library.

Also, two comments on unrolled-vector.patch:

private transient boolean edit = true;
in the Transient class should probably be
private volatile boolean edit = true;
as transient means something entirely different in Java.

conj in the Transient implementation could invalidate itself without any problems (edit = false;) if it is converted into a TransientVector (i.e. spills over) – unless it has a notable overhead. The invalidation can prevent some subtle bugs related to erroneous transient usage.

Comment by Alex Miller [ 09/Dec/14 1:58 PM ]

Jean - understanding the scope of the impact will certainly be part of the integration process for this patch. I appreciate the heads-up. While we try to minimize breakage for things like this, it may be unavoidable for libraries that rely on implementation internals.

Comment by Michał Marczyk [ 09/Dec/14 2:03 PM ]

I'll add support for unrolled vectors to core.rrb-vector the moment they land on master. (Probably with some conditional compilation so as not to break compatibility with earlier versions of Clojure – we'll see when the time comes.)

Comment by Michał Marczyk [ 09/Dec/14 2:06 PM ]

I should say that it'd be possible to add generic support for any "vector lookalikes" by pouring them into regular vectors in linear time. At first glance it seems to me that that'd be out of line with the basic promise of the library, but I'll give it some more thought before the changes actually land.

Comment by Zach Tellman [ 09/Dec/14 5:43 PM ]

Somewhat predictably, the day after I cut the previous patch, someone found an issue [1]. In short, my use of the ArrayChunk wrapper applied the offset twice.

This was not caught by collection-check, which has been updated to catch this particular failure. It was, however, uncovered by Michael Blume's attempts to merge the change into Clojure, which tripped a bunch of alarms in Clojure's test suite. My own attempt to do the same to "prove" that it worked was before I added in the chunked seq functionality, hence this issue persisting until now.

As always, there may be more issues lurking. I hope we can get as many eyeballs on the code between now and 1.8 as possible.

[1] https://github.com/ztellman/cambrian-collections/commit/2e70bbd14640b312db77590d8224e6ed0f535b43
[2] https://github.com/MichaelBlume/clojure/tree/test-vector

Comment by Zach Tellman [ 10/Jul/15 1:54 PM ]

As a companion to the performance analysis in the unrolled map issue, I've run the benchmarks and posted the results at https://gist.github.com/ztellman/10e8959501fb666dc35e. Some notable results:

Comment by Alex Miller [ 13/Jul/15 9:02 AM ]

Stu: I do not think this patch should be marked "screened" until the actual integration and build work (if the generator is integrated) has been completed.

Comment by Alex Miller [ 14/Jul/15 4:33 PM ]

FYI, we have "reset" all big features for 1.8 for the moment (except the socket repl work). We may still include it - that determination will be made later.

Comment by Zach Tellman [ 14/Jul/15 4:43 PM ]

Okay, any idea when the determination will be made? I was excited that we seemed to be finally moving forward on this.

Comment by Alex Miller [ 14/Jul/15 4:51 PM ]

No, but it is now on my work list.

Comment by Rich Hickey [ 15/Jul/15 8:17 AM ]

I wonder if all of the overriding of APersistentVector yields important benefits - e.g. iterator, hashcode etc.

Comment by Zach Tellman [ 15/Jul/15 11:51 AM ]

In the case of hashcode, definitely: https://gist.github.com/ztellman/10e8959501fb666dc35e#file-gistfile1-txt-L1013-L1076. This was actually one of the original things I wanted to speed up.

In the case of the iterator, probably not. I'd be fine removing that.

Comment by Zach Tellman [ 16/Jul/15 5:17 PM ]

So am I to infer from https://github.com/clojure/clojure/commit/36d665793b43f62cfd22354aced4c6892088abd6 that this issue is defunct? If so, I think there's a lot of improvements being left on the table for no particular reason.

Comment by Rich Hickey [ 16/Jul/15 6:34 PM ]

Yes, that commit covers this functionality. It takes a different approach from the patch in building up from a small core, and maximizing improvements to the bases rather than having a lot of redundant definitions per class. That also allowed for immediate integration without as much concern for correctness, as there is little new code. It also emphasizes the use case for tuples, e.g. small vectors used as values that won't be changed, thus de-emphasizing the 'mutable' functions. I disagree that many necessary improvements are being left out. The patch 'optimized' many things that don't matter. Further, there are not big improvements to the pervasive inlining. In addition, the commit includes the integration work at a fraction of the size of the patch. In all, it would have taken much more back and forth to get the patch to conform with this approach than to just get it all done, but I appreciate the inspiration and instigation - thanks!

Comment by Rich Hickey [ 16/Jul/15 6:46 PM ]

That said, this commit need not be the last word - it can serve as a baseline for further optimization. But I'd rather that be driven by need. Clojure could become 10x as large optimizing things that don't matter.

Comment by Zach Tellman [ 19/Jul/15 1:36 PM ]

What is our reference for "relevant" performance? I (or anyone else) can provide microbenchmarks for calculating hashes or whatever else, but that doesn't prove that it's an important improvement. I previously provided benchmarks for JSON decoding in Cheshire, but that's just one of many possible real-world benchmarks. It might be useful to have an agreed-upon list of benchmarks that we can use when debating what is and isn't useful.

Comment by Mike Anderson [ 19/Jul/15 11:14 PM ]

I was interested in this implementation so created a branch that integrates Zach's unrolled vectors on top of clojure 1.8.0-alpha2. I also simplified some of the code (I don't think the metadata handling or unrolled seqs are worthwhile, for example)

Github branch: https://github.com/mikera/clojure/tree/clj-1517

Then I ran a set of micro-benchmarks created by Peter Taoussanis

Results: https://gist.github.com/mikera/72a739c84dd52fa3b6d6

My findings from this testing:

  • Performance is comparable (within +/- 20%) on the majority of tests
  • Zach's approach is noticeably faster (by 70-150%) for 4 operations (reduce, mapv, into, equality)

My view is that these additional optimisations are worthwhile. In particular, I think that reduce and into are very important operations. I also care about mapv quite a lot for core.matrix (It's fundamental to many numerical operations on arrays implemented using Clojure vectors).

Happy to create a patch along these lines if it would be acceptable.

Comment by Zach Tellman [ 19/Jul/15 11:45 PM ]

The `reduce` improvements are likely due to the unrolled reduce and kvreduce impls, but the others are probably because of the unrolled transient implementation. The extra code required to add these would be pretty modest.

Comment by Mike Anderson [ 20/Jul/15 9:20 PM ]

I actually condensed the code down to a single implementation for `Transient` and `TupleSeq`. I don't think these really need to be fully unrolled for each Tuple type. That helps by making the code even smaller (and probably also helps performance, given JVM inline caching etc.)

Comment by Peter Taoussanis [ 21/Jul/15 11:46 AM ]

Hey folks,

Silly question: is there actually a particular set of reference benchmarks that everyone's currently using to test the work on tuples? It took me a while to notice how bad the variance was with my own set of micro benchmarks.

Bumping all the run counts up till the noise starts ~dying down, I'm actually seeing numbers now that don't seem to agree with others here .

Google Docs link: https://docs.google.com/spreadsheets/d/1QHY3lehVF-aKrlOwDQfyDO5SLkGeb_uaj85NZ7tnuL0/edit?usp=sharing
gist with the benchmarks: https://gist.github.com/ptaoussanis/0a294809bc9075b6b02d

Thanks, cheers!

Comment by Zach Tellman [ 21/Jul/15 6:52 PM ]

Hey Peter, I can't reproduce your results, and some of them are so far off what I'd expect that I have to think there was some data gathering error. For instance, the assoc operation being slower is kind of inexplicable, considering the unrolled version doesn't do any copying, etc. Also, all of your numbers are significantly slower than the ones on my 4 year old laptop, which is also a bit strange.

Just to make sure that we're comparing apples to apples, I've adapted your benchmarks into something that pretty-prints the mean runtime and variance for 1.7, 1.8-alpha2, and Mike's 1517 fork. It can be found at https://github.com/ztellman/tuple-benchmark, and the results of a run at https://gist.github.com/ztellman/3701d965228fb9eda084.

Comment by Mike Anderson [ 22/Jul/15 2:24 AM ]

Hey Zach just looked at your benchmarks and they are definitely more consistent with what I am seeing. The overall nanosecond timings look about right from my experience with similar code (e.g. working with small vectors in vectorz-clj).

Comment by Peter Taoussanis [ 22/Jul/15 2:41 AM ]

Hi Zach, thanks for that!

Have updated the results -
Gist: https://gist.github.com/ptaoussanis/0a294809bc9075b6b02d
Google docs: https://goo.gl/khgT83

Note that I've added an extra sheet/tab to the Google doc for your own numbers at https://gist.github.com/ztellman/3701d965228fb9eda084.

Am still struggling to produce results that show any consistent+significant post-JIT benefit to either of the tuple implementations against the micro benchmarks and one larger small-vec-heavy system I had handy.

It's looking to me like it's maybe possible that the JIT's actually optimising away most of the non-tuple inefficiencies in practice?

Of course it's very possible that my results are off, or my expectations wrong. The numbers have been difficult to pin down.

It definitely helped to have a standardised reference micro benchmark to work against (https://github.com/ztellman/tuple-benchmark). Could I perhaps suggest a similar reference macro benchmark (maybe something from core.matrix, Mike?)

Might also be a good idea to define a worthwhile target performance delta for ops like these that run in the nanosecond range (or for the larger reference macro benchmark)?

Just some thoughts from someone passing through in case they're at all useful; know many of you have been deeply involved in this for some time so please feel free to ignore any input that's not helpful

Appreciate all the efforts, cheers!

Comment by Rich Hickey [ 22/Jul/15 9:24 AM ]

I think everyone should back off on their enthusiasm for this approach. After much analysis, I am seeing definite negative impacts to tuples, especially the multiple class approach proposed by Zach. What happens in real code is that the many tuple classes cause call sites that see different sized vectors to become megamorphic, and nothing gets adequately optimized. In particular, call sites that will see tuple-sized and large vectors (i.e. a lot of library code) will optimize differently depending upon which they see often first. So, if you run your first tight loop on vector code that sees tuples, that code could later do much worse (50-100%) on large vectors than before the tuples patch was in place. Being much slower on large collections is a poor tradeoff for being slightly faster on small ones.

Certainly different tuple classes for arity 0-6 is a dead idea. You get as good or better optimization (at some cost in size) from a single class e.g. one with four fields, covering sizes 0-4. I have a working version of this in a local branch. It is better in that sites that include pvectors are only bi-morphic, but I am still somewhat skittish given what I've seen.

The other takeaway is that the micro benchmarks are nearly worthless for detecting these issues.

Comment by Zach Tellman [ 22/Jul/15 11:07 AM ]

I'm pretty sure that all of my real-world applications of the tuples (via clj-tuple) have been fixed cardinality, and wouldn't have surfaced any such issue. Thanks for putting the idea through its paces.

Comment by Mike Anderson [ 22/Jul/15 10:37 PM ]

Rich these are good insights - do you have a benchmark that you are using as representative of real world code?

I agree that it is great if we can avoid call sites becoming megamorphic, though I also believe the ship has sailed on that one already when you consider the multiple types of IPersistentVector that already exist (MapEntry, PersistentVector, SubVector plus any library-defined IPersistentVector instances such as clojure.core.rrb-vector). As a consequence, the JVM is usually not going to be able to prove that a specific IPersistentVector interface invocation is monomorphic, which is when the really big optimisations happen.

In most of the real world code that I've been working with, the same size/type of vector gets used repeatedly (Examples: iterating over map entries, working with a sequence of size-N vectors), so in such cases we should be able to rely on the polymorphic inline cache doing the right thing.

The idea of a single Tuple class for sizes 0-4 is interesting, though I can't help thinking that a lot of the performance gain from this may stem from the fact that a lot of code does stuff like (reduce conj [] .....) or the transient equivalent which is a particularly bad use case for Tuples, at least from the call site caching perspective. There may be a better way to optimise such cases rather than simply trying to make Tuples faster.... e.g. calling asTransient() on a Tuple0 could perhaps switch straight into the PersistentVector implementation.

Comment by Colin Fleming [ 18/May/16 8:32 PM ]

Here's a relevant issue from Google's Guava project, where they also found serious performance degradation with fixed-size collections: https://github.com/google/guava/issues/1268. It has a lot of interesting detail about how the performance breaks down.





[CLJ-865] Macroexpansion discards &form metadata Created: 26/Oct/11  Updated: 05/Dec/14

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: Alan Malloy Assignee: Unassigned
Resolution: Unresolved Votes: 23
Labels: Compiler

Attachments: Text File 0001-Add-test-for-macroexpansion-metadata-preservation.patch     Text File 0002-Preserve-form-metadata-on-macroexpanded-forms.patch     Text File 0003-Make-defmacro-preserve-form-metadata.patch     Text File 0004-Another-stab-at-implementing-this.patch     File 2013-10-11_CLJ-865_Fix-With-Tests.diff     Text File clj-865.patch     Text File clj865.patch     Text File clj-865-updated-v2-patch.txt     Text File updated.patch    
Patch: Code and Test
Approval: Vetted

 Description   

This patch changes the behavior of metadata when used in conjunction with macros. The metadata &form is now merged with the metadata of the macro call sexpr. This allows users to either type-hint the inner or the outer form in a macro call and have somewhat better results. In the past, the metadata from the macroexpand was used as-is. This disallowed code like the following, to work without reflection:

(.trim ^String (when true "hello "))

Patch: 2013-10-11_CLJ-865_Fix-With-Tests.diff
Screened by: Timothy Baldridge

--------- Implementation Details ----------

As discussed in http://groups.google.com/group/clojure/browse_thread/thread/2690cb6ca0e8beb8 there is a "surprise factor" when type-hinting an expression that represents a macro, such as with (.length ^String (doto (identity "x") prn)). Here the doto macro discards the metadata on &form, causing a reflective lookup. This has the effect that while expressions representing function calls can be type-hinted, expressions representing macros in general cannot. The doto macro could be rewritten to respect its &form metadata, but doing this for every macro in existence would be tedious and error-prone. Instead, I propose a change to the compiler, to cause macroexpansion to hang onto the metadata automatically.

The first patch attached adds a test for the behavior I propose: this test fails. After applying the second patch, the test passes.

There are a couple points that merit further consideration before accepting my patch:

  • I'm not sure I actually got the Java code formatted correctly. My editor is not well-configured to get the clojure/core style right automatically.
  • My solution is to take the &form metadata, drop :line/:file keys, and then merge with the returned metadata, with &form taking precedence. I'm not sure whether this is the right approach in all cases, even though it works for :tag metadata.
  • I achieved this with a change to the compiler, which makes it fairly heavy-weight. It should be possible to instead adjust defmacro if changes to the compiler are not desirable. However, I believe this would involve substantially more work and be harder to test (for example, multiple arities complicate things). It seems nicer to treat the macroexpansion as a black box and then make metadata tweaks to the result, rather than modifying their actual defmacro code.
  • If a macro expands to something that is not an IObj, such as an Integer, then my patch silently discards the caller's metadata. Would it be better to throw an exception?


 Comments   
Comment by Alan Malloy [ 28/Oct/11 1:12 AM ]

So I went ahead and did the work of making this change in clojure.core/defmacro instead of clojure.lang.Compiler/macroexpand1. It was even worse than I expected: I didn't realize we don't yet have syntax-quote or apply at this stage in bootstrapping, so writing a non-trivial macroexpansion requires a huge amount of (list `foo (list `bar 'local-name)) and so forth.

I'm sure the version I wrote is not optimal, but it seemed simpler to piggyback on defn, and then use alter-var-root to shim the metadata management in, than it would have been to expand to the correct thing in the first place.

Anyway, attached patch #3 could be applied instead of #2 to resolve the issue in clojure.core instead of clojure.lang. The tests added in patch #1 pass either way.

Comment by Alan Malloy [ 13/Nov/11 8:29 PM ]

I realized I can do this with a named private function instead of an anonymous function, reducing the amount of mess defmacro itself has to generate. Patch 4 is, I think, strictly better than Patch 3, if a Clojure implementation is preferred to one in Java.

Comment by Chouser [ 20/Nov/11 10:43 PM ]

I prefer patch 0002 in Java over either 0003 or 0004. Patch 0002 keeps the knowledge of how to invoke macro fns (specifically the extra &form and &env args) in one place, macroexpand1 rather than duplicating that knowledge in core.clj as well. Note patch 0001 is just tests.

The proposed default macroexpansion behavior is more useful than what we currently have, but there are two details I'd like to think about a bit more:

1) In exchange for a more useful default, macro writers lose the ability to consume their &form metadata and have control over the resulting form metadata without the &form metadata overridding it. That is, macros are no longer in complete control of their output form.

2) Rule (1) above has hardcoded exceptions for :line and :file, where &form metadata is unable to override the results returned by the macro.

Comment by Alan Malloy [ 01/Jun/12 2:04 PM ]

This patch incorporates all previous patches to this issue.

On the clj-dev mailing list, Andy Fingerhut suggested a new metadata key for allowing the macro author to specify "I've looked at their &form metadata, and this form is exactly what I want to expand to, please don't change the metadata any further." I've implemented this, and I think it addresses Chouser's concern about needing a way to "break out" of the improved-default behavior.

One open question is, is :explicit-meta the right key to use? I spent some time tracking down a bug caused by my forgetting the keyword and using :explicit-metadata in my test; perhaps something more difficult to get confused by is available.

Comment by Andy Fingerhut [ 14/Aug/13 8:05 PM ]

clj-865-updated-v2-patch.txt dated Aug 14 2013 is identical to Alan Malloy's updated.patch dated Jun 1 2012. I simply updated the patch to apply cleanly to latest master after some context lines in the test file macros.clj had gone bad due to recent commits.

Comment by Timothy Baldridge [ 11/Oct/13 9:23 AM ]

Added updated patch that works against master, and also removes COLUMN_KEY from the macro's metadata

Comment by Timothy Baldridge [ 11/Oct/13 12:50 PM ]

Added patch that contains all fixes plus a few more tests.

Comment by Rich Hickey [ 22/Nov/13 11:19 AM ]

Since this could break things, we could just take metadata on the macro name to ask for this:

(defmacro ^:keep-meta simple-macro [f arg]
  `(~f ~arg))

or something

Comment by Alan Malloy [ 03/Dec/13 1:24 AM ]

Sure, I'll put together that patch. I'm worried, though, that if it's not the default, it will just never get used, and we'll be in effectively the same situation we are now, where no macros do this right. I don't foresee anyone going through their libraries to add ^:keep-meta on every macro.

Comment by Alan Malloy [ 03/Dec/13 2:20 AM ]

I updated the patch to behave as Rich requested, but it caused a test regression that I can't figure out, in the handling of either refer or private vars. Hopefully someone else can run the tests and figure out what is missing here; my change is supposed to be opt-in, and I can't see where I've gone wrong.

Comment by Andy Fingerhut [ 07/Dec/13 10:31 AM ]

Alan, your patch clj865.patch dated Dec 3, 2013 has some HTML cruft at the beginning and end, but even after removing that it does not apply cleanly to the latest Clojure master as of today. I understand that you say it needs more work, but it would be easier for others who wish to try it out if it applied cleanly.

Comment by Alan Malloy [ 10/Dec/13 1:06 PM ]

Sorry Andy, and thanks for noticing. I haven't been on a very developer-friendly computer recently, but I'll try to fix the patch tonight.

Comment by Alan Malloy [ 11/Dec/13 10:26 AM ]

Here's a fix to the patch. I verified that this applies cleanly to current master.

Comment by Alan Malloy [ 11/Dec/13 10:27 AM ]

To clarify, it's the file named clj-865.patch. I didn't realize JIRA wouldn't make it clear which file I uploaded along with the comment.

Comment by Andy Fingerhut [ 05/Dec/14 1:54 PM ]

As of Eastwood version 0.2.0, it includes a new warning :unused-meta-on-macro that will warn whenever metadata is applied to a macro invocation, with the known exception of clojure.core/fn, which explicitly uses metadata applied to it. https://github.com/jonase/eastwood#unused-meta-on-macro





[CLJ-706] make use of deprecated namespaces/vars easier to spot Created: 05/Jan/11  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Critical
Reporter: Stuart Halloway Assignee: Cezary Kosko
Resolution: Unresolved Votes: 22
Labels: errormsgs

Attachments: File 706-deprecated-ns-var-warnings-tested-2.diff     File 706-deprecated-ns-var-warnings-tested-3.diff     File 706-deprecated-ns-var-warnings-tested.diff     File 706-deprecated-var-warning.diff     Text File 706-deprecated-var-warning-patch-v2.txt     File 706-fix-deprecation-warnings-agents.diff     File 706-fix-deprecation-warnings-on-replicate.diff     File 706-fix-deprecation-warning-test-junit.diff     File 706-warning-on-deprecated-ns.diff    
Approval: Prescreened

 Description   

From the mailing list http://groups.google.com/group/clojure/msg/c41d909bd58e4534. It is easy to use deprecated namespaces or vars without knowing you are doing so. The documentation warnings are small, and there is no compiler warning.

Proposed:

  • Add new *warn-on-deprecated* dynamic var, defaulted to false
  • Warn to stderr when {:deprecated true} namespace is loaded.
  • Warn to stderr when {:deprecated true} var is analyzed.
  • Warn to stderr when {:deprecated true} macro is expanded.
  • New system property clojure.compiler.warn-on-deprecated
  • Compile Clojure itself with clojure.compiler.warn-on-deprecated
  • Fix deprecation warnings inside Clojure (replicate, clear-agent-errors)
  • Mark clojure.parallel as deprecated with :deprecation tag

Examples:

(set! *warn-on-deprecated* true)

;; use of a deprecated var (on compile)
(defn ^:deprecated f [x] x)
(f 5)
;;=> Deprecation warning, NO_SOURCE_PATH:7:1 : var #'user/f is deprecated

;; use of a deprecated macro (on macro expansion)
(defmacro ^:deprecated m [x] x)
(m 5)
;;=> Deprecation warning, NO_SOURCE_PATH:7:1 : macro #'user/m is deprecated

;; use of a deprecated namespace (on load)
(ns foo {:deprecated "1.1"})
(ns bar (:require foo))
;;=> Deprecation warning: loading deprecated namespace `foo` from namespace `bar`

Patch: 706-deprecated-ns-var-warnings-tested-3.diff

Questions: Should default for deprecation warnings be true instead? People upgrading are likely to see new warnings which might be surprising.

  • Should default be to warn or not warn on deprecated?


 Comments   
Comment by Rich Hickey [ 07/Jan/11 9:38 AM ]

I don't mind warning to stderr

Comment by Luke VanderHart [ 26/Oct/12 1:37 PM ]

706-deprecated-var-warning.diff adds warnings when using deprecated vars. The other three patches clean up deprecation warnings.

Comment by Andy Fingerhut [ 26/Oct/12 2:23 PM ]

Great stuff. I looked through the first patch, and didn't see anything in there that lets someone disable deprecation warnings from the command line, the way that warn-on-reflection can today be set to true with a command line option.

Is that something important to have for deprecation warnings?

Comment by Andy Fingerhut [ 28/Oct/12 4:57 PM ]

I was hoping it would be quick and easy to add source file, line, and column info to the deprecation warning messages. It isn't as easy as adding them to the format() call, because the method analyzeSymbol doesn't receive these values as args. Is this deprecation check being done in a place where it is not easy to relate it to the source file, line, and column? Could it be done in a place where that info is easily available?

Comment by Ghadi Shayban [ 29/Oct/12 1:02 AM ]

Another patch - this time to warn on loading deprecated namespaces, instead of vars. This patch requires the first one.

Re: line/column, I'll figure out how to thread the compile context through if it's desired.

Re: Compile flag. I have a patch for this also, but I'm still verifying how to invoke. How is warn-on-reflection set by command line?

Comment by Andy Fingerhut [ 29/Oct/12 1:43 AM ]

Re: Compile flag. Don't hold off on implementing a flag if you want to, but it might be worth hearing from others whether such a command line option is even desired. I was asking in hopes of eliciting such a response.

For the way that it is handled in the Clojure compiler, search for REFLECTION_WARNING_PROP and related code in Compile.java. If you invoke the Clojure compiler directly via a Java command line, use -Dclojure.compile.warn-on-reflection=true (default is false). See the recent email thread sent to Clojure Dev Google group if you want to know how to do it via ant or Maven. Link: https://mail.google.com/mail/?shva=1#label/clojure-dev/13aa0e34530196c3

There is also a separate command-line flag called compiler-options (see Compile.java) that is implemented as a map inside the compiler. It was added more recently than warn-on-reflection, and might be the preferred method to add more such options, to avoid having to continue to add more arguments to the pushThreadBindings calls done in several places.

Comment by Ghadi Shayban [ 29/Oct/12 10:36 AM ]

Thanks, Andy.

Alternately for the last ns patch, it is equivalent to call (print-method msg err), rather than binding out to err, may be more readable. I'll be glad to send that in if it's preferable.

Comment by Andy Fingerhut [ 13/Feb/13 12:38 AM ]

706-deprecated-var-warning-patch-v2.txt dated Feb 12 2013 is identical to 706-deprecated-var-warning.diff dated Oct 26 2012, except it applies cleanly to latest master.

Comment by Andy Fingerhut [ 23/Feb/15 8:21 PM ]

For the information of anyone examining this ticket wishing for this feature, the Eastwood lint tool reports calls to deprecated Clojure functions, and also to deprecated Java methods. https://github.com/jonase/eastwood

Comment by Alex Miller [ 25/Jan/16 12:32 PM ]

I'm interested in considering this for Clojure 1.9 but I need some help getting it ready. Some comments I have on the current state: - Ticket needs to have more details about the current approach

  • I prefer *warn-on-deprecated* over *warn-on-deprecation* because it echoes the keyword you use to mark deprecated vars
  • The warning message does not tell you a location, which is grr - should be similar to the reflection messages
  • Needs tests - see test/clojure/test_clojure/compilation.clj and test/clojure/test_helper.clj (should-not-reflect) for examples
  • clojure itself has some instances of deprecated usage - it would be nice to clean those up in the patch too. That may need to be in a separate patch, depends if they are easy to fix or not. If there are cases in test/ that are actually good to leave, can set *warn-on-deprecated* to false in that namespace.
  • Current default is true - should probably be false instead to match the reflection warning default.
Comment by Vijay Kiran [ 26/Jan/16 3:10 AM ]

Alex Miller I can give this a shot.

Comment by Alex Miller [ 26/Jan/16 8:51 AM ]

Hey Vijay, Andrew Rosa assigned it to himself so please coordinate with him as he was starting to work on it.

Comment by Bozhidar Batsov [ 26/Jan/16 10:52 AM ]

Just one small remark - isn't it more common to have deprecation warnings enabled by default? One could argue they are way more important than reflection warnings, as your code might get broken in the future because you didn't notice you were using deprecated stuff.

Comment by Alex Miller [ 26/Jan/16 2:01 PM ]

Bozhidar Batsov I'm on the fence. My main hesitation in making it the default is that people will suddenly have a bunch of new warnings (which could be either good or bad I suppose). Depends how strongly we want people to care about deprecations I guess.

Comment by Phill Wolf [ 26/Jan/16 9:33 PM ]

A deprecation warning that is off by default does not address the first and primary problem given in this ticket: "It is easy to use deprecated namespaces without knowing you are doing so."

It's unlike the reflection warning. You may focus on speed at any time, at your leisure. But the eventual removal of at-risk features will be a sudden, unpleasant surprise; a warning would be helpful.

But - Suppose I wrote 300 lines of Clojure and use a million lines that come from jars. Will any deprecation problems in my own code be buried in a tsunami of warnings about those jars? Worse, the tsunami will likely linger for weeks or months, until the libraries' respective authors catch up. Inasmuch as the jars are covered (much more expediently) by 'lein ancient' and similar, I would prefer to be able to limit deprecation warnings to just my stuff, perhaps by namespace prefix if from-a-jar-or-not is inconvenient from the compiler's point of view.

Comment by Alex Miller [ 26/Jan/16 10:35 PM ]

There is a middle ground here to turn it off by default in the compiler, but to turn it on by default in the tools (like lein). But there's a reasonable chance that whatever I prefer, Rich will have a preference that overrules it when it gets to him.

I think creating more complexity around namespace prefixes is unlikely to help this ticket move forward.

Comment by Cezary Kosko [ 07/Mar/16 9:18 PM ]

Uploaded a patch that coalesces var/ns-related patches by Luke & adds tests.
The patch does not, however, warn the user about deprecated macros, I assume I should adjust it, then?

Also, I'm not able adjust the description, so how do I take care of Alex's list's first bullet?

Comment by Andy Fingerhut [ 08/Mar/16 1:05 AM ]

Cezary, I have bumped up your permissions on JIRA so you should be able to edit tickets now. Please reload the page and try again.

Comment by Alex Miller [ 10/Mar/16 10:54 AM ]
  • The if in the first change in core.clj should be a when instead.
  • Can namespace deprecation warning include more about where this is occurring?
  • I'm having a hard time reproducing the deprecated ns warning in a manual test (see below). There seems to be something weird about the binding+printf as the conditions appear to be satisfied. I'm thinking it has something to do with flushing *err*? Seems like (println "Warning: loading deprecated ns" lib) would be better there.
(set! *warn-on-deprecated* true)
(ns foo {:deprecated true})
(ns bar (:require foo))
  • src/jvm/clojure/lang/Compile.java needs added support for clojure.compile.warn-on-deprecated RT flag
  • I think we should turn on warn-on-deprecated in the Clojure build itself (in build.xml)
  • If you do that, the following deprecation warnings exist in the Clojure build itself and we should fix those:

[java] Deprecation warning, clojure/core_proxy.clj:112:75 : var #'clojure.core/replicate is tagged as deprecated
[java] Deprecation warning, clojure/genclass.clj:149:41 : var #'clojure.core/replicate is tagged as deprecated
[java] Deprecation warning, clojure/genclass.clj:235:65 : var #'clojure.core/replicate is tagged as deprecated
[java] Deprecation warning, clojure/test/junit.clj:118:22 : var #'clojure.test/file-position is tagged as deprecated

  • Mark clojure.parallel as deprecated in the ns meta
Comment by Cezary Kosko [ 11/Mar/16 5:40 AM ]

Uploaded a new diff addressing the comments & added warning on macroexpansion.

As far as the namespace deprecation warning goes, though, the code's only printing the current namespace, did not know whether there was a decent way to get a file/line combo.

Comment by Alex Miller [ 11/Mar/16 8:53 AM ]

One more (hopefully final) round and then I think we're good:

  • The docstring for warn-on-deprecated should be updated now that we've expanded scope to cover ns too.
  • In the deprecated ns warning message, can we make it: "Deprecation warning: loading deprecated namespace `foo` from namespace `bar`."
  • In the macro and var warnings can we change "is tagged as deprecated" to just "is deprecated"?
  • Clean up the hanging parens in test/clojure/test_clojure/compilation/deprecated.clj

Thanks for the work on this!!

Comment by Alex Miller [ 11/Mar/16 1:49 PM ]

Marking pre-screened for Rich to look at.





[CLJ-304] clojure.repl/source does not work with deftype Created: 20/Apr/10  Updated: 15/May/17

Status: In Progress
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Assembla Importer Assignee: Unassigned
Resolution: Unresolved Votes: 22
Labels: repl

Approval: Triaged

 Description   

clojure.repl/source does not work on a deftype

user> (deftype Foo [a b])
user.Foo
user> (source Foo)
Source not found

Cause: deftype creates a class but not a var so no file/line info is attached anywhere.

Approach:

Patch:

Screened by:



 Comments   
Comment by Assembla Importer [ 24/Aug/10 4:38 PM ]

Converted from http://www.assembla.com/spaces/clojure/tickets/304

Comment by Assembla Importer [ 24/Aug/10 4:38 PM ]

chouser@n01se.net said: That's a great question. get-source just needs a file name and line number.

If IMeta were a protocol, it could be extended to Class. That implementation could look for a "well-known" static field, perhaps? __clojure_meta or something? Then deftype would just have to populate that field, and get-source would be all set.

Does that plan have any merit? Is there a better place to store a file name and line number?

Comment by Assembla Importer [ 24/Aug/10 4:38 PM ]

stu said: Seems like a reasonable idea, but this is going to get back-burnered for now, unless there is a dire use case we have missed.

Comment by Gary Trakhman [ 19/Feb/14 10:31 AM ]

I could use this for cider's file/line jump-around mechanism as well.

With records, I can work around it by deriving and finding the corresponding constructor var, but it's a bit nasty.

Comment by Bozhidar Batsov [ 03/Mar/14 6:37 AM ]

I'd also love to see this fixed.

Comment by Andy Fingerhut [ 03/Mar/14 8:33 AM ]

Bozhidar, voting on a ticket (clicking the Vote link in the right of the page when viewing the ticket) can help push it upwards on listings of tickets by # of votes.

Comment by Bozhidar Batsov [ 19/Sep/14 1:17 PM ]

Andy, thanks for the pointer. They should have made this button much bigger, I hadn't noticed it all until now.

Comment by Alex Miller [ 26/Jan/16 4:12 PM ]

If someone did some work on this (like a patch), I would push it harder.

Comment by Baptiste Dupuch [ 19/Jan/17 2:45 PM ]

it's "working" for me using this =>

(source source-training.source/->Foo)




[CLJ-1522] Enhance multimethods metadata Created: 08/Sep/14  Updated: 26/Jan/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Enhancement Priority: Critical
Reporter: Bozhidar Batsov Assignee: Unassigned
Resolution: Unresolved Votes: 19
Labels: metadata

Approval: Triaged

 Description   

I think that multimethod metadata can be extended a bit with some property indicating the var in question is referring to a multimethod (we have something similar for macros) and some default arglists property.

I'm raising this issue because as a tool writer (CIDER) I'm having hard time determining if something is a multimethod (I have to resort to code like (instance? clojure.lang.MultiFn obj) which is acceptable, but not ideal I think (compared to macros and special forms)). There's also the problem that I cannot provide the users with eldoc (function signature) as it's not available in the metadata (this issue was raised on the mailing list as well https://groups.google.com/forum/#!topic/clojure/crje_RLTWdk).

I feel that we really have a problem with the missing arglist and we should solve it somehow. I'm not sure I'm suggesting the best solution and I'll certainly take any solution.



 Comments   
Comment by Bozhidar Batsov [ 09/Sep/14 4:24 AM ]

Btw, I failed to mention this as I thought it was obvious, but I think we should use the dispatch function's arglist in the multimethod metadata.





[CLJ-2123] Lighter-weight aliasing for keywords Created: 10/Mar/17  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: Release 1.10

Type: Feature Priority: Major
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 18
Labels: keywords, namespace

Approval: Vetted

 Description   

It is useful to make qualified keywords, and particularly so with spec. Using namespace aliases helps a lot in working with a lot of qualified keywords. However, currently creating an aliased namespace requires that the namespace actually exists.

This ticket is a placeholder to do something more with lighter-weight aliasing for keywords. Details TBD.



 Comments   
Comment by Herwig Hochleitner [ 26/Sep/17 8:01 PM ]

Hoping to get the conversation started on this in time for a 1.9-beta:

The rationale in my predecessor ticket, CLJ-2030, was to create a construct to allow for auto-aliasing in .cljc files, which I would like to submit as a requirement. The obvious place for cljs to declare an auto-alias is the ns clause.
So if we don't want to grow alias for that use case, I would propose to grow the ns clause with a declaration for keyword - aliases. Let's give it a working title of (:kwns-alias ..) for this comment.

:kwns-alias would be used to establish namespace aliases for ::qualified/keywords

One open question is, how :kwns-alias should interact with alias. i.e. whether the namespace of ::qualified/keyword should always expand to the same as the one of a qualified/symbol or if they should be allowed to differ. I'd argue they should always be the same, because of the rule of simplicity. That means, that

  • alias will need to check if the sym is already in :kwns-alias and throw, if so
  • :kwns-alias will need to also work on `qualified/keywords probably shouldn't have knws in its name any more

So what's a good name for :kwns-alias? :let maybe?

Comment by Alex Miller [ 26/Sep/17 8:23 PM ]

beta = feature complete, so this isn't happening in 1.9.

I think adding anything to ns is likely off the table, but until I learn more about what Rich has in mind, I can't really suggest anything more.

Comment by Herwig Hochleitner [ 27/Sep/17 7:05 AM ]

that's a pity. but maybe 1.10 will have a shorter release time ...

In any case, I'll be very interested in Rich's idea to do this outside of the ns clause and still have it fit well with clojurescript (or even clojure, for that matter, ...)
Do you have any rationale, why growing ns for this is a bad idea?

Comment by Alex Miller [ 27/Sep/17 7:07 AM ]

ns already does way too much stuff and we don't have any desire to make it do more.

Comment by Herwig Hochleitner [ 27/Sep/17 12:20 PM ]

Since ns is essential to how a namespace is set up in clojure, I'd imagine a fix for that problem (of ns doing too much) to imply some rather drastic changes to the state of the art. As we won't break ns, I'd imagine either some sort of ns2 or a way to do namespace setup outside of the ns clause. I'm curious either way.

Since I know, that Rich will not be hassled about his hammock time, I'll lay off this for now. I'll be sure to check back as the next round of alphas goes out. I also hope for some productive discussion in the meantime.





[CLJ-2112] Add specs for spec forms Created: 15/Feb/17  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: Release 1.10

Type: Feature Priority: Major
Reporter: Alex Miller Assignee: Alex Miller
Resolution: Unresolved Votes: 18
Labels: spec

Attachments: Text File spec-forms.patch    
Approval: Incomplete

 Description   

It would be useful to have specs that described spec forms, such that it was possible to go from a spec form like (s/keys :req [::a ::b] :opt [::c]) to a conformed version that allowed you to grab the parts without parsing the s-expression. This can be done by creating specs, thus allowing:

user=> (require '[clojure.spec :as s] '[clojure.spec.specs])
user=> (s/def ::aspec (s/keys :req [::a ::b] :opt [::c]))
user=> (def aspec-data (s/conform :clojure.spec.specs/spec (s/form ::aspec)))
user=> (pr aspec-data)
[:form {:s clojure.spec/keys, 
        :args {:req [[:key :clojure.spec.specs/a] [:key :clojure.spec.specs/b]], 
               :opt [:clojure.spec.specs/c]}}]
user=> (map val (-> aspec-data val :args :req))
(:clojure.spec.specs/a :clojure.spec.specs/b)

Patch: spec-forms.patch (a work in progress)



 Comments   
Comment by Saul Shanabrook [ 05/Aug/17 6:08 PM ]

Could I help out on this? Happy to work on it. It would be very helpful for me, trying parse the the specs from the :args and :ret in fspec.

Comment by Alex Miller [ 06/Aug/17 11:05 PM ]

As you can see, there is an existing patch here with substantial work on it already (and some early review from Rich and Stu). The most useful help on this at the moment would be feedback on the gaps/open questions in it.

Comment by Alex Miller [ 06/Aug/17 11:17 PM ]

Also, I should mention that I do not expect this to be finalized and included until we have finalized the spec forms themselves as they are still subject to change.





[CLJ-1078] Add queue and queue? to clojure.core Created: 26/Sep/12  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Timothy Baldridge Assignee: Unassigned
Resolution: Unresolved Votes: 17
Labels: data-structures, queue

Attachments: File clj-1048-add-queue-functions.diff     Text File queue.patch    

 Description   

Add queue function to create queues from collections and queue? predicate to check queueness.

Patch: clj-1048-add-queue-functions.diff



 Comments   
Comment by Andy Fingerhut [ 28/Sep/12 8:43 AM ]

Timothy, I tried applying both of these Sep 26, 2012 patches to latest Clojure master as of that date. I had to apply 0001-make-PersistentQueue-ctor-public.patch by hand since it failed to apply using git or patch. It built fine, but failed to pass several of the Clojure tests. Have you looked into those test failures to see if you can find the cause and fix them? I tested on Ubuntu 11.10 with Oracle JDK 1.6 and 1.7, and saw similar failures with both.

Comment by Timothy Baldridge [ 26/Oct/12 5:23 PM ]

Fixed the patch. Tests pass, created the patch, applied it to a different copy of the source and the tests still pass. So this new patch should be good to go.

Comment by Andy Fingerhut [ 26/Oct/12 5:43 PM ]

Timothy, I'm not sure how you are getting successful results when applying this patch. Can you try the steps below and see what happens for you? I get errors trying to apply the patch with latest Clojure master as of Oct 26, 2012. Also please use the steps on the JIRA workflow page to create a git format patch (http://dev.clojure.org/display/design/JIRA+workflow under "Development" heading).

% git clone git://github.com/clojure/clojure.git
% cd clojure
% patch -p1 < queues.patch
patching file src/clj/clojure/core.clj
patching file src/jvm/clojure/lang/PersistentQueue.java
Hunk #1 FAILED at 32.
1 out of 1 hunk FAILED – saving rejects to file src/jvm/clojure/lang/PersistentQueue.java.rej
patching file test/clojure/test_clojure/data_structures.clj
Hunk #1 succeeded at 123 with fuzz 2.
Hunk #2 succeeded at 861 with fuzz 2.
Hunk #3 FAILED at 872.
1 out of 3 hunks FAILED – saving rejects to file test/clojure/test_clojure/data_structures.clj.rej
patching file test/clojure/test_clojure/java_interop.clj

Comment by Timothy Baldridge [ 26/Oct/12 6:08 PM ]

I was using git apply. I tried the method you show above, and now I'm seeing the same issues you show above.

Comment by Andy Fingerhut [ 26/Oct/12 6:26 PM ]

Just so you know, the preferred way to create and apply patches are the "git format-patch master --stdout > patch.txt" to create a patch (after doing the branching commands described on the JIRA workflow page to create a branch for your changes), and the "git am --keep-cr -s < patch.txt" to apply a patch. If a patch was created that way and applies cleanly with that command, then you are definitely good to go.

The "patch -p1 < patch.txt" command is just a secondary method sometimes used to try to apply patches that aren't in the format produced above, or have errors when applying using that method.

Comment by Timothy Baldridge [ 26/Oct/12 9:15 PM ]

Just so you know, the preferred way to create and apply patches are the "git format-patch master --stdout > patch.txt" to create a patch (after doing the branching commands described on the JIRA workflow page to create a branch for your changes), and the "git am --keep-cr -s < patch.txt" to apply a patch. If a patch was created that way and applies cleanly with that command, then you are definitely good to go.

The "patch -p1 < patch.txt" command is just a secondary method sometimes used to try to apply patches that aren't in the format produced above, or have errors when applying using that method.

Comment by Timothy Baldridge [ 26/Oct/12 9:16 PM ]

added patch

Comment by Andy Fingerhut [ 26/Oct/12 9:37 PM ]

That one applies cleanly and passes all tests. It should show up on the next list of prescreened patches. Thanks.

Comment by Rich Hickey [ 29/Nov/12 9:54 AM ]

we don't use the queue* convention elsewhere, e.g. vec and vector. I think queue should take a collection like vec and set. (queue [1 2 3]) could be made to 'adopt' the collection as front.

Comment by Andy Fingerhut [ 11/Dec/12 1:00 PM ]

Patch queue.patch dated Oct 26 2012 no longer applies cleanly after recent CLJ-1000 commits, but only because of one line of changed patch context. It still applies cleanly with "patch -p1 < queue.patch". Not bothering to update the stale patch given Rich's comments suggesting more substantive changes.

Comment by Steve Miner [ 06/Apr/13 8:06 AM ]

See also CLJ-976 (tagged literal support for PersistentQueue)

Comment by John Jacobsen [ 23/May/13 8:54 PM ]

Don't want to step on Timothy B's toes here, but it looks straightforward to adopt his patch to implement Rich's suggestion. I'd offer to give it a whack if nobody else wants the ticket now.

Comment by John Jacobsen [ 26/May/13 9:04 AM ]

Discussion initiated on clojure-dev: https://groups.google.com/forum/?fromgroups#!topic/clojure-dev/2BOqHm24Vc4

Comment by John Jacobsen [ 31/May/13 9:58 AM ]

This patch (if accepted) supersedes Timothy Baldridge's patch; it implements "queue" and "queue?" (but not "queue*"); "queue" accepts a collection rather than being a variadic function, as per Rich's suggestion.

Comment by Andy Fingerhut [ 30/Jan/14 5:00 PM ]

The patch clj-1048-queue-takes-collections.diff applied cleanly to latest Clojure master as of Jan 23 2014, but not on Jan 30 2014. There were several commits made to Clojure during that week involving updating the hash functions that conflict in some way with this patch. I have not checked to see how easy or difficult it might be to update the patch.

Comment by John Jacobsen [ 05/Feb/14 1:45 PM ]

Hi Andy, I updated the patch and removed my previous version. The new one should apply cleanly and pass all tests.

Comment by John Jacobsen [ 05/Feb/14 2:24 PM ]

Updated ticket title.

Comment by Alex Miller [ 05/Feb/14 5:33 PM ]

Hi John... Can you condense these changes into a single commit? Please also remove the comments above queue* in java_interop.clj. Thanks...

Comment by John Jacobsen [ 05/Feb/14 6:55 PM ]

Hi Alex, the updated patch removes that comment and rebases all three commits into c9f77dd. Let me know if you need anything else. Thanks!

Comment by Bozhidar Batsov [ 19/Oct/14 3:00 AM ]

A tiny remark - I think the docstrings should end with a dot.





[CLJ-1527] Clarify and align valid symbol and keyword rules for Clojure (and edn) Created: 18/Sep/14  Updated: 14/Dec/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Herwig Hochleitner Assignee: Unassigned
Resolution: Unresolved Votes: 16
Labels: reader

Approval: Triaged

 Description   

Known areas of under-specificity (http://clojure.org/reader#The%20Reader--Reader%20forms):

  • symbols (and keywords) description do not mention constituent characters that are currently in use by Clojure functions such as <, >, =, $ (for Java inner classes), & (&form and &env in macros), % (stated to be valid in edn spec)
  • keywords currently accept leading numeric characters which is at odds with the spec - see CLJ-1286

References:



 Comments   
Comment by Andy Fingerhut [ 17/Oct/14 2:13 AM ]

The Clojure reader documentation also does not mention the following symbols as valid constituent characters. They are all mentioned as valid symbol constituent characters in the EDN readme here: https://github.com/edn-format/edn#symbols

dollar sign - used in Clojure/JVM to separate Java subclass names from class names, e.g. java.util.Map$Entry
percent sign - not sure why this is part of edn spec. In Clojure it seems only to be used inside #() for args like % %1 %&
ampersand - like in &form and &env in macro definitions
equals - clojure.core/= and many others
less-than - clojure.core/< clojure.core/<=
greater-than - clojure.core/> clojure.core/>=

I don't know whether Clojure and edn specs should be the same in this regard, but it seemed worth mentioning for this ticket.

Comment by Andy Fingerhut [ 01/Jun/15 12:22 AM ]

Alex, Rich made this comment on CLJ-17 in 2011: "Runtime validation off the table for perf reasons. cemerick's suggestion that arbitrary symbol support will render them valid is sound, but arbitrary symbol support is a different ticket/idea." I am not aware of any tickets that propose the enhancement of allowing arbitrary symbols to be supported by Clojure, e.g. via a syntax like

#|white space and arbitrary #$@)$~))@ chars here|

Do you think it is reasonable to create an enhancement ticket for supporting arbitrary characters in symbols and keywords?

Comment by Alex Miller [ 01/Jun/15 6:36 AM ]

Sure. I looked into this a bit as a digression off of feature expressions and #| has been reserved for this potential use. However, there are many tricky issues with it and I do not expect this to happen soon - more likely to be something we're pushed to do when necessary for some other reason.

Comment by Herwig Hochleitner [ 01/Jun/15 8:46 AM ]

Wrong ticket, but to anybody thinking about #|arbitrary symbols (or strings)|, please do consider making the delimiters configurable, as in mime multipart.

Comment by Andy Fingerhut [ 01/Jun/15 8:54 AM ]

I've created a design page for now. I'm sure it does not list many of the tricky issues you have found. I'd be happy to take a shot at documenting them if you have any notes you are willing to share.

http://dev.clojure.org/pages/viewpage.action?pageId=11862058

Comment by Andy Fingerhut [ 01/Jun/15 9:01 AM ]

Herwig, can you edit the design page linked in my previous comment, to add a reference or example to precisely how mime multipart allows delimiters to be configurable, and why you believe fixed delimeters would be a bad idea?

Comment by Herwig Hochleitner [ 01/Jun/15 9:46 AM ]

I've commented on the design page.

Comment by Alex Miller [ 13/Jul/15 12:44 PM ]

Removed a couple of issues that have been clarified on the reader page and are no longer issues.

Comment by Nicola Mometto [ 13/Jul/15 12:45 PM ]

Related to CLJ-1530

Comment by Adam Frey [ 15/Jul/15 11:55 AM ]

Related to this: The Clojure reader will not accept symbols and keywords that contain consecutive colons (See LispReader.java), although that is permitted by the current EDN spec. Here is a GitHub issue regarding consecutive colons. I would like to qualify why consecutive colons are disallowed, and sync up the Clojure Reader and the EDN spec on this.

Comment by Herwig Hochleitner [ 31/Jul/15 8:03 AM ]

The updated reader spec says that a symbol can contain a single / to separate the namespace. It also mentions a bare / to be the division function.
So what about clojure.core//? That still got to be a readable symbol right? So is that an exception to the 'single /' rule?
Will foo.bar// also be readable? What about foo//bar?

Comment by Francis Avila [ 10/Sep/15 9:26 AM ]

Another source of ambiguity I see is that it's unclear whether the first colon of a keyword is the first character of the keyword (and therefore of the symbol) or whether it is something special and the spec really describes what happens from the second character onward. This matters because the specification for a keyword is (in both edn and reader specs) given in terms of differences from symbols. I think many of the strange keyword edge cases (including legality of :1 vs :a/1) stem from this ambiguity, and different tickets/patches seem to choose one or the other underlying assumption. See this comment for more examples.

Possibly we can use tagged literals for keywords and symbols to create or print these forms when they are not readable and simplify the reader spec for their literal forms. E.g. instead of producing complicated parse rules to ensure clojure.core// or :1 are legal, just make the literal form simple and have users write something like #sym["clojure.core" "/"] or #kyw "1" (and have the printer print these) when they hit these edge cases.

Comment by Alex Miller [ 10/Sep/15 9:44 AM ]

I would say : (and : are syntactic markers and the spec describes the characters following it. But I agree it would be nice for this to be more explicit. The (incorrect) regex in LispReader does not help either.

The tagged literal idea is an interesting alternative to the | | syntax that has been reserved for possible future support for invalid characters in keywords and symbols. But I think the idea is out of scope for this ticket, which is really about clarifying the spec.

Comment by Steven Yi [ 08/Nov/16 11:16 AM ]

Coming to this late, I had mentioned on the user mailing list in:

https://groups.google.com/forum/#!topic/clojure/CwZHu1Eszbk

that # is currently allowed as part of a symbol name, such that:

(let a# 4 b#a 3 (println a# b#a))

will print "4 3".

  1. is also employed in auto-gensyms and discussed in http://clojure.org/reference/reader#syntax-quote as part of a symbol's name. From the mailing list thread, # was noted as "may be allowed now, but could be changed later". I would appreciate if it is more clearly described as a special case/reserved, and would ask that its use be restricted in the reader to prevent users from using it now and potentially have code break later.




[CLJ-1107] 'get' should throw exception on non-Associative argument Created: 13/Nov/12  Updated: 14/Nov/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Stuart Sierra Assignee: Stuart Sierra
Resolution: Unresolved Votes: 16
Labels: checkargs

Attachments: Text File 0001-CLJ-1107-Throw-exception-for-get-called-on-unsupport.patch     Text File 0003-CLJ-1107-Throw-exception-for-get-on-unsupported-type.patch     Text File clj-1107-throw-on-unsupported-get-v4.patch    
Patch: Code and Test
Approval: Triaged

 Description   

The implementation of clojure.core/get returns nil if its argument is not an associative collection.

This behavior can obscure common programmer errors such as:

(def a (atom {:a 1 :b 2})

(:foo a)   ; forgot to deref a
;;=> nil

Calling get on something which is neither nil nor an Associative collection is almost certainly a bug, and should be indicated by an exception.

CLJ-932 was accepted as a similar enhancement to clojure.core/contains?

Patch: 0003-CLJ-1107-Throw-exception-for-get-on-unsupported-type.patch

Approach: Throw IllegalArgumentException as final fall-through case in RT.getFrom instead of returning nil.

Also see: CLJ-969



 Comments   
Comment by Andy Fingerhut [ 24/May/13 12:31 PM ]

Patch clj-1107-throw-on-get-for-unsupported-types-patch-v2.txt dated May 24 2013 is identical to 0001-CLJ-1107-Throw-exception-for-get-called-on-unsupport.patch dated Nov 13 2012, except it applies cleanly to latest master. A recent commit for CLJ-1099 changed many IllegalArgumentException occurrences to Throwable in the tests, which is the only thing changed in this updated patch.

Comment by Andy Fingerhut [ 30/Jan/14 5:01 PM ]

Patch clj-1107-throw-on-get-for-unsupported-types-patch-v2.txt applied cleanly to latest Clojure master as of Jan 23 2014, but no longer does with commits made to Clojure between then and Jan 30 2014. I have not checked to see how difficult or easy it may be to update this patch.

Comment by Stuart Sierra [ 11/Feb/14 7:23 AM ]

New patch 0003-CLJ-1107-Throw-exception-for-get-on-unsupported-type.patch created from master at 5cc167a.

Comment by Andy Fingerhut [ 26/Mar/14 11:55 AM ]

Patch clj-1107-throw-on-unsupported-get-v4.patch dated Mar 26 2014 is identical to Stuart Sierra's patch 0003-CLJ-1107-Throw-exception-for-get-on-unsupported-type.patch, and retains his authorship. The only difference is in one line of diff context required in order to make it apply cleanly to latest master.

Comment by Rich Hickey [ 10/Jun/14 10:54 AM ]

This would be a breaking change

Comment by Stuart Sierra [ 17/Jun/14 6:59 PM ]

Arguably so was CLJ-932 (contains?), which did "break" some things that were already broken.

This is a more invasive change than CLJ-932, but I believe it is more likely to expose hidden bugs than to break intentional behavior.

Comment by Andy Sheldon [ 07/Oct/14 5:40 AM ]

Is it more idiomatic to use "({:a 1}, :a)" and a safe replacement to boot? E.g. could you mass replace "(get " with "(" in a code base, in order to find bugs? I am still learning the language, and not young anymore, and couldn't reliably remember the argument order. So, I found it easier to avoid (get) with maps anyways. Without it I can put the map first or second.

Comment by Alex Miller [ 14/Nov/16 12:11 PM ]

Presumably this could also now be accomplished via a spec on "get".





[CLJ-440] java method calls cannot omit varargs Created: 27/Sep/10  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Critical
Reporter: Alexander Taggart Assignee: Ragnar Dahlen
Resolution: Unresolved Votes: 15
Labels: interop

Attachments: Text File 0001-CLJ-440-Allow-calling-vararg-Java-methods-without-va.patch    
Approval: Triaged

 Description   

Problem

Clojure calls to Java vararg methods require creating an object array for the final arg. This is a frequent source of confusion when doing interop.

E.g., trying to call java.util.Collections.addAll(Collection c, T... elements):

user=> (Collections/addAll [] (object-array 0))
false
user=> (Collections/addAll [])
IllegalArgumentException No matching method: addAll  clojure.lang.Compiler$StaticMethodExpr.<init> (Compiler.java:1401)

The Method class provides an isVarArg() method, which could be used to inform the compiler to process things differently.

From http://groups.google.com/group/clojure/browse_thread/thread/7d0d6cb32656a621

Latest patch: Removed because incomplete and goal not clear

Varargs in Java

As currently stated, the scope of this ticket is only to omit varargs, but this is only one case where Clojures handling of varargs differs from Java. For completeness, here is a brief survey of how Java handles vararg methods, which could hopefully inform a discussion for how Clojure could do things differently, and what the goal of this ticket should be.

Given the following setup:

VarArgs.java
public class VarArgs {

    public static class SingleVarargMethod {
        public static void m(String arg1, String... args) {}
    }

    public static class MultipleVarargMethods {
        public static void m(String... args) {}
        public static void m(String arg1) {}
        public static void m(String arg1, String... args) {}
    }
}
Java Possible clojure equivalent? Comments
VarArgs.SingleVarargMethod.m("a"); (SingleVarargMethod/m "a")  
VarArgs.SingleVarargMethod.m("a", "b"); (SingleVarargMethod/m "a" "b")  
VarArgs.SingleVarargMethod.m("a", "b", "c"); (SingleVarargMethod/m "a" "b" "c")  
VarArgs.SingleVarargMethod.m("a", new String[]{"b", "c"}); (SingleVarargMethod/m "a" (object-array ["b" "c"]))  
VarArgs.MultipleVarargMethods.m(); (MultipleVarargMethods/m)  
VarArgs.MultipleVarargMethods.m((String) null); (MultipleVarargMethods/m nil) Use type hints to disambiguate?
VarArgs.MultipleVarargMethods.m((String[]) null); (MultipleVarargMethods/m nil) Use type hints to disambiguate?
VarArgs.MultipleVarargMethods.m("a", null); (MultipleVarargMethods/m "a" nil)  
VarArgs.MultipleVarargMethods.m("a", new String[]{}); (MultipleVarargMethods/m "a" (object-array 0))  
VarArgs.MultipleVarargMethods.m(new String[]{"a"}); (MultipleVarargMethods/m (object-array ["a"]))  
VarArgs.MultipleVarargMethods.m("a", new String[]{"b", "c"}); (MultipleVarargMethods/m "a" (object-array ["b" "c"]))  


 Comments   
Comment by Assembla Importer [ 27/Sep/10 8:19 PM ]

Converted from http://www.assembla.com/spaces/clojure/tickets/440

Comment by Alexander Taggart [ 01/Apr/11 11:16 PM ]

Patch adds support for varargs. Builds on top of patch in CLJ-445.

Comment by Alexander Taggart [ 05/Apr/11 5:45 PM ]

Patch updated to current CLJ-445 patch.

Comment by Nick Klauer [ 29/Oct/12 8:12 AM ]

Is this ticket on hold? I find myself typing (.someCall arg1 arg2 (into-array SomeType nil)) alot just to get the right method to be called. This ticket sounds like it would address that extraneous into-array arg that I use alot.

Comment by Andy Fingerhut [ 29/Oct/12 10:45 AM ]

fixbug445.diff uploaded on Oct 29 2012 was written Oct 23 2010 by Alexander Taggart. I am simply copying it from the old Assembla ticket tracking system to here to make it more easily accessible. Not surprisingy, it doesn't apply cleanly to latest master. I don't know how much effort it would be to update it, but only a few hunks do not apply cleanly according to 'patch'. See the "Updating stale patches" section on the JIRA workflow page here: http://dev.clojure.org/display/design/JIRA+workflow

Comment by Andy Fingerhut [ 29/Oct/12 10:56 AM ]

Ugh. Deleted the attachment because it was for CLJ-445, or at least it was named that way. CLJ-445 definitely has a long comment history, so if one or more of its patches address this issue, then you can read the discussion there to see the history.

I don't know of any "on hold" status for tickets, except for one or two where Rich Hickey has explicitly said in a comment that he wants to wait a while before making the change. There are just tickets that contributors choose to work on and ones that screeners choose to screen.

Comment by Alex Miller [ 02/Feb/16 11:47 AM ]

I would love to see an updated patch on this ticket that specifically addressed the varargs issue without building on the other mentioned ticket and patch (which is of lower priority).

Comment by Ragnar Dahlen [ 03/Feb/16 8:01 AM ]

I had a stab at this, have attached an initial patch, parts of which I'm not too sure/happy about so feedback would be appreciated.

The patch takes the following approach:

  1. Teach Reflector/getMethods how to find matching vararg methods. In addition to the current constraints, a method can also match if it is a varargs method, and the arity of the method is one more than the requested arity. That means it's a varargs method we could call, but the user hasn't provided the varargs argument.
  2. In MethodExpr/emitTypedArgs we handle the case were there is one more argument in the method being called than there were arguments provided. The only case were that should happen is when it is a varargs method and the last argument was not provided. In that case we push a new empty object array to the stack.

I'm not to sure about my implementation of the second part. It could open up for some hard to understand bugs in the future. One option would be to be more defensive, and make sure it's really the last argument for instance, or even pass along the Method object (or a varargs flag) so we know what we can expect and need to do.

Comment by Ragnar Dahlen [ 03/Feb/16 8:49 AM ]

I realised my patch is missing two important cases; the interface handling in Reflector and handling multiple matching methods. I'll look into that too, but would still appreciate feedback on the approach in MethodExpr/emitTypedArgs.

Comment by Alex Miller [ 03/Feb/16 9:00 AM ]

I am in favor of using isVarArg() to explicitly handle this case rather than guessing if we're in this situation. We should check the behavior (and add tests where it seems needed) for calling a var args method with too few args, too many args, etc. And also double-check that non vararg cases have not changed behavior.

Also, keep in mind that as a general rule, existing AOT compiled code may rely on calling into public Reflector methods, so if you change the signatures of public Reflector methods, you should leave a version with the old arity that has some default behavior for backwards compatibility.

Comment by Ghadi Shayban [ 21/Apr/17 11:31 AM ]

Any extra logic that the compiler implements will need to distinguish between:

public static class MultipleVarargMethods {
        public static void m(String... args) {}
        public static void m(String arg1, String... args) {}
    }

which I don't think is possible generically, without breaking code.

Rather than omitting varargs, how about handling them without tedious array construction. An alternative is to introduce new explicit sugar that you have to opt-in to:

(Whatever/varargs a b c ... x y z)

where ... or similar would be understood by StaticMethodExpr or InstanceMethodExpr in the compiler, and could be type-hinted to resolve ambiguity. This would not be a breaking change.

Comment by Phill Wolf [ 27/Apr/17 6:58 PM ]

If javac can tell the methods apart without the caller providing a "..." partition, so should Clojure. (But in the specific "MultipleVarargMethods" class, javac can't distinguish:

public class MultipleVarargMethods {
    public static void m(String... args) {}
    public static void m(String arg1, String... args) {}
    public static void main(String [] args) {
        m("bankruptcy");
        m("bankruptcy","in","progress");
    }
}


MultipleVarargMethods.java:5: error: reference to m is ambiguous
        m("bankruptcy");
        ^
  both method m(String...) in MultipleVarargMethods and method m(String,String...) in MultipleVarargMethods match
MultipleVarargMethods.java:6: error: reference to m is ambiguous
        m("bankruptcy","in","progress");
        ^
  both method m(String...) in MultipleVarargMethods and method m(String,String...) in MultipleVarargMethods match
2 errors

)





[CLJ-1550] Classes generated by deftype and defrecord don't play nice with .getPackage Created: 07/Oct/14  Updated: 14/Nov/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6, Release 1.7, Release 1.8
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: Bozhidar Batsov Assignee: Unassigned
Resolution: Unresolved Votes: 15
Labels: classloader, deftype

Attachments: Text File 0001-CLJ-1550-define-package-for-class-in-DynamicClassLoa.patch     Text File CLJ-1550-v2.patch     Text File clj-1550-v3.patch    
Patch: Code and Test
Approval: Prescreened

 Description   

Classes generated loaded by DynamicClassLoader return nil for .getPackage. Tools like CIDER and vim-fireplace are relying on this information to implement things like completion hints.

(.getPackage String)
;; => #<Package package java.lang, Java Platform API Specification, version 1.7>
(deftype T [])
(.getPackage T)
;; => nil

Proposed: During DynamicClassLoader.defineClass(), invoke definePackage() on the class being defined (similar to what URLClassLoader does).

Patch: clj-1550-v3.patch

Prescreened by: Alex Miller



 Comments   
Comment by Alex Miller [ 07/Oct/14 8:54 AM ]

According to http://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#getPackage() this method returns the package information found by the class loader or null if there is none. Its not clear to me that the current behavior is wrong per the spec. I would need to experiment more to see if this is unusual or not.

Comment by Bozhidar Batsov [ 07/Oct/14 9:05 AM ]

A bit of background for the issue. I'm no expert on the topic, but being able to procure all the class information except its package definitely looks strange to me.

Comment by Kevin Downey [ 07/Oct/14 11:46 AM ]

if you AOT compile(generate a class file on disk for a deftype), getPackage works fine, which suggests to me it is a jvm issue

Comment by Kevin Downey [ 07/Oct/14 11:49 AM ]

actually, it must just be that dynamicclassloader doesn't define a package for classes it loads

Comment by Alex Miller [ 07/Oct/14 12:13 PM ]

Yep, I believe that's correct.

Comment by Stuart Halloway [ 21/Jul/15 8:01 AM ]

There is no problem statement here. What is package information needed for?

Comment by Bozhidar Batsov [ 21/Jul/15 8:05 AM ]

I've linked the problem above. Basically tools like CIDER and vim-fireplace are relying on this information to implement things like completion hints.
This might not be problem when running your apps, but it's definitely a problem when inspecting their state...

Comment by Michael Blume [ 22/Jul/15 12:32 PM ]

s/Packate/Package

Comment by Alex Miller [ 14/Nov/16 12:10 PM ]

Refreshed patch to apply to current master, attribution retained, no semantic changes. Marked prescreened.





[CLJ-1063] Missing dissoc-in Created: 07/Sep/12  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.4
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Gunnar Völkel Assignee: Unassigned
Resolution: Unresolved Votes: 14
Labels: None

Attachments: File 001-dissoc-in.diff     Text File clj-1063-add-dissoc-in-patch-v2.txt    
Approval: Triaged

 Description   

There is no clojure.core/dissoc-in although there is an assoc-in.
It is correct that dissoc-in can be build with update-in and dissoc but this is an argument against assoc-in as well.
When a shortcut for assoc-in is provided, there should also be one for dissoc-in for consistency reasons.
Implementation is analogical to assoc-in.



 Comments   
Comment by Andy Fingerhut [ 13/Sep/12 2:17 PM ]

Patch clj-1063-add-dissoc-in-patch-v2.txt dated Sep 13 2012 supersedes 001-dissoc-in.diff dated Sep 7 2012. It fixes a typo (missing final " in doc string), and adds a test case for the new function.

Comment by Nicola Mometto [ 13/Sep/12 2:27 PM ]

Thanks for the fix Andy

Comment by Andy Fingerhut [ 14/Sep/12 8:24 PM ]

This proposed dissoc-in should be compared with the one in clojure.core.incubator which I just happened across. I see they look different, but haven't examined to see if there are any behavior differences.

https://github.com/clojure/core.incubator/blob/master/src/main/clojure/clojure/core/incubator.clj

Comment by Nicola Mometto [ 15/Sep/12 6:43 AM ]

dissoc-in in clojure.core.incubator recursively removes empty maps

user=> (clojure.core.incubator/dissoc-in {:a {:b {:c 1}}} [:a :b :c])
{}

while the one in this patch doesn't (as I would expect)

user=> (dissoc-in {:a {:b {:c 1}}} [:a :b :c])
{:a {:b {}}}

Comment by Stuart Halloway [ 17/Sep/12 7:04 AM ]

Please do this work in the incubator.

Comment by Andrew Rosa [ 30/Jun/15 9:09 AM ]

Keeping the empty paths is really the most expected thing to do? I say, since both assoc-in/update-in create paths along the way this behavior looks to be the real "dual".

What kind of bad things could happen that nil punning does not deal well with it? Those issues would be too much obscure for dissoc-in user's point of view?

Comment by Alex Miller [ 19/Oct/15 10:21 PM ]

Tests are much too light in the patch. Should test multiple levels, records, vectors, etc.

Comment by Daniel Compton [ 21/Oct/15 4:16 PM ]

Testing "clj-1063-add-dissoc-in-patch-v2.txt"

(dissoc-in {} [:a :b :c])
=> {:a {:b nil}}

this behaviour is pretty unexpected. The incubator version doesn't have this problem, though it does remove empty maps.

I'm working on tests (and possibly a new dissoc-in) for this patch, but I'm not clear yet whether empty paths should be kept or removed? I don't mind either way, though I tend to agree with Andrew Rosa that keeping them is more symmetrical.

Comment by Daniel Compton [ 16/May/16 4:12 PM ]

@alex, do you want empty paths to be kept or removed? Either way is acceptable, though on balance I slightly prefer leaving them. I can work up tests for this, once I know which direction you want to go in.

Comment by Alex Miller [ 17/May/16 6:46 AM ]

What are the tradeoffs of one vs the other?

In places where people are using dissoc-in stand-ins (update-in with dissoc etc) what behavior are they expecting?

Comment by Michał Marczyk [ 17/May/16 12:31 PM ]

If we only wanted to handle maps nested in maps …, I'd probably prefer removing empty subpaths.

However, if we want to admit vectors along the way, then leaving empty paths in place makes for pretty clear semantics in that case:

(dissoc-in [{:foo 1}] [0 :foo])
;= [{}]

In contrast, removing empty paths would seem to lead to problems that would have to be resolved either by limiting the path-removing behaviour to maps or throwing when a subpath nested in a vector becomes entry. Either approach seems suboptimal.

Comment by Michał Marczyk [ 17/May/16 12:38 PM ]

Also we could technically accept a flag to decide whether empty paths should be removed and let the user ensure that they only pass true if there are no vectors in the way. I'm not sure I like this approach very much, though, because it seems to me that the more natural purpose for extra arguments is to provide additional paths to dissoc for matching variadic dissoc and dissoc-in semantics (cf. CLJ-1771).

Comment by Alex Miller [ 18/May/16 8:12 AM ]

We must consider vectors or associative data structures other than maps. I also would prefer not to have a flag and to instead leave it open for variadic to remove multiple.

With an equivalent like:

(update-in [{:foo 1}] [0] dissoc :foo)

we would be left with [{}] so the existing way to do this does leave empty collections.

I also looked at some of the existing dissoc-in implementations that already exist - core.incubator, taoensso.encore, clj-http, medley, useful, plumbing, etc. Most work with a single key-path and leave empty collections - these seem largely to derive from the incubator version. The encore one works with multiple paths by separating the key path from the final leaf keys to dissoc (variadic). The medley, useful, and plumbing ones are map-only and remove empty maps.

I can't imagine that we would make a map-specific version of this in core (since all the other -in functions are generic) and thus I conclude that we would need a dissoc-in that left empty collections. Given that, I'm not sure whether dissoc-in provides enough value over update-in + dissoc to be worth adding to core at this point, especially since it exists in a variety of utility libraries (in many cases with differing semantics). We are then potentially breaking (or at least inconveniencing) many users of existing dissoc-in impls. I'm going to leave this open for comments, but I'm of a mind to decline this enhancement at this point.

Comment by Nicola Mometto [ 18/May/16 8:33 AM ]

The same argument could've been made for the inclusion of `update`. The fact that both `update` and `dissoc-in` can be found in several util libraries should indicate that people are not ok with just using `update-in` + `dissoc`.

Sure adding it to core is going to cause warnings when using some libraries (it's not going to break anything, the AOT bugs that caused breakages with `update` have been fixed) but I don't think that's really a big deal; new versions of those libraries will get released quickly and even if that's not the case a warning is not the end of the world.

Comment by Alex Miller [ 18/May/16 9:05 AM ]

True, although I'd say the factors balance differently in the update case. With update there fewer implementations and they matched what we were proposing to add. So, they created the potential for the existing ones to be replaced with a core function.

I think the common utility library impls (flatland/useful/plumbing) are actually covering a need that is different - update-in + dissoc + path removal on maps only. So if the goal is to cover a common usage, then we would need to have it work only on maps and remove empty paths left behind. However, I think that is somewhat at odds with the other core -in functions. I guess maybe there is a middle ground to do path removal but make it work beyond maps - that would satisfy the needs indicated by the utility libs but also be generic like the other -in functions. And if you needed to leave the empty colls, you could do what you do now - update-in+dissoc.





[CLJ-1005] Use transient map in zipmap Created: 30/May/12  Updated: 19/Jul/15

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Michał Marczyk Assignee: Unassigned
Resolution: Unresolved Votes: 14
Labels: ft, performance

Attachments: Text File 0001-Use-transient-map-in-zipmap.2.patch     Text File 0001-Use-transient-map-in-zipmap.patch     Text File 0002-CLJ-1005-use-transient-map-in-zipmap.patch     Text File CLJ-1005-zipmap-iterators.patch    
Patch: Code
Approval: Vetted

 Description   

#'zipmap constructs a map without transients, where transients could improve performance.

Approach: Use a transient map internally, along with iterators for the keys and values. A persistent map is returned as before. The definition is also moved so that it resides below that of #'transient.

Performance:

(def xs (range 16384))
(def ys (range 16))

expression 1.7.0-beta3 +patch  
(zipmap xs xs) 4.50 ms 2.12 ms large map
(zipmap ys ys) 2.75 us 2.07 us small map

Patch: CLJ-1005-zipmap-iterators.patch

Screened by: Alex Miller



 Comments   
Comment by Aaron Bedra [ 14/Aug/12 9:24 PM ]

Why is the old implementation left and commented out? If we are going to move to a new implementation, the old one should be removed.

Comment by Michał Marczyk [ 15/Aug/12 4:17 AM ]

As mentioned in the ticket description, the previously attached patch follows the pattern of into whose non-transient-enabled definition is left in core.clj with a #_ in front – I wasn't sure if that's something desirable in all cases.

Here's a new patch with the old impl removed.

Comment by Andy Fingerhut [ 15/Aug/12 10:37 AM ]

Thanks for the updated patch, Michal. Sorry to raise such a minor issue, but would you mind using a different name for the updated patch? I know JIRA can handle multiple attached files with the same name, but my prescreening code isn't quite that talented yet, and it can lead to confusion when discussing patches.

Comment by Michał Marczyk [ 15/Aug/12 10:42 AM ]

Thanks for the heads-up, Andy! I've reattached the new patch under a new name.

Comment by Andy Fingerhut [ 16/Aug/12 8:24 PM ]

Presumptuously changing Approval from Incomplete back to None after the Michal's updated patch was added, addressing the reason the ticket was marked incomplete.

Comment by Aaron Bedra [ 11/Apr/13 5:32 PM ]

The patch looks good and applies cleanly. Are there additional tests that we should run to verify that this is providing the improvement we think it is. Also, is there a discussion somewhere that started this ticket? There isn't a lot of context here.

Comment by Michał Marczyk [ 11/Apr/13 6:19 PM ]

Hi Aaron,

Thanks for looking into this!

From what I've been able to observe, this change hugely improves zipmap times for large maps. For small maps, there is a small improvement. Here are two basic Criterium benchmarks (transient-zipmap defined at the REPL as in the patch):

;;; large map
user=> (def xs (range 16384))
#'user/xs
user=> (last xs)
16383
user=> (c/bench (zipmap xs xs))
Evaluation count : 13920 in 60 samples of 232 calls.
             Execution time mean : 4.329635 ms
    Execution time std-deviation : 77.791989 us
   Execution time lower quantile : 4.215050 ms ( 2.5%)
   Execution time upper quantile : 4.494120 ms (97.5%)
nil
user=> (c/bench (transient-zipmap xs xs))
Evaluation count : 21180 in 60 samples of 353 calls.
             Execution time mean : 2.818339 ms
    Execution time std-deviation : 110.751493 us
   Execution time lower quantile : 2.618971 ms ( 2.5%)
   Execution time upper quantile : 3.025812 ms (97.5%)

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 2 (3.3333 %)
 Variance from outliers : 25.4675 % Variance is moderately inflated by outliers
nil

;;; small map
user=> (def ys (range 16))
#'user/ys
user=> (last ys)
15
user=> (c/bench (zipmap ys ys))
Evaluation count : 16639020 in 60 samples of 277317 calls.
             Execution time mean : 3.803683 us
    Execution time std-deviation : 88.431220 ns
   Execution time lower quantile : 3.638146 us ( 2.5%)
   Execution time upper quantile : 3.935160 us (97.5%)
nil
user=> (c/bench (transient-zipmap ys ys))
Evaluation count : 18536880 in 60 samples of 308948 calls.
             Execution time mean : 3.412992 us
    Execution time std-deviation : 81.338284 ns
   Execution time lower quantile : 3.303888 us ( 2.5%)
   Execution time upper quantile : 3.545549 us (97.5%)
nil

Clearly the semantics are preserved provided transients satisfy their contract.

I think I might not have started a ggroup thread for this, sorry.

Comment by Andy Fingerhut [ 03/Sep/14 8:10 PM ]

Patch 0001-Use-transient-map-in-zipmap.2.patch dated Aug 15 2012 does not apply cleanly to latest master after some commits were made to Clojure on Sep 3 2014.

I have not checked whether this patch is straightforward to update. See the section "Updating stale patches" at http://dev.clojure.org/display/community/Developing+Patches for suggestions on how to update patches.

Comment by Michał Marczyk [ 14/Sep/14 12:48 PM ]

Thanks, Andy. It was straightforward to update – an automatic rebase. Here's the updated patch.

Comment by Ghadi Shayban [ 22/Sep/14 9:58 AM ]

New patch using clojure.lang.RT/iter, criterium shows >30% more perf in the best case. Less alloc probably but I didn't measure. CLJ-1499 (better iterators) is related





[CLJ-1293] Support (try .. (catch :default _ ..)) for portable "catch-all" Created: 05/Nov/13  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Brandon Bloom Assignee: Unassigned
Resolution: Unresolved Votes: 13
Labels: portability

Attachments: Text File CLJ-1293-v001.patch     Text File CLJ-1293-v002.patch     Text File CLJ-1293-v003.patch    
Approval: Triaged

 Description   

Clojurescript has this to expose the untyped catch, which is equivalent to (catch Throwable _) on java.

http://dev.clojure.org/jira/browse/CLJS-661

Proposals

1) add (catch :default _) to mean (catch Throwable _)
2) add (catch :default _) to mean (catch Exception _)
3) add (catch :all _) to mean (catch Throwable _)

Please see design page for discussion of proposals: http://dev.clojure.org/display/design/Platform+Errors

Patches

v001 implements just 1)

This patch is more permissive than my patch for CLJS: The CLJS patch ensures :default catch blocks occur between non-default catch blocks and finally blocks, if present. This patch just makes (catch :default ...) a synonym for (catch Throwable ...). I wanted to keep the change to the compiler minimum.

Open Question: Catch Throwable (patch v001 does this) or Exception? Alternatively, a more carefully crafted list of "non-fatal" errors. See Scala's NonFatal pattern extractor: http://www.scala-lang.org/api/current/scala/util/control/NonFatal$.html

v002 implements 2) + 3)

This builds on v001, so the same caveat about clause ordering applies.

v003 implements just 2)

This builds on v001, so the same caveat about clause ordering applies.



 Comments   
Comment by Brandon Bloom [ 28/Dec/14 11:33 AM ]

Noticed this switched from "Minor" to "Critical", so I figured I should mention that I later realized that we might want :default to catch Exception instead of Throwable, so as to avoid catching Error subclasses. Javadocs say: "An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch." If that's what we actually want, I can provide an updated patch.

Comment by Alex Miller [ 28/Dec/14 2:19 PM ]

Seems like an open question, might be best just to list it as such in the description.

I don't really expect to reach consensus on the ticket or patch right now, just trying to update priorities and raise visibility for discussion with Rich once we get to 1.8.

Comment by Herwig Hochleitner [ 07/Dec/16 4:15 PM ]

I'm in favor of catching Exception. It is the :default on java (as stated in the docs), so catching Throwable is a platform-specific thing to do and it would still be possible.

Comment by Herwig Hochleitner [ 07/Dec/16 5:08 PM ]

Hm, realizing now, that my last comment is at odds with the design discussion about being able to catch anything in javascript.

Attached patch v002 implements :all in addition to :default.

Comment by Herwig Hochleitner [ 07/Dec/16 6:30 PM ]

Realized, that catch-all vs catch-Exception is only a shallow contradiction: (catch Exception _) is - for all intents and purposes - the catch-all of java. Since the catch-absolutely-all is accessible in java through a regular catch, the driving need in clojurescript doesn't apply to clojure. The driving need in clojure is portability. In clojurescript, this is conflated with exposing an otherwise inaccessible platform feature, but that needs to not drive the general design.

Attached v003





[CLJ-1255] Support Abstract Base Classes with Java-only variant of "reify" Created: 06/Sep/13  Updated: 12/Dec/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Mike Anderson Assignee: Unassigned
Resolution: Unresolved Votes: 13
Labels: interop

Attachments: Text File 0001-CLJ-1225-add-defclass-extend-class.patch     Text File 0001-CLJ-1225-add-defclass-extend-class-v2.patch    
Approval: Triaged

 Description   

Problem:

  • Various Java APIs depend on extension of abstract base classes rather than interfaces
  • "proxy" has limitations (no access to protected fields or super)
  • "proxy" has performance overhead because of an extra layer of functions / parameter boxing etc.
  • "gen-class" is complex and is complected with compilation / bytecode generation

In summary: Clojure does not currently have a good / convenient way to extend a Java abstract base class dynamically.

The proposal is to create a variant of "reify" that allows the extension of a single abstract base class (optionally also with interfaces/protocols). Code generation would occur as if the abstract base class had been directly extended in Java (i.e. with full access to protected members and with fully type-hinted fields).

Since this is a JVM-only construct, it should not affect the portable extension methods in Clojure (deftype etc.). We propose that it is placed in an separate namespace that could become the home for other JVM-specific interop functionality, e.g. "clojure.java.interop"

Proposed solution: The attached patch proposes an implementation for this feature, providing a new `clojure.interop` namespace, containing the `defclass` and `extend-class` macros.

"(defclass name [fields*] options* super-class super-args specs*)

   Like clojure.core/deftype but can extend a concrete class, override
   and invoke public and protected methods defined in the super class or
   one of its base classes and access/set! public and protected fields of
   those.

   super-args is a (possibly empty) vector of arguments to the superclass
   constructor

   It is possible to invoke a super method while overriding it, by type-hinting
   the parameter `this` as the super class: (. ^SuperClass this method args*)"
"(extend-class options* super-class super-args specs*)

   Like clojure.core/reify but can extend a concrete class, override
   and invoke public and protected methods defined in the super class or
   one of its base classes and access/set! public and protected fields of
   those.

   super-args is a (possibly empty) vector of arguments to the superclass
   constructor

   It is possible to invoke a super method while overriding it, by type-hinting
   the parameter `this` as the super class: (. ^SuperClass this method args*)"

Patch: 0001-CLJ-1225-add-defclass-extend-class-v2.patch



 Comments   
Comment by Alex Miller [ 30/Jun/14 8:18 AM ]

From Rich: we do not want to support abstract classes in a portable construct (reify, deftype). However, this would be considered as a new Java-only construct (extend-class or reify-class). If you could modify the ticket appropriately, will move back to Triaged.

Comment by Nicola Mometto [ 15/May/17 3:19 PM ]

Attached a proposed impl for this feature

Comment by Nicola Mometto [ 15/May/17 3:22 PM ]

More documentation about the proposed impmlementation can be found at https://docs.google.com/document/d/1OcewjSpxmeFRQ3TizcaRRwlV34T8wl4wVED138FHFFE, non squashed commits at https://github.com/clojure/clojure/compare/master...Bronsa:defclass

Comment by Nicola Mometto [ 12/Dec/17 11:29 AM ]

Updated patch is the same as v1 but refreshed on top of master





[CLJ-308] protocol-ize with-open Created: 21/Apr/10  Updated: 14/Dec/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Assembla Importer Assignee: Unassigned
Resolution: Unresolved Votes: 13
Labels: io

Attachments: Text File 0001-Added-ClosableResource-protocol-for-with-open.patch    
Patch: Code
Approval: Triaged

 Description   

Good use (and documentation example) of protocols: make with-open aware of a Closable protocol for APIs that use a different close convention. See http://groups.google.com/group/clojure/browse_thread/thread/86c87e1fc4b1347c



 Comments   
Comment by Assembla Importer [ 24/Aug/10 4:39 PM ]

Converted from http://www.assembla.com/spaces/clojure/tickets/308

Comment by Tassilo Horn [ 23/Dec/11 5:11 AM ]

Added a CloseableResource protocol and extended it on java.io.Closeable (implemented by all Readers, Writers, Streams, Channels, Sockets). Use it in with-open.

All tests pass.

Comment by Tassilo Horn [ 23/Dec/11 7:14 AM ]

Seems to be related to Scopes (http://dev.clojure.org/jira/browse/CLJ-2).

Comment by Tassilo Horn [ 08/Mar/12 3:59 AM ]

Updated patch.

Comment by Andy Fingerhut [ 02/Apr/12 12:11 PM ]

Patch 0001-Added-ClosableResource-protocol-for-with-open.patch dated 08/Mar/12 applies, builds, and tests cleanly on latest master as of Apr 2 2012. Tassilo has signed a CA.

Comment by Tassilo Horn [ 13/Apr/12 11:23 AM ]

Updated patch to apply cleanly against master again.

Comment by Brandon Bloom [ 22/Jul/14 9:00 PM ]

I looked up this ticket because I ran in to a reflection warning: with-open does not hint it's binding with java.io.Closeable

Some feedback on the patch:

1) This is a breaking change for anyone relying on the close method to be duck-typed.

2) CloseableResource is a bit long. clojure.core.protocols.Closeable is plenty unambiguous.

3) Rather than extending CloseableResource to java.io.Closeable, you can use the little known (undocumented? unsupported?) :on-interface directive:

(defprotocol Closeable
  :on-interface java.io.Closeable
  (close [this]))

That would perform much better than the existing patch.

Comment by Tassilo Horn [ 23/Jul/14 7:12 AM ]

Hi Brandon, two questions:

Could 1) be circumvented somehow by providing a default implementation somehow? I guess the protocol could be extended upon Object with implementation (.close this), but that would give a reflection warning since Object has no close method. Probably one could extend upon Object and in the implementation search a "close" method using java.lang.reflect and throw an exception if none could be found?

Could you please tell me a bit more about the :on-interface option? How does that differ from extend? And how do I add the implementation, i.e., (.close this) with that option?





[CLJ-124] GC Issue 120: Determine mechanism for controlling automatic shutdown of Agents, with a default policy and mechanism for changing that policy as needed Created: 17/Jun/09  Updated: 23/Aug/14

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5, Release 1.6
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: Chas Emerick Assignee: Alex Miller
Resolution: Unresolved Votes: 13
Labels: agents

Attachments: Text File clj-124-daemonthreads-v1.patch     Text File clj-124-v1.patch    
Patch: Code
Approval: Vetted
Waiting On: Rich Hickey

 Description   

The original description when this ticket was vetted is below, starting with "Reported by cemer...@snowtide.com, June 01, 2009". This prefix attempts to summarize the issue and discussion.

Description:

Several Clojure functions involving agents and futures, such as future, pmap, clojure.java.shell/sh, and a few others, create non-daemon threads in the JVM in an ExecutorService called soloExecutor created via Executors#newCachedThreadPool. The javadocs for this method here http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Executors.html#newCachedThreadPool%28%29 say "Threads that have not been used for sixty seconds are terminated and removed from the cache." This causes a 60-second wait after a Clojure program is done before the JVM process exits. Questions about this confusing behavior come up a couple of times per year on the Clojure Google group. Search for "shutdown-agents" to find most of these occurrences, since calling (shutdown-agents) at the end of one's program typically eliminates this 60-second wait.

Example:

% java -cp clojure.jar clojure.main -e "(println 1)"
1
[ this case exits quickly ]

% java -cp clojure.jar clojure.main -e "(println @(future 1))"
1
[ 60-second pause before process exits, at least on many platforms and JVMs ]

Summary of comments before July 2014:

Most of the comments on this ticket on or before August 23, 2010 were likely spread out in time before being imported from the older ticket tracking system into JIRA. Most of them refer to an older suggested patch that is not in JIRA, and compilation problems it had with JDK 1.5, which is no longer supported by Clojure 1.6.0. I think these comments can be safely ignored now.

Alex Miller blogged about this and related issues here: http://tech.puredanger.com/2010/06/08/clojure-agent-thread-pools/

Since then, two of the suggestions Alex raised have been addressed. One by CLJ-378 and one by the addition of set-agent-send-executor! and similar functions to Clojure 1.5.0: https://github.com/clojure/clojure/blob/master/changes.md#23-clojurecoreset-agent-send-executor-set-agent-send-off-executor-and-send-via

One remaining issue is the topic of this ticket, which is how best to avoid this 60-second pause.

Approach #1: automatically shut down agents

One method is mentioned in Chas Emerick's original description below, suggested by Rich Hickey, but perhaps long enough ago he may no longer endorse it: Create a Var *auto-shutdown-agents* that when true (the default value), clojure.lang.Agent shutdown() is called after the clojure.main entry point. This removes the surprising wait for common methods of starting Clojure, while allowing expert users to change that value to false if desired.

Approach #2: create daemon threads by default

Another method mentioned by several people in the comments is to change the threads created in agent thread pools to daemon threads by default, and perhaps to deprecate shutdown-agents or modify it to be less dangerous. That approach is discussed a bit more in Alex's blog post linked above, and in a comment from Alexander Taggart on July 11, 2011 below.

Approach #3:

The only other comment before 2014 that is not elaborated in this summary is shoover's suggestion: There are already well-defined and intuitive ways to block on agents and futures. Why not deprecate shutdown-agents and force users to call await and deref if they really want to block? In the pmap situation one would have to evaluate the pmap form.

Approach #4: Create a cached thread pool with a timeout much lower than 60 seconds

This could be done by using one of the ThreadPoolExecutor constructors with a keepAliveTime parameter of the desired time.

Patch: clj-124-v1.patch clj-124-daemonthreads-v1.patch

At most one of these patches should be considered, depending upon the desired approach to take.

Patch clj-124-v1.patch implements appproach #1 using *auto-shutdown-agents*. See the Jul 31 2014 comment when this patch was added for some additional details.

Patch clj-124-daemonthreads-v1.patch implements approach #2 and is straightforward.

Reported by cemer...@snowtide.com, Jun 01, 2009

There has been intermittent chatter over the past months from a couple of
people on the group (e.g.
http://groups.google.com/group/clojure/browse_thread/thread/409054e3542adc1f)
and in #clojure about some clojure scripts hanging, either for a constant
time (usually reported as a minute or so with no CPU util) or seemingly
forever (or until someone kills the process).

I just hit a similar situation in our compilation process, which invokes
clojure.lang.Compile from ant.  The build process for this particular
project had taken 15 second or so, but after adding a couple of pmap calls,
that build time jumped to ~1:15, with roughly zero CPU utilization over the
course of that last minute.

Adding a call to Agent.shutdown() in the finally block in
clojure.lang.Compile/main resolved the problem; a patch including this
change is attached.  I wouldn't suspect anyone would have any issues with
such a change.

-----
In general, it doesn't seem like everyone should keep tripping over this
problem in different directions.  It's a very difficult thing to debug if
you're not attuned to how clojure's concurrency primitives work under the
hood, and I would bet that newer users would be particularly affected.

After discussion in #clojure, rhickey suggested adding a
*auto-shutdown-agents* var, which:

- if true when exiting one of the main entry points (clojure.main, or the
legacy script/repl entry points), Agent.shutdown() would be called,
allowing for the clean exit of the application

- would be bound by default to true

- could be easily set to false for anyone with an advanced use-case that
requires agents to remain active after the main thread of the application
exits.

This would obviously not help anyone initializing clojure from a different
entry point, but this may represent the best compromise between
least-surprise and maximal functionality for advanced users.

------

In addition to the above, it perhaps might be worthwhile to change the
keepalive values used to create the Threadpools used by c.l.Actor's
Executors.  Currently, Actor uses a default thread pool executor, which
results in a 60s keepalive.  Lowering this to something much smaller (1s?
5s?) would additionally minimize the impact of Agent's threadpools on Java
applications that embed clojure directly (and would therefore not benefit
from *auto-shutdown-agents* as currently conceived, leading to puzzling
'hanging' behaviour).  I'm not in a position to determine what impact this
would have on performance due to thread churn, but it would at least
minimize what would be perceived as undesirable behaviour by users that are
less familiar with the implementation details of Agent and code that
depends on it.

Comment 1  by cemer...@snowtide.com, Jun 01, 2009

Just FYI, I'd be happy to provide patches for either of the suggestions mentioned
above...


 Comments   
Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

Converted from http://www.assembla.com/spaces/clojure/tickets/124
Attachments:
compile-agent-shutdown.patch - https://www.assembla.com/spaces/clojure/documents/a56S2ow4ur3O2PeJe5afGb/download/a56S2ow4ur3O2PeJe5afGb
124-compilation.diff - https://www.assembla.com/spaces/clojure/documents/aqn0IGxZSr3RUGeJe5aVNr/download/aqn0IGxZSr3RUGeJe5aVNr

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

oranenj said: [file:a56S2ow4ur3O2PeJe5afGb]

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

richhickey said: Updating tickets (#8, #19, #30, #31, #126, #17, #42, #47, #50, #61, #64, #69, #71, #77, #79, #84, #87, #89, #96, #99, #103, #107, #112, #113, #114, #115, #118, #119, #121, #122, #124)

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

cemerick said: (In [[r:fa3d24973fc415b35ae6ec8d84b61ace76bd4133]]) Add a call to Agent.shutdown() at the end of clojure.lang.Compile/main Refs #124

Signed-off-by: Chouser <chouser@n01se.net>

Branch: master

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

chouser@n01se.net said: I'm closing this ticket to because the attached patch solves a specific problem. I agree that the idea of an auto-shutdown-agents var sounds like a positive compromise. If Rich wants a ticket to track that issue, I think it'd be best to open a new ticket (and perhaps mention this one there) rather than use this ticket to track further changes.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

scgilardi said: With both Java 5 and Java 6 on Mac OS X 10.5 Leopard I'm getting an error when compiling with this change present.

Java 1.5.0_19
Java 1.6.0_13

For example, when building clojure using "ant" from within my clone of the clojure repo:

[java] java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThread)
[java] at java.security.AccessControlContext.checkPermission(AccessControlContext.java:264)
[java] at java.security.AccessController.checkPermission(AccessController.java:427)
[java] at java.util.concurrent.ThreadPoolExecutor.shutdown(ThreadPoolExecutor.java:894)
[java] at clojure.lang.Agent.shutdown(Agent.java:34)
[java] at clojure.lang.Compile.main(Compile.java:71)

I reproduced this on two Mac OS X 10.5 machines. I'm not aware of having any enhanced security policies along these lines on my machines. The compile goes fine for me with Java 1.6.0_0 on an Ubuntu box.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

chouser@n01se.net said: I had only tested it on my ubuntu box – looks like that was openjdk 1.6.0_0. I'll test again with sun-java5 and sun-java6.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

chouser@n01se.net said: 1.6.0_13 worked fine for me on ubuntu, but 1.5.0_18 generated an the exception Steve pasted. Any suggestions? Should this patch be backed out until someone has a fix?

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

achimpassen said: [file:aqn0IGxZSr3RUGeJe5aVNr]

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

chouser@n01se.net said: With Achim's patch, clojure compiles for me on ubuntu using java 1.5.0_18 from sun, and still works on 1.6.0_13 sun and 1.6.0_0 openjdk. I don't know anything about ant or the security error, but this is looking good to me.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

achimpassen said: It works for me on 1.6.0_13 and 1.5.0_19 (32 and 64 bit) on OS X 10.5.7.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

chouser@n01se.net said: (In [[r:895b39dabc17b3fd766fdbac3b0757edb0d4b60d]]) Rev fa3d2497 causes compile to fail on some VMs – back it out. Refs #124

Branch: master

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

mikehinchey said: I got the same compile error on both 1.5.0_11 and 1.6.0_14 on Windows. Achim's patch fixes both.

See the note for "permissions" on http://ant.apache.org/manual/CoreTasks/java.html . I assume ThreadPoolExecutor.shutdown is the problem, it would shutdown the main Ant thread, so Ant disallows that. Forking avoids the permissions limitation.

In addition, since the build error still resulted in "BUILD SUCCESSFUL", I think failonerror="true" should also be added to the java call so the build would totally fail for such an error.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

chouser@n01se.net said: I don't know if the <java fork=true> patch is a good idea or not, or if there's a better way to solve the original problem.

Chas, I'm kicking back to you, but I guess if you don't want it you can reassign to "nobody".

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

richhickey said: Updating tickets (#8, #42, #113, #2, #20, #94, #96, #104, #119, #124, #127, #149, #162)

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

shoover said: I'd like to suggest an alternate approach. There are already well-defined and intuitive ways to block on agents and futures. Why not deprecate shutdown-agents and force users to call await and deref if they really want to block? In the pmap situation one would have to evaluate the pmap form.

The System.exit problem goes away if you configure the threadpools to use daemon threads (call new ThreadPoolExecutor and pass a thread factory that creates threads and sets daemon to true). That way the user has an explicit means of blocking and System.exit won't hang.

Comment by Assembla Importer [ 24/Aug/10 12:45 AM ]

alexdmiller said: I blogged about these issues at:
http://tech.puredanger.com/2010/06/08/clojure-agent-thread-pools/

I think that:

  • agent thread pool threads should be named (see ticket #378)
  • agent thread pools must be daemon threads by default
  • having ways to specify an customized executor pool for an agent send/send-off is essential to customize threading behavior
  • (shutdown-agents) should be either deprecated or made less dangerous
Comment by Alexander Taggart [ 11/Jul/11 9:33 PM ]

Rich, what is the intention behind using non-daemon threads in the agent pools?

If it is because daemon threads could terminate before their work is complete, would it be acceptable to add a shutdown hook to ensure against such premature termination? Such a shutdown hook could call Agent.shutdown(), then awaitTermination() on the pools.

Comment by Christopher Redinger [ 27/Nov/12 3:47 PM ]

Moving this ticket out of approval "OK" status, and dropping the priority. These were Assembla import defaults.

Also, Chas gets to be the Reporter now.

Comment by Chas Emerick [ 27/Nov/12 5:56 PM ]

Heh, blast from the past.

The comment import appears to have set their timestamps to the date of the import, so the conversation is pretty hard to follow, and obviously doesn't benefit from the intervening years of experience. In addition, there have been plenty of changes to agents, including some recent enhancements that address some of the pain points that Alex Miller mentioned above.

I propose closing this as 'invalid' or whatever, and opening one or more new issues to track whatever issues still persist (presumably based on fresh ML discussion, etc).

Comment by Andy Fingerhut [ 27/Nov/12 6:11 PM ]

Rereading the original description of this ticket, without reading all of the comments that follow, that description is still right on target for the behavior of latest Clojure master today.

People send messages to the Clojure Google group every couple of months hitting this issue, and one even filed CLJ-959 because of hitting it. I have updated the examples on ClojureDocs.org for future, and also for pmap and clojure.java.shell/sh which use future in their implementations, to warn people about this and explain that they should call (shutdown-agents), but making it unnecessary to call shutdown-agents would be even better, at least as the default behavior. It sounds fine to me to provide a way for experts on thread behavior to change that default behavior if they need to.

Comment by Andy Fingerhut [ 31/Jul/14 6:39 PM ]

Patch clj-124-v1.patch dated Jul 31 2014 implements the approach of calling clojure.lang.Agent#shutdown when the new Var *auto-shutdown-agents* is true, which is its default value.

I don't see any benefit to making this Var dynamic. Unless I am missing something, only the root binding value is visible after clojure.main/main returns, not any binding that would be pushed on top of that if it were dynamic. It seems to require alter-var-root to change it to false in a way that this patch would avoid calling clojure.lang.Agent#shutdown.

This patch only adds the shutdown call to clojure.main#main, but can easily be added to the legacy_repl and legacy_script methods if desired.

Comment by Andy Fingerhut [ 23/Aug/14 11:49 AM ]

Patch clj-124-daemonthreads-v1.patch dated Aug 23 2014 simply modifies the ThreadFactory so that every thread created in an agent thread pool is a daemon thread.





[CLJ-1148] adds docstring support to defonce Created: 17/Jan/13  Updated: 09/Jan/18

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: Joe Gallo Assignee: Unassigned
Resolution: Unresolved Votes: 12
Labels: docstring

Attachments: Text File 0001-new-defonce-hotness.patch     Text File clj-1148-defonce-2.patch     Text File clj-1148-defonce-3.patch     Text File clj-1148-defonce-4.patch     Text File clj-1148-defonce-4.patch     Text File clj-1148-defonce-5.patch     Text File clj-1148-defonce-6.patch     Text File defonce_fixes.patch    
Patch: Code and Test
Approval: Vetted

 Description   

Pass all args from defonce on to def so it supports docstrings (or potentially other future features) just like def.

Docstrings and other Var metadata will be lost when the defonce is reëvaluated.

Patch: clj-1148-defonce-6.patch

Screened by:



 Comments   
Comment by Alex Miller [ 29/Aug/13 9:53 AM ]

Changed to defect for stomping metadata.

Comment by Stuart Halloway [ 18/Oct/13 8:00 AM ]

Please add tests. The clojure.test-helper namespace has useful temporary namespace support.

Comment by Joe Gallo [ 24/Oct/13 12:44 PM ]

This new patch includes the changes to defonce and also tests.

Comment by Alex Miller [ 24/Oct/13 2:14 PM ]

Changing to Vetted so this is screenable again.

Comment by Rich Hickey [ 22/Nov/13 11:31 AM ]

I disagree about the stomp metadata - different metadata was provided. The purpose of defonce is to avoid the re-evaluation of the init. Is this the simplest change that accomplishes the doc string? In any case split in two.

Comment by Alex Miller [ 29/Dec/13 10:24 PM ]

Reduced scope of ticket to just passing defonce args on to def to add support for docstring. Added new patch that does this.

Comment by Stuart Sierra [ 10/Jan/14 4:09 PM ]

Screened clj-1148-defonce-2.patch but returning to 'incomplete' status.

The :arglists metadata in this patch (a list of symbols) is inconsistent with all other uses of :arglists (a list of vectors).

Other than that the patch is good.

Comment by Alex Miller [ 10/Jan/14 5:04 PM ]

Updated patch to address inconsistency in arglist format and attached clj-1148-defonce-3.patch.

Comment by Stuart Sierra [ 17/Jan/14 9:36 AM ]

The patch clj-1148-defonce-3.patch is OK but it doesn't really address the docstring issue because defonce still destroys metadata. For example:

user=> (defonce foo "docstring for foo" (do (prn 42) 42))
42
#'user/foo
user=> (doc foo)
-------------------------
user/foo
  docstring for foo
nil
user=> (defonce foo "docstring for foo" (do (prn 42) 42))
nil
user=> (doc foo)
-------------------------
user/foo
  nil
Comment by Stuart Sierra [ 17/Jan/14 10:03 AM ]

Screened with reservations noted.

Comment by Rich Hickey [ 24/Jan/14 10:15 AM ]

Stuart is right, second defonce should retain the doc string (since it again provides it, should be no-op)

Comment by Alex Miller [ 20/Feb/14 10:41 AM ]

pull out of 1.6

Comment by Linus Ericsson [ 28/Aug/14 12:30 PM ]

This version looks for previously defined var with resolve. A repeated defonce won't affect the namespace at all if the variable is already defined and bounded.

Please confirm using (resolve '~name) is not a problem w.r.t ns-bindings or similar.

This patch also contains the tests from clj-1148-defonce-3.patch as well as the :arglists property.

(patch 4 missed one def-row, sorry for mailbox noise).

Comment by Linus Ericsson [ 09/Sep/14 4:27 AM ]

Yet another, simpler version of defonce. No test-cases included.

This version just makes an (or (nil? v#) (not (.hasRoot v#)) test on the resolved variable. If this is true, really define by (def ~name ~@args) else do nothing.

Comment by Andy Fingerhut [ 08/Jan/15 6:04 PM ]

Linus, while JIRA can handle multiple attachments on the same ticket with identical names, it can be confusing to do so. Would you mind renaming or removing the ones you have added with duplicate names, e.g. delete obsolete ones, perhaps? Instructions for deleting patches are in the "Removing patches" section on this wiki page: http://dev.clojure.org/display/community/Developing+Patches

Comment by Sean Corfield [ 09/Jan/18 7:30 PM ]

On noticing that we have a JIRA issue at work to add docstrings to the handful of defonce calls we have (via alter-meta!), I came upon this issue and wondered what is stopping it moving forward?

Is Linus's patch an acceptable solution overall (and is just missing tests)? Or is a different approach wanted? Is this blocked by CLJ-1446 and folks want that fixed before updating defonce?





[CLJ-1814] Make `satisfies?` as fast as a protocol method call Created: 11/Sep/15  Updated: 18/Sep/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Critical
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 11
Labels: performance, protocols

Attachments: Text File 0001-CLJ-1814-cache-protocol-impl-satisfies-as-fast-as-me.patch     Text File 0001-CLJ-1814-cache-protocol-impl-satisfies-as-fast-as-me-v2.patch     Text File 0001-CLJ-1814-cache-protocol-impl-satisfies-as-fast-as-me-v3.patch     Text File 0001-CLJ-1814-cache-protocol-impl-satisfies-as-fast-as-me-v4.patch     Text File 0001-CLJ-1814-cache-protocol-impl-satisfies-as-fast-as-me-v5.patch     Text File CLJ-1814-v6.patch    
Patch: Code and Test
Approval: Vetted

 Description   

Currently `satisfies?` doesn't use the same impl cache used by protocol methods, making it too slow for real world usage.

With:

(defprotocol p (f [_]))
(deftype x [])
(deftype y [])
(extend-type x p (f [_]))

Before patch:

(let [s "abc"] (bench (instance? CharSequence s))) ;; Execution time mean : 1.358360 ns
(let [x (x.)] (bench (satisfies? p x))) ;; Execution time mean : 112.649568 ns
(let [y (y.)] (bench (satisfies? p y))) ;; Execution time mean : 2.605426 µs

Cause: `satisfies?` calls `find-protocol-impl` to see whether an object implements a protocol, which checks for whether x is an instance of the protocol interface or whether x's class is one of the protocol implementations (or if its in an inheritance chain that would make this true). This check is fairly expensive and not cached.

Proposed: Extend the protocol's method impl cache to also handle (and cache) instance checks (including negative results).

After patch:

(let [x (x.)] (bench (satisfies? p x))) ;; Execution time mean : 79.321426 ns
(let [y (y.)] (bench (satisfies? p y))) ;; Execution time mean : 77.410858 ns

Patch: CLJ-1814-v6.patch



 Comments   
Comment by Michael Blume [ 11/Sep/15 4:17 PM ]

Nice. Honeysql used to spend 80-90% of its time in satisfies? calls before we refactored them out.

Comment by Michael Blume [ 24/Sep/15 3:55 PM ]

I realize this is a deeply annoying bug to reproduce, but if I clone core.match, point its Clojure dependency to 1.8.0-master-SNAPSHOT, start a REPL, connect to the REPL from vim, and reload clojure.core.match, I get

|| java.lang.Exception: namespace 'clojure.tools.analyzer.jvm.utils' not found, compiling:(clojure/tools/analyzer/jvm.clj:9:1)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5647| clojure.core$throw_if.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5733| clojure.core$load_lib.invokeStatic
|| clojure.core$load_lib.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:142)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5765| clojure.core$load_libs.invokeStatic
|| clojure.core$load_libs.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:137)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5787| clojure.core$require.invokeStatic
|| clojure.core$require.doInvoke(core.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:703)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.analyzer.jvm/0.6.5/tools.analyzer.jvm-0.6.5.jar::clojure/tools/analyzer/jvm.clj|9| clojure.tools.analyzer.jvm$eval4968$loading__5561__auto____4969.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.analyzer.jvm/0.6.5/tools.analyzer.jvm-0.6.5.jar::clojure/tools/analyzer/jvm.clj|9| clojure.tools.analyzer.jvm$eval4968.invokeStatic
|| clojure.tools.analyzer.jvm$eval4968.invoke(jvm.clj)
|| clojure.lang.Compiler.eval(Compiler.java:6934)
|| clojure.lang.Compiler.eval(Compiler.java:6923)
|| clojure.lang.Compiler.load(Compiler.java:7381)
|| clojure.lang.RT.loadResourceScript(RT.java:372)
|| clojure.lang.RT.loadResourceScript(RT.java:363)
|| clojure.lang.RT.load(RT.java:453)
|| clojure.lang.RT.load(RT.java:419)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5883| clojure.core$load$fn__5669.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5882| clojure.core$load.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5683| clojure.core$load_one.invokeStatic
|| clojure.core$load_one.invoke(core.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5728| clojure.core$load_lib$fn__5618.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5727| clojure.core$load_lib.invokeStatic
|| clojure.core$load_lib.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:142)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5765| clojure.core$load_libs.invokeStatic
|| clojure.core$load_libs.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:137)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5787| clojure.core$require.invokeStatic
|| clojure.core$require.doInvoke(core.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:457)
src/main/clojure/clojure/core/match.clj|1| clojure.core.match$eval4960$loading__5561__auto____4961.invoke
src/main/clojure/clojure/core/match.clj|1| clojure.core.match$eval4960.invokeStatic
|| clojure.core.match$eval4960.invoke(match.clj)
|| clojure.lang.Compiler.eval(Compiler.java:6934)
|| clojure.lang.Compiler.eval(Compiler.java:6923)
|| clojure.lang.Compiler.load(Compiler.java:7381)
|| clojure.lang.RT.loadResourceScript(RT.java:372)
|| clojure.lang.RT.loadResourceScript(RT.java:363)
|| clojure.lang.RT.load(RT.java:453)
|| clojure.lang.RT.load(RT.java:419)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5883| clojure.core$load$fn__5669.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5882| clojure.core$load.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5683| clojure.core$load_one.invokeStatic
|| clojure.core$load_one.invoke(core.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5728| clojure.core$load_lib$fn__5618.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5727| clojure.core$load_lib.invokeStatic
|| clojure.core$load_lib.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:142)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5765| clojure.core$load_libs.invokeStatic
|| clojure.core$load_libs.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:137)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5787| clojure.core$require.invokeStatic
|| clojure.core$require.doInvoke(core.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:421)
|| clojure.core.match$eval4949.invokeStatic(form-init2494799382238714928.clj:1)
|| clojure.core.match$eval4949.invoke(form-init2494799382238714928.clj)
|| clojure.lang.Compiler.eval(Compiler.java:6934)
|| clojure.lang.Compiler.eval(Compiler.java:6897)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|3096| clojure.core$eval.invokeStatic
|| clojure.core$eval.invoke(core.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|240| clojure.main$repl$read_eval_print__7404$fn__7407.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|240| clojure.main$repl$read_eval_print__7404.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|258| clojure.main$repl$fn__7413.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|258| clojure.main$repl.invokeStatic
|| clojure.main$repl.doInvoke(main.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:1523)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|58| clojure.tools.nrepl.middleware.interruptible_eval$evaluate$fn__637.invoke
|| clojure.lang.AFn.applyToHelper(AFn.java:152)
|| clojure.lang.AFn.applyTo(AFn.java:144)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|645| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|1874| clojure.core$with_bindings_STAR_.invokeStatic
|| clojure.core$with_bindings_STAR_.doInvoke(core.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:425)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|56| clojure.tools.nrepl.middleware.interruptible_eval$evaluate.invokeStatic
|| clojure.tools.nrepl.middleware.interruptible_eval$evaluate.invoke(interruptible_eval.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|191| clojure.tools.nrepl.middleware.interruptible_eval$interruptible_eval$fn__679$fn__682.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|159| clojure.tools.nrepl.middleware.interruptible_eval$run_next$fn__674.invoke
|| clojure.lang.AFn.run(AFn.java:22)
|| java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
|| java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
|| java.lang.Thread.run(Thread.java:745)

Same thing with reloading a namespace in my own project which depends on clojure.core.match

Comment by Nicola Mometto [ 24/Sep/15 3:59 PM ]

is it possible that AOT is involved?

Comment by Michael Blume [ 24/Sep/15 5:31 PM ]

Narrowed it down a little, if I check out tools.analyzer.jvm, open a REPL, and do (require 'clojure.tools.analyzer.jvm.utils) I get

|| java.lang.ClassCastException: java.lang.Class cannot be cast to clojure.asm.Type, compiling:(utils.clj:260:13)
|| clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3642)
|| clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3636)
|| clojure.lang.Compiler$DefExpr.eval(Compiler.java:450)
|| clojure.lang.Compiler.eval(Compiler.java:6939)
|| clojure.lang.Compiler.load(Compiler.java:7381)
|| clojure.lang.RT.loadResourceScript(RT.java:372)
|| clojure.lang.RT.loadResourceScript(RT.java:363)
|| clojure.lang.RT.load(RT.java:453)
|| clojure.lang.RT.load(RT.java:419)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5883| clojure.core$load$fn__5669.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5882| clojure.core$load.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5683| clojure.core$load_one.invokeStatic
|| clojure.core$load_one.invoke(core.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5728| clojure.core$load_lib$fn__5618.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5727| clojure.core$load_lib.invokeStatic
|| clojure.core$load_lib.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:142)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5765| clojure.core$load_libs.invokeStatic
|| clojure.core$load_libs.doInvoke(core.clj)
|| clojure.lang.RestFn.applyTo(RestFn.java:137)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|647| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|5787| clojure.core$require.invokeStatic
|| clojure.core$require.doInvoke(core.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:421)
|| clojure.tools.analyzer.jvm.utils$eval4392.invokeStatic(form-init8663423518975891793.clj:1)
|| clojure.tools.analyzer.jvm.utils$eval4392.invoke(form-init8663423518975891793.clj)
|| clojure.lang.Compiler.eval(Compiler.java:6934)
|| clojure.lang.Compiler.eval(Compiler.java:6897)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|3096| clojure.core$eval.invokeStatic
|| clojure.core$eval.invoke(core.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|240| clojure.main$repl$read_eval_print__7404$fn__7407.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|240| clojure.main$repl$read_eval_print__7404.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|258| clojure.main$repl$fn__7413.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/main.clj|258| clojure.main$repl.invokeStatic
|| clojure.main$repl.doInvoke(main.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:1523)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|58| clojure.tools.nrepl.middleware.interruptible_eval$evaluate$fn__637.invoke
|| clojure.lang.AFn.applyToHelper(AFn.java:152)
|| clojure.lang.AFn.applyTo(AFn.java:144)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|645| clojure.core$apply.invokeStatic
zipfile:/Users/michael.blume/.m2/repository/org/clojure/clojure/1.8.0-master-SNAPSHOT/clojure-1.8.0-master-SNAPSHOT.jar::clojure/core.clj|1874| clojure.core$with_bindings_STAR_.invokeStatic
|| clojure.core$with_bindings_STAR_.doInvoke(core.clj)
|| clojure.lang.RestFn.invoke(RestFn.java:425)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|56| clojure.tools.nrepl.middleware.interruptible_eval$evaluate.invokeStatic
|| clojure.tools.nrepl.middleware.interruptible_eval$evaluate.invoke(interruptible_eval.clj)
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|191| clojure.tools.nrepl.middleware.interruptible_eval$interruptible_eval$fn__679$fn__682.invoke
zipfile:/Users/michael.blume/.m2/repository/org/clojure/tools.nrepl/0.2.10/tools.nrepl-0.2.10.jar::clojure/tools/nrepl/middleware/interruptible_eval.clj|159| clojure.tools.nrepl.middleware.interruptible_eval$run_next$fn__674.invoke
|| clojure.lang.AFn.run(AFn.java:22)
|| java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
|| java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
|| java.lang.Thread.run(Thread.java:745)

I don't see where AOT would be involved?

Comment by Nicola Mometto [ 27/Sep/15 2:28 PM ]

Michael Blume The updated patch should fix the issue you reported

Comment by Michael Blume [ 28/Sep/15 12:39 PM ]

Cool, thanks =)

New patch no longer deletes MethodImplCache, which is not used – is that deliberate?

Comment by Alex Miller [ 02/Nov/15 3:08 PM ]

It would be cool if there was a bulleted list of the things changed in the patch in the description. For example: "Renamed MethodImplCache to ImplCache", etc. That helps makes it easier to review.

Comment by Nicola Mometto [ 02/Nov/15 3:35 PM ]

Attached is an updated patch that doesn't replace MethodImplCache with ImplCache but simply reuses MethodImplCache, reducing the impact of this patch and making it easier (and safer) to review.

Comment by Alex Miller [ 07/Jun/16 11:42 AM ]

Bumping priority as this is used in new inst? predicate - see https://github.com/clojure/clojure/commit/58227c5de080110cb2ce5bc9f987d995a911b13e

Comment by Alex Miller [ 29/Jun/17 2:31 PM ]

I ran the before and after tests with the v3 patch. Before times matched pretty closely but I could not replicate the after results. I got this which is actually much worse in the not found case:

(let [x (x.)] (bench (satisfies? p x))) ;; Execution time mean : 76.833504 ns
(let [y (y.)] (bench (satisfies? p y))) ;; Execution time mean : 20.570007 µs
Comment by Nicola Mometto [ 29/Jun/17 4:09 PM ]

v4 patch fixes the regression on the not-found case, not sure how that happened, apologies.
Here are the timings I'm getting now:

clojure master:

user=> (let [x (x.)] (bench (satisfies? p x)))
Evaluation count : 604961580 in 60 samples of 10082693 calls.
             Execution time mean : 112.649568 ns
    Execution time std-deviation : 12.216782 ns
   Execution time lower quantile : 99.299203 ns ( 2.5%)
   Execution time upper quantile : 144.265205 ns (97.5%)
                   Overhead used : 1.898271 ns

Found 3 outliers in 60 samples (5.0000 %)
	low-severe	 2 (3.3333 %)
	low-mild	 1 (1.6667 %)
 Variance from outliers : 73.7545 % Variance is severely inflated by outliers
nil
user=> (let [y (y.)] (bench (satisfies? p y)))
Evaluation count : 22676100 in 60 samples of 377935 calls.
             Execution time mean : 2.605426 µs
    Execution time std-deviation : 141.100070 ns
   Execution time lower quantile : 2.487234 µs ( 2.5%)
   Execution time upper quantile : 2.873045 µs (97.5%)
                   Overhead used : 1.898271 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 40.1251 % Variance is moderately inflated by outliers
nil

master + v4:

user=> (let [x (x.)] (bench (satisfies? p x)))
Evaluation count : 731759100 in 60 samples of 12195985 calls.
             Execution time mean : 79.321426 ns
    Execution time std-deviation : 3.959245 ns
   Execution time lower quantile : 75.365187 ns ( 2.5%)
   Execution time upper quantile : 87.986479 ns (97.5%)
                   Overhead used : 1.905711 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 35.2614 % Variance is moderately inflated by outliers
nil
user=> (let [y (y.)] (bench (satisfies? p y)))
Evaluation count : 771220140 in 60 samples of 12853669 calls.
             Execution time mean : 77.410858 ns
    Execution time std-deviation : 1.407926 ns
   Execution time lower quantile : 75.852530 ns ( 2.5%)
   Execution time upper quantile : 80.759226 ns (97.5%)
                   Overhead used : 1.897646 ns

Found 4 outliers in 60 samples (6.6667 %)
	low-severe	 3 (5.0000 %)
	low-mild	 1 (1.6667 %)
 Variance from outliers : 7.7866 % Variance is slightly inflated by outliers

So to summarize:
master found = 112ns
master not-found = 2.6us

master+v4 found = 79ns
master+v4 not-found = 77ns

Comment by Michael Blume [ 14/Jul/17 5:12 PM ]

For records that have been declared with an implementation of a particular protocol, and which therefore implement the corresponding interface, would it make sense to use an (instance?) check against that interface as a fast path?

Comment by Alex Miller [ 04/Aug/17 11:28 AM ]

Michael - that check is already in there

Nicola - I have a few comments/questions:

1. I don't get what the purpose of the NIL stuff is - could you explain that?
2. In the case where x is an instance of the interface, the old code returned x and the new code in find-protocol-impl* returns interface. Why the change?
3. This: (alter-var-root (:var protocol) assoc :impl-cache (expand-method-impl-cache cache c impl)) is not thread-safe afaict - I think simultaneous misses in two different threads for different impls would cause the cache to only have one of them. This is probably unlikely, and probably not a big deal since the cache will just be updated on the next call (not give a wrong answer), but wanted to mention it. I don't see any easy way to avoid it without a lot of changes.

Comment by Nicola Mometto [ 04/Aug/17 6:14 PM ]

Alex, thanks for looking at this,
1- The NIL object is a placeholder in the method impl cache for nil, as `find-and-cache-protocol-impl` tests for `nil?` to know if the dispatch has been cached or not

2- The change is purely a consistency one, making find-and-cache-protocol-impl always return a class/interface rather than either a class/interface or a concrete instance. Behaviourally, it doesn't change anything since the two consumers of `find-protocol-impl`, namely `find-protocol-method` and `satisfies?` don't care what that value is in that case

3- Yes you are correct that it is not thread safe, however I think it's a decent tradeoff as it doesn't cause any incorrect behaviour and at worse would cause an extra cache miss, making it thread safe would mean an extra performance penalty in every cache hit/miss

Comment by Michael Blume [ 16/Aug/17 1:44 PM ]

Nicola Mometto I'm seeing a change in behavior from this patch

(defprotocol BoolProtocol
  (proto-fn [this]))

(extend-protocol BoolProtocol
  Object
  (proto-fn [x] "Object impl")

  nil
  (proto-fn [x] "Nil impl"))

(proto-fn false)

returns "Object impl" with Clojure master and "Nil impl" with this patch

Comment by Nicola Mometto [ 17/Aug/17 3:08 AM ]

That's not good, I'll take a look later today, thanks

Comment by Nicola Mometto [ 18/Aug/17 3:29 AM ]

This was an issue with how `nil` was cached, I decided to special-case `nil` to skip the method cache, removing the need for all the `NIL` funny business and fixing this bad interaction between `false` and `nil`.

Comment by Michael Blume [ 18/Aug/17 1:17 PM ]

Not sure if it's in scope for this ticket, but given that this wasn't caught, there should probably be more protocol dispatch tests

Comment by Alex Miller [ 20/Aug/17 5:00 PM ]

yes, should definitely add

Comment by Michael Blume [ 21/Aug/17 12:52 PM ]

Patch with test

Comment by Michael Blume [ 21/Aug/17 12:56 PM ]

Verified that test fails with v4 patch:

[java] Testing clojure.test-clojure.protocols
     [java]
     [java] FAIL in (test-default-dispatch) (protocols.clj:695)
     [java] expected: (= "Object impl" (test-dispatch false))
     [java]   actual: (not (= "Object impl" "Nil impl"))
     [java]
     [java] FAIL in (test-default-dispatch) (protocols.clj:695)
     [java] expected: (= "Object impl" (test-dispatch true))
     [java]   actual: (not (= "Object impl" "Nil impl"))
Comment by Michael Blume [ 18/Sep/17 2:19 PM ]

Has this patch missed the 1.9 train? There was a fix we were hoping to make in HoneySQL that I'd hesitate to make with satisfies? as slow as it is.

Comment by Alex Miller [ 18/Sep/17 2:48 PM ]

Not necessarily. We don't add features after 1.9 but perf stuff like this is still possible. It's been vetted by Rich. It's in my list of stuff to screen.





[CLJ-1611] clojure.java.io/pushback-reader Created: 08/Dec/14  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Feature Priority: Critical
Reporter: Phill Wolf Assignee: Unassigned
Resolution: Unresolved Votes: 11
Labels: io, reader

Attachments: Text File drupp-clj-1611-2.patch     Text File drupp-clj-1611.patch    
Approval: Triaged

 Description   

Whereas

  • clojure.core/read and clojure.edn/read require a PushbackReader;
  • clojure.java.io/reader produces a BufferedReader, which isn't compatible;
  • the hazard has tripped folks up for years[1];
  • clojure.java.io is pure sugar anyway (and would not be damaged by the addition of a little bit more);
  • clojure.java.io's very existence suggests suitability and fitness for use (wherein by the absence of a read-compatible pushback-reader it falls short);

i.e., in the total absence of clojure.java.io it would not seem "hard" to use clojure.edn, but in the presence of clojure.java.io and its "reader" function, amidst so much else in the API that does fit together, one keeps thinking one is doing it wrong;

and

  • revising the "read" functions to make their own Pushback was considered but rejected [2];

Therefore let it be suggested to add clojure.java.io/pushback-reader, returning something consumable by clojure.core/read and clojure.edn/read.

[1] The matter was discussed on Google Groups:

(2014, "clojure.edn won't accept clojure.java.io/reader?") https://groups.google.com/forum/#!topic/clojure/3HSoA12v5nc

with a reference to an earlier thread

(2009, "Reading... from a reader") https://groups.google.com/forum/#!topic/clojure/_tuypjr2M_A

[2] CLJ-82 and the 2009 message thread



 Comments   
Comment by David Rupp [ 10/Jan/15 4:05 PM ]

Attached patch drupp-clj-1611.patch implements clojure.java.io/pushback-reader as requested.

Comment by David Rupp [ 10/Jan/15 4:07 PM ]

Note that you can always import java.io.PushbackReader and do something like (PushbackReader. (reader my-thing)) yourself; that's really all the patch does.

Comment by Phill Wolf [ 11/Jan/15 7:54 AM ]

clojure.java.io/reader is idempotent, while the patch of 10-Jan-2015 re-wraps an existing PushbackReader twice: first with a new BufferedReader, then with a new PushbackReader.

Leaving a given PushbackReader alone would be more in keeping with the pattern of clojure.java.io.

It also needs a docstring. If pushback-reader were idempotent, the docstring's opening phrase could echo clojure.java.io/reader's, e.g.: Attempts to coerce its argument to java.io.PushbackReader; failing that, (bla bla bla).

Comment by David Rupp [ 11/Jan/15 11:14 AM ]

Adding drupp-clj-1611-2.patch to address previous comments.





[CLJ-2194] Spec metadata support Created: 30/Jun/17  Updated: 07/Jul/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Max Penet Assignee: Unassigned
Resolution: Unresolved Votes: 11
Labels: spec


 Description   
  1. Spec metadata support

Problem: Currently there is no way to attach metadata to a spec

It would be nice to be able to add a docstring (the primary use case),
or potentially useful information about usage of that spec in different
contexts (static code analyser, custom conversion/coercion, how it
relates to a particular db schema, human readable error message
template, domain specific concerns or even clj.spec itself later, etc...).

In theory one can today create his own meta-data registry and handle
this at the library level, and that's what a few spec related project
already do, but it would be nicer to have a unified/standard way to do
this. By default it would make sense to add support docstrings for a
start. It could take the form of an extra argument of:

;; at least the following two
(s/def ::foo "Something that's a foo" any?)
(s/def ::foo string? {:doc "Something that's a foo" :cassandra-type :varchar})

;; potentially these depending on the implementation
(s/spec #() :gen ... :meta ...)
(with-meta (s/spec ...))

There are a few ways to implement this, with various pros/cons:

  • Implement the IMeta protocol:
    This seems like the clean approach, meta data would/could be supported
    at any Spec level (ex a non registered spec predicate, a Set spec and
    so on). The implementation would require a fair amount changes to the
    current code tho. Mostly adding a meta parameter to the various
    *-spec-impl macros and sugar at `s/def` and derivatives' level.
    A tricky part with that approach is that registered specs that reference
    another spec are just a "link" (a keyword), so we have nowhere to add
    metadata right now.
    They could be reified, return a "pointer" to their original spec and hold
    metadata at their own level.
  • a simple registry (similar to the spec registry, or shared in the main spec registry):
    Basically a map of spec-kw -> metadata if in a separate registry, or integrated into the
    main registry somehow.
    That's the easy approach, only registered spec would be supported, metadata is separated
    from the rest, would keep the Spec instances a bit lighter. Spec referencing other specs
    could have their own metadata.
    As mentioned this could be done in a separate registry or added to a spec value in the main spec
    registry.

It seems to be the IMeta is probably the better solution, we'd leverage the existing "meta" api.



 Comments   
Comment by Nicola Mometto [ 30/Jun/17 4:20 AM ]

(s/def ^{:doc "Something that's a foo" :cassandra-type :varchar} ::foo string?)
is not valid clojure, you can't add metadata to a keyword

Comment by Max Penet [ 30/Jun/17 4:26 AM ]

Changed example as per Nicolas' comment.

Comment by Andy Fingerhut [ 04/Jul/17 10:44 AM ]

Related to (if not a dup of) CLJ-1965

Comment by Alex Miller [ 04/Jul/17 11:40 AM ]

This is related to but not the same as CLJ-1965 - the scope here is larger to potentially support any meta.





[CLJ-1771] Support for multiple key(s)-value pairs in assoc-in Created: 29/Jun/15  Updated: 15/May/17

Status: Reopened
Project: Clojure
Component/s: None
Affects Version/s: Release 1.7
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Griffin Smith Assignee: Unassigned
Resolution: Unresolved Votes: 11
Labels: None
Environment:

All


Attachments: Text File clj-1771.patch    
Approval: Prescreened

 Description   

It would be nice if assoc-in supported multiple key(s)-to-value pairs (and threw an error when there were an even number of arguments, just like assoc):

user=> (assoc-in {} [:a :b] 1 [:c :d] 2)
{:a {:b 1}, :c {:d 2}}
user=> (assoc-in {} [:a :b] 1 [:c :d])
IllegalArgumentException assoc-in expects even number of arguments after map/vector, found odd number

Patch: clj-1771.patch

Prescreened by: Alex Miller



 Comments   
Comment by Matthew Gilliard [ 23/Jul/15 2:15 PM ]

Simple patch attached. I did not find any existing tests for assoc-in but I could add them if wanted.

Comment by Yehonathan Sharvit [ 19/Aug/16 10:19 AM ]

for the sake of symmetry with `assoc` I'd love to see this ticket fixed

Comment by Alex Miller [ 27/Nov/16 10:33 PM ]

Do you need the "if kvs" check?

Should have tests.

Comment by Matthew Gilliard [ 14/Jan/17 11:34 AM ]

Sorry for the delay - I don't get notifications from this JIRA for some reason.

The patch now includes tests.

Both `if` checks are necessary as we have 3 possible outcomes there:
1/ No more kvs (we are finished)
2/ More kvs (we need to recur)
3/ A sequence of keys but no value (throw IAE)





[CLJ-1610] Unrolled small maps Created: 08/Dec/14  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Alex Miller Assignee: Zach Tellman
Resolution: Unresolved Votes: 11
Labels: collections


 Description   

Placeholder for unrolled small maps enhancement (companion for vectors at CLJ-1517).



 Comments   
Comment by Andy Fingerhut [ 09/Jul/15 10:59 PM ]

Is there an expectation that these would perform better that PersistentArrayMap?

Comment by Zach Tellman [ 09/Jul/15 11:53 PM ]

Yes, in some cases significantly so, for three reasons (in rough order of importance):

  • positional constructors, without any need for array instantiation/population
  • short-circuiting equality checks using hash comparisons
  • no iteration on any operation

There are a series of benchmarks at https://github.com/ztellman/cambrian-collections/blob/master/test/cambrian_collections/map_test.clj#L64-L148, which compare operations against maps with both keywords (which don't benefit from the hash comparisons) and symbols (which do). The 7-entry map cases cause the unrolled maps to overflow, so they only exist to test the overflow mechanism.

I've run the benchmark suite on my laptop, and the results are at https://gist.github.com/ztellman/961001e1a77e4f76ee1d. Some notable results:

The rest of the benchmarks are marginally faster due to unrolling, but most of the performance benefits are from the above behaviors. In a less synthetic benchmark, I found that Cheshire JSON decoding (which is 33% JSON lexing and 66% data structure building) was sped up roughly 30-40%.





[CLJ-1553] Parallel transduce Created: 07/Oct/14  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.7
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 11
Labels: transducers


 Description   

Consider how to create a parallel path for transducers, similar to reducers fold.






[CLJ-1305] Add optional not-found argument when invoking vectors or sets as functions Created: 12/Dec/13  Updated: 13/Dec/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Dave Tenny Assignee: Unassigned
Resolution: Unresolved Votes: 11
Labels: None

Attachments: Text File 0001-Added-tests-for-using-get-on-sets-refs-1305.patch     Text File 0001-add-not-found-to-sets-and-vecs-as-functions-refs-130.patch    
Approval: Triaged

 Description   

Maps, keywords, and symbols when used as operators allow optional second arguments for 'default-not-found' values is if to 'get'.

({:a 1} :b 'b) => b

However sets don't support this behavior (though they do with 'get') and vectors don't allow the optional default-not-found in their pseudo 'nth' semantics.

user=> (#{:a  :b} :b 'notfound)
ArityException Wrong number of args (2) passed to: PersistentHashSet  clojure.lang.AFn.throwArity (AFn.java:437)


 Comments   
Comment by Pepijn de Vos [ 12/Nov/14 1:31 PM ]

I fixed the problem with Dirk at the Amsterdam Clojurians Hackathon.

Comment by Bozhidar Batsov [ 12/Nov/14 3:15 PM ]

Guess you can add a couple of unit tests as well.

Comment by Dirk Geurs [ 30/Dec/14 9:51 AM ]

I have added some tests for the changes made earlier.

Comment by Aaron Brooks [ 13/Dec/17 5:58 PM ]

Is there something that is needed for these patches to be applied? I run into this semi-regularly.

Comment by Alex Miller [ 13/Dec/17 9:40 PM ]

Sorry, has just never been looked at afaik. Votes help raise visibility.





[CLJ-2075] Add three-arities to < <= > >= = == not= Created: 03/Dec/16  Updated: 16/May/17

Status: Reopened
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Nikita Prokopov Assignee: Unassigned
Resolution: Unresolved Votes: 10
Labels: None

Attachments: Text File clj-2075-add-three-arities-to-comparisons-3.patch    
Patch: Code
Approval: Triaged

 Description   

In my practice, using three-arities of less/greater operations is pretty common for e.g. checking a number is in range:

(< 0 temp 100)

The problem is, it is almost three times as slow compared to (and (< 0 temp) (< temp 100)).

This happens because three-arities are handled by the generic vararg arity branch:

(defn <
  "Returns non-nil if nums are in monotonically increasing order,
  otherwise false."
  {:inline (fn [x y] `(. clojure.lang.Numbers (lt ~x ~y)))
   :inline-arities #{2}
   :added "1.0"}
  ([x] true)
  ([x y] (. clojure.lang.Numbers (lt x y)))
  ([x y & more]
    (if (< x y)
     (if (next more)
       (recur y (first more) (next more))
       (< y (first more)))
     false)

This patch adds special handling for three-arities to these fns: < <= > >= = == not=

(defn <
  "Returns non-nil if nums are in monotonically increasing order,
  otherwise false."
  {:inline (fn [x y] `(. clojure.lang.Numbers (lt ~x ~y)))
   :inline-arities #{2}
   :added "1.0"}
  ([x] true)
  ([x y] (. clojure.lang.Numbers (lt x y)))
  ([x y z] (and (. clojure.lang.Numbers (lt x y))
                (. clojure.lang.Numbers (lt y z))))
  ([x y z & more]
   (if (< x y)
     (let [nmore (next more)]
       (if nmore
         (recur y z (first more) nmore)
         (< y z (first more))))
     false)))

The performance gains are quite significant:

(= 5 5 5) 	 24.508635 ns => 4.802783 ns (-80%)
(not= 1 2 3) 	 122.085793 ns => 21.828776 ns (-82%)
(< 1 2 3) 	 30.842993 ns => 6.714757 ns (-78%)
(<= 1 2 2) 	 30.712399 ns => 6.011326 ns (-80%)
(> 3 2 1) 	 22.577751 ns => 6.893885 ns (-69%)
(>= 3 2 2) 	 21.593219 ns => 6.233540 ns (-71%)
(== 5 5 5) 	 19.700540 ns => 6.066265 ns (-69%)

Higher arities also become faster, mainly because there's one less iteration now:

(= 5 5 5 5) 	 50.264580 ns => 31.361655 ns (-37%)
(< 1 2 3 4) 	 68.059758 ns => 43.684409 ns (-35%)
(<= 1 2 2 4) 	 65.653826 ns => 45.194730 ns (-31%)
(> 3 2 1 0) 	 119.239733 ns => 44.305519 ns (-62%)
(>= 3 2 2 0) 	 65.738453 ns => 44.037442 ns (-33%)
(== 5 5 5 5) 	 50.773521 ns => 33.725097 ns (-33%)

This patch also changes vararg artity of not= to use next/recur instead of apply:

(defn not=
  "Same as (not (= obj1 obj2))"
  {:tag Boolean
   :added "1.0"
   :static true}
  ([x] false)
  ([x y] (not (= x y)))
  ([x y z] (not (= x y z)))
  ([x y z & more]
   (if (= x y)
     (let [nmore (next more)]
       (if nmore
         (recur y z (first more) nmore)
         (not= y z (first more))))
     true)))

Results are good:

(not= 1 2 3 4) 	 130.517439 ns => 29.675640 ns (-77%)

I'm also doing what Jozef Wagner did in CLJ-1912 (calculating (next more) just once), although perf gains from that alone are not that big.

My point here is that optimizing three-arities makes sence because they appear in the real code quite often. Higher arities (4 and more) are much less widespread.



 Comments   
Comment by Nikita Prokopov [ 03/Dec/16 2:32 AM ]

Benchmark code here https://gist.github.com/tonsky/442eda3ba6aa4a71fd67883bb3f61d99

Comment by Alex Miller [ 03/Dec/16 8:24 AM ]

It might make more sense to combine this with CLJ-1912, otherwise these patches will fight.

Comment by Nikita Prokopov [ 03/Dec/16 1:02 PM ]

Use this patch if CLJ-1912 would be applied first

Comment by Nikita Prokopov [ 23/Dec/16 7:50 AM ]

I found a problem with previous patches that during defining = (equality), and is not yet defined. Replaced with if

Comment by Alex Miller [ 15/May/17 3:31 PM ]

Dupe of CLJ-1912

Comment by Nikita Prokopov [ 15/May/17 3:43 PM ]

Alex Miller It is a duplicate, but my patch is waaaaaaaaay faster. Just look at the numbers (70-80% improvement vs 5-10%). It’s because I introduced a real arity so that intermediate collection is not created and is not destructured in case of 3 arguments.

Comment by Jozef Wagner [ 15/May/17 11:55 PM ]

There's a quite serious bug in the supplied patch(es), that causes e.g. (= 3 3 2) to return true. Because of this the benchmarks are flawed too I guess.

Comment by Nikita Prokopov [ 16/May/17 3:13 PM ]

Jozef Wagner thanks for spotting this! Attaching an updated path. Benchmark wasn’t flawed too much because perf gain comes not from doing one less/one more comparison but from not having an overhead of calling a fn with unknown arity.





[CLJ-1852] Clojure-generated class names length exceed file-system limit Created: 20/Nov/15  Updated: 18/Oct/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.7, Release 1.8
Fix Version/s: None

Type: Defect Priority: Major
Reporter: Martin Raison Assignee: Unassigned
Resolution: Unresolved Votes: 10
Labels: compiler
Environment:

tested on CentOS 6


Approval: Triaged

 Description   

Class names generated by the Clojure compiler can be arbitrarily long, exceeding the file system's maximum allowed file name length. For example it happens when you nest functions a bit too deeply:

(defmacro nestfn [n & body]
  (if (> n 0)
    `(fn [] (nestfn ~(- n 1) ~@body))
    body))

(def myf (nestfn 100 "body"))

Compiling this produces a java.io.IOException: File name too long exception.



 Comments   
Comment by Martin Raison [ 20/Nov/15 9:32 PM ]

The Scala community found this issue a while ago, and now the compiler has a max-classfile-name parameter (defaulting to 255). Hashing is used when the limit is exceeded. Maybe we should consider something similar?

Comment by Philipp Neumann [ 16/Oct/17 10:53 AM ]

I tried clojure.core.match with 13 patterns and the compiliation failed under Windows. I assume this problem is the root cause of it.





[CLJ-1451] Add take-until Created: 20/Jun/14  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Alexander Taggart Assignee: Unassigned
Resolution: Unresolved Votes: 10
Labels: transducers

Attachments: Text File 0001-CLJ-1451-add-take-until.patch     Text File 0002-CLJ-1451-add-drop-until.patch     Text File 0003-let-take-until-and-drop-until-return-transducers.patch     Text File CLJ-1451-drop-until.patch     Text File clj-1451.patch     Text File CLJ-1451-take-until.patch    
Approval: Triaged

 Description   

Discussion: https://groups.google.com/d/topic/clojure-dev/NaAuBz6SpkY/discussion

It comes up when I would otherwise use (take-while pred coll), but I need to include the first item for which (pred item) is false.

(take-while pos? [1 2 0 3]) => (1 2)
(take-until zero? [1 2 0 3]) => (1 2 0)

Patch: clj-1451.patch

  • Includes transducer arity of take-until
  • Includes inclusion in transducer generative tests


 Comments   
Comment by Alex Miller [ 20/Jun/14 10:21 AM ]

Patch welcome (w/tests).

Comment by Alexander Taggart [ 20/Jun/14 2:00 PM ]

Impl and tests for take-until and drop-until, one patch for each.

Comment by Jozef Wagner [ 20/Jun/14 3:01 PM ]

Please change :added metadata to "1.7".

Comment by Alexander Taggart [ 20/Jun/14 3:12 PM ]

Updated to :added "1.7"

Comment by John Mastro [ 21/Jun/14 6:26 PM ]

I'd like to propose take-through and drop-through as alternative names. I think "through" communicates more clearly how these differ from take-while and drop-while.

Comment by Andy Fingerhut [ 06/Aug/14 2:27 PM ]

Both patches CLJ-1451-drop-until.patch and CLJ-1451-take-until.patch dated Jun 20 2014 no longer apply cleanly to latest Clojure master due to some changes committed earlier today. I haven't checked whether they are straightforward to update, but would guess that they merely require updating a few lines of diff context.

See the section "Updating stale patches" at http://dev.clojure.org/display/community/Developing+Patches for suggestions on how to update patches.

Comment by Ghadi Shayban [ 13/Nov/14 11:19 PM ]

Would be nice to cover the transducer case too.

Comment by Michael Blume [ 13/Nov/14 11:54 PM ]

rerolled patches

Comment by Michael Blume [ 14/Nov/14 12:11 AM ]

Covered transducer case =)

Comment by Michael Blume [ 14/Nov/14 12:12 AM ]

Actually I like take/drop-through as well

Comment by Ghadi Shayban [ 16/Nov/14 12:41 PM ]

Michael, no volatile/state is necessary in the transducer, like take-while. Just wrap in 'reduced to terminate

Comment by Michael Blume [ 17/Dec/14 6:47 PM ]

a) you're clearly right about take-until

b) seriously I don't know what I was thinking with my take-until implementation, I'm going to claim lack of sleep.

c) I'm confused about how to make drop-until work without a volatile

Comment by Michael Blume [ 18/Dec/14 1:52 AM ]

Ghadi and I discussed this and couldn't think of a use case for drop-until. Are there any?

Here's a new take-until patch, generative tests included.

Open questions:

Is take-until a good name? My biggest concern is that take-until makes it sound like a slight modification of take, but this function reverses the sense of the predicate relative to take.

Comment by Andy Fingerhut [ 08/Jan/15 6:06 PM ]

Michael, while JIRA can handle multiple attachments for the same ticket with the same name, it can get confusing for people trying to determine which one with the same name is meant. Could you remove or rename one of your identically-named attachments? Instructions for deleting patches are in the "Removing patches" section on this wiki page: http://dev.clojure.org/display/community/Developing+Patches

Comment by Alex Miller [ 11/Mar/16 2:49 PM ]

The patch was slightly stale so I updated to apply to master, but it's almost identical. Attribution retained.

Marked as prescreened.

Comment by Ghadi Shayban [ 29/Jun/16 9:01 PM ]

I feel like this is superceded by CLJ-1906

Comment by Ghadi Shayban [ 28/Oct/16 10:56 AM ]

And this is definitely superseded by `halt-when`

Comment by Alex Miller [ 28/Oct/16 2:11 PM ]

It's not lazy but this is one way to write take-until with halt-when:

(defn take-until [p s] (transduce (halt-when p (fn [r h] (conj r h))) conj [] s))
Comment by Steve Miner [ 28/Oct/16 3:00 PM ]

I wanted to suggest: `(sequence (halt-when p conj) s)` but sequence doesn't support stopping short on a reduced value so that won't work.

Comment by Alex Miller [ 28/Oct/16 3:02 PM ]

Yeah, halt-when is a little tricky to use in transducible contexts other than transduce.





[CLJ-1435] 'numerator and 'denominator fail to handle integral values (i.e. N/1) Created: 30/May/14  Updated: 08/Apr/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Aaron Brooks Assignee: Unassigned
Resolution: Unresolved Votes: 10
Labels: math

Attachments: Text File clj-1435.patch    
Patch: Code and Test
Approval: Prescreened

 Description   

Because ratio values reduce to lowest terms and, for integral values where the lowest term is N/1, are auto-converted to BigInts (and formerly Longs), the current behavior of clojure.core/numerator and clojure.core/denominator yield unexpected results.

user=> (numerator 1/3)
1
user=> (numerator (+ 1/3 2/3))

ClassCastException clojure.lang.BigInt cannot be cast to clojure.lang.Ratio  clojure.core/numerator (core.clj:3306)
user=> (denominator 1/3)
3
user=> (denominator (+ 1/3 2/3))

ClassCastException clojure.lang.BigInt cannot be cast to clojure.lang.Ratio  clojure.core/denominator (core.clj:3314)
user=>

It's confusing to not support numerator and denominator on integer types as this requires you to always check ratio? before invoking them.

Proposed: Extend numerator and denominator to also work on integer types (long, BigInt, BigInteger) by routing to overloaded methods on Numbers for the desired types.

Patch: clj-1435.patch

Prescreening questions:

1. numerator and denominator are tagged as returning java.math.BigInteger (not clojure.lang.BigInt) and that's what I followed in the patch. Seems like maybe that should be BigInt though? Not sure on what basis to make that decision.
2. Should numerator and denominator accept both BigInteger and BigInt?



 Comments   
Comment by Andy Fingerhut [ 30/May/14 6:35 PM ]

I don't know the official stance on this ticket, but will add some notes.

Aaron, numerator and denominator are pretty clearly documented to work on Ratio types only.

It is pretty easy to write my-numerator and my-denominator that work exactly as you wish, checking for the type of arg and using numerator, denominator for Ratio types, and doing whatever you think is correct for other numeric types.

Comment by Aaron Brooks [ 30/May/14 7:44 PM ]

I'm aware that they are documented as such. Part of my point is that you can be working entirely with Ratio types and, via arithmetic operations between them, sometimes wind up with a non-Ratio number unexpectedly.

Also consider:

user=> (numerator 2/1)
ClassCastException java.lang.Long cannot be cast to clojure.lang.Ratio  clojure.core/numerator (core.clj:3238)

You're then left either implementing a try/catch correction or always checking the type before using numerator or denominator which is a loss in performance.

The patch I have in mind is creating a protocol, extended to Ratio, BigInt and Long which calls the appropriate method (Ratios) or returns either the given number or 1 (numerator/denominator) for the integral types. I expect this to maintain the current level of performance in the cases where it works and behave properly in the cases currently not handled.

Comment by Gary Fredericks [ 27/Aug/15 10:38 AM ]

I've definitely written the helper functions Andy describes on several occasions.

Comment by Felipe Micaroni Lalli [ 01/Sep/15 4:58 PM ]

Related issue: https://stackoverflow.com/questions/25194809/how-to-convert-any-number-to-a-clojure-lang-ratio-type-in-clojure

A workaround to that is (numerator (clojure.lang.Numbers/toRatio (rationalize <put any type of number here>)))

Comment by Alex Miller [ 04/Nov/16 9:16 AM ]

I agree with the intent of the ticket here that these should work. I'm not sure about the protocol approach as that would be an open system and I'm not sure that's what we want. An alternative would be to just create Java methods on Numbers that took the appropriate types and let the JVM sort it out.

Comment by Aaron Brooks [ 08/Apr/17 12:38 PM ]

Any progress on this?

Comment by Alex Miller [ 08/Apr/17 1:28 PM ]

Sitting in the queue, waiting for love.

Comment by Aaron Brooks [ 08/Apr/17 3:54 PM ]

Can I give it love? If there's a direction that we can agree on, I'd be happy to create the patch.

Comment by Alex Miller [ 08/Apr/17 6:13 PM ]

I've screeened the patch that's here already?





[CLJ-1152] PermGen leak in multimethods and protocol fns when evaled Created: 30/Jan/13  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.4
Fix Version/s: Release 1.10

Type: Defect Priority: Major
Reporter: Chouser Assignee: Unassigned
Resolution: Unresolved Votes: 10
Labels: memory, protocols

Attachments: File naive-lru-for-multimethods-and-protocols.diff     File protocol_multifn_weak_ref_cache.diff    
Patch: Code
Approval: Incomplete

 Description   

There is a PermGen memory leak that we have tracked down to protocol methods and multimethods called inside an eval, because of the caches these methods use. The problem only arises when the value being cached is an instance of a class (such as a function or reify) that was defined inside the eval. Thus extending IFn or dispatching a multimethod on an IFn are likely triggers.

Reproducing: The easiest way that I have found to test this is to set "-XX:MaxPermSize" to a reasonable value so you don't have to wait too long for the PermGen spaaaaace to fill up, and to use "-XX:+TraceClassLoading" and "-XX:+TraceClassUnloading" to see the classes being loaded and unloaded.

leiningen project.clj
(defproject permgen-scratch "0.1.0-SNAPSHOT"
  :dependencies [[org.clojure/clojure "1.5.0-RC1"]]
  :jvm-opts ["-XX:MaxPermSize=32M"
             "-XX:+TraceClassLoading"
             "-XX:+TraceClassUnloading"])

You can use lein swank 45678 and connect with slime in emacs via M-x slime-connect.

To monitor the PermGen usage, you can find the Java process to watch with "jps -lmvV" and then run "jstat -gcold <PROCESS_ID> 1s". According to the jstat docs, the first column (PC) is the "Current permanent space capacity (KB)" and the second column (PU) is the "Permanent space utilization (KB)". VisualVM is also a nice tool for monitoring this.

Multimethod leak

Evaluating the following code will run a loop that eval's (take* (fn foo [])).

multimethod leak
(defmulti take* (fn [a] (type a)))

(defmethod take* clojure.lang.Fn
  [a]
  '())

(def stop (atom false))
(def sleep-duration (atom 1000))

(defn run-loop []
  (when-not @stop
    (eval '(take* (fn foo [])))
    (Thread/sleep @sleep-duration)
    (recur)))

(future (run-loop))

(reset! sleep-duration 0)

In the lein swank session, you will see many lines like below listing the classes being created and loaded.

[Loaded user$eval15802$foo__15803 from __JVM_DefineClass__]
[Loaded user$eval15802 from __JVM_DefineClass__]

These lines will stop once the PermGen space fills up.

In the jstat monitoring, you'll see the amount of used PermGen space (PU) increase to the max and stay there.

-    PC       PU        OC          OU       YGC    FGC    FGCT     GCT
 31616.0  31552.7    365952.0         0.0      4     0    0.000    0.129
 32000.0  31914.0    365952.0         0.0      4     0    0.000    0.129
 32768.0  32635.5    365952.0         0.0      4     0    0.000    0.129
 32768.0  32767.6    365952.0      1872.0      5     1    0.000    0.177
 32768.0  32108.2    291008.0     23681.8      6     2    0.827    1.006
 32768.0  32470.4    291008.0     23681.8      6     2    0.827    1.006
 32768.0  32767.2    698880.0     24013.8      8     4    1.073    1.258
 32768.0  32767.2    698880.0     24013.8      8     4    1.073    1.258
 32768.0  32767.2    698880.0     24013.8      8     4    1.073    1.258

A workaround is to run prefer-method before the PermGen space is all used up, e.g.

(prefer-method take* clojure.lang.Fn java.lang.Object)

Then, when the used PermGen space is close to the max, in the lein swank session, you will see the classes created by the eval'ing being unloaded.

[Unloading class user$eval5950$foo__5951]
[Unloading class user$eval3814]
[Unloading class user$eval2902$foo__2903]
[Unloading class user$eval13414]

In the jstat monitoring, there will be a long pause when used PermGen space stays close to the max, and then it will drop down, and start increasing again when more eval'ing occurs.

-    PC       PU        OC          OU       YGC    FGC    FGCT     GCT
 32768.0  32767.9    159680.0     24573.4      6     2    0.167    0.391
 32768.0  32767.9    159680.0     24573.4      6     2    0.167    0.391
 32768.0  17891.3    283776.0     17243.9      6     2   50.589   50.813
 32768.0  18254.2    283776.0     17243.9      6     2   50.589   50.813

The defmulti defines a cache that uses the dispatch values as keys. Each eval call in the loop defines a new foo class which is then added to the cache when take* is called, preventing the class from ever being GCed.

The prefer-method workaround works because it calls clojure.lang.MultiFn.preferMethod, which calls the private MultiFn.resetCache method, which completely empties the cache.

Protocol leak

The leak with protocol methods similarly involves a cache. You see essentially the same behavior as the multimethod leak if you run the following code using protocols.

protocol leak
(defprotocol ITake (take* [a]))

(extend-type clojure.lang.Fn
  ITake
  (take* [this] '()))

(def stop (atom false))
(def sleep-duration (atom 1000))

(defn run-loop []
  (when-not @stop
    (eval '(take* (fn foo [])))
    (Thread/sleep @sleep-duration)
    (recur)))

(future (run-loop))

(reset! sleep-duration 0)

Again, the cache is in the take* method itself, using each new foo class as a key.

Workaround: A workaround is to run -reset-methods on the protocol before the PermGen space is all used up, e.g.

(-reset-methods ITake)

This works because -reset-methods replaces the cache with an empty MethodImplCache.

Patch: protocol_multifn_weak_ref_cache.diff

Screened by:



 Comments   
Comment by Chouser [ 30/Jan/13 9:10 AM ]

I think the most obvious solution would be to constrain the size of the cache. Adding an item to the cache is already not the fastest path, so a bit more work could be done to prevent the cache from growing indefinitely large.

That does raise the question of what criteria to use. Keep the first n entries? Keep the n most recently used (which would require bookkeeping in the fast cache-hit path)? Keep the n most recently added?

Comment by Jamie Stephens [ 18/Oct/13 9:35 AM ]

At a minimum, perhaps a switch to disable the caches – with obvious performance impact caveats.

Seems like expensive LRU logic is probably the way to go, but maybe don't have it kick in fully until some threshold is crossed.

Comment by Alex Miller [ 18/Oct/13 4:28 PM ]

A report seeing this in production from mailing list:
https://groups.google.com/forum/#!topic/clojure/_n3HipchjCc

Comment by Adrian Medina [ 10/Dec/13 11:43 AM ]

So this is why we've been running into PermGen space exceptions! This is a fairly critical bug for us - I'm making extensive use of multimethods in our codebase and this exception will creep in at runtime randomly.

Comment by Kevin Downey [ 17/Apr/14 9:52 PM ]

it might be better to split this in to two issues, because at a very abstract level the two issues are the "same", but concretely they are distinct (protocols don't really share code paths with multimethods), keeping them together in one issue seems like a recipe for a large hard to read patch

Comment by Kevin Downey [ 26/Jul/14 5:49 PM ]

naive-lru-method-cache-for-multimethods.diff replaces the methodCache in multimethods with a very naive lru cache built on PersistentHashMap and PersistentQueue

Comment by Kevin Downey [ 28/Jul/14 7:09 PM ]

naive-lru-for-multimethods-and-protocols.diff creates a new class clojure.lang.LRUCache that provides an lru cache built using PHashMap and PQueue behind an IPMap interface.

changes MultiFn to use an LRUCache for its method cache.

changes expand-method-impl-cache to use an LRUCache for MethodImplCache's map case

Comment by Kevin Downey [ 30/Jul/14 3:10 PM ]

I suspect my patch naive-lru-for-multimethods-and-protocols.diff is just wrong, unless MethodImplCache really is being used as a cache we can't just toss out entries when it gets full.

looking at the deftype code again, it does look like MethidImplCache is being used as a cache, so maybe the patch is fine

if I am sure of anything it is that I am unsure so hopefully someone who is sure can chime in

Comment by Nicola Mometto [ 31/Jul/14 11:02 AM ]

I haven't looked at your patch, but I can confirm that the MethodImplCache in the protocol function is just being used as a cache

Comment by dennis zhuang [ 08/Aug/14 6:21 AM ]

I developed a new patch that convert the methodCache in MultiFn to use WeakReference for dispatch value,and clear the cache if necessary.

I've test it with the code in ticket,and it looks fine.The classes will be unloaded when perm gen is almost all used up.

Comment by Alex Miller [ 22/Aug/14 4:55 PM ]

I don't know which to evaluate here. Does multifn_weak_method_cache.diff supersede naive-lru-for-multimethods-and-protocols.diff or are these alternate approaches both under consideration?

Comment by Kevin Downey [ 22/Aug/14 8:26 PM ]

the most straight forward thing, I think, is to consider them as alternatives, I am not a huge fan of weakrefs, but of course not using weakrefs we have to pick some bounding size for the cache, and the cache has a strong reference that could prevent a gc, so there are trade offs. My reasons to stay away from weak refs in general are using them ties the behavior of whatever you are building to the behavior of the gc pretty strongly. that may be considered a matter of personal taste

Comment by Andy Fingerhut [ 29/Aug/14 4:31 PM ]

All patches dated Aug 8 2014 and earlier no longer applied cleanly to latest master after some commits were made to Clojure on Aug 29, 2014. They did apply cleanly before that day.

I have not checked how easy or difficult it might be to update the patches.

Comment by Kevin Downey [ 29/Aug/14 7:00 PM ]

I've updated naive-lru-for-multimethods-and-protocols.diff to apply to the current master

Comment by Andy Fingerhut [ 29/Aug/14 7:34 PM ]

Thanks, Kevin. While JIRA allows multiple attachments to a ticket with the same filename but different contents, that can be confusing for people looking for a particular patch, and for a program I have that evaluates patches for things like whether they apply and build cleanly. Would you mind removing the older one, or in some other way making all the names unique?

Comment by Kevin Downey [ 29/Aug/14 8:43 PM ]

I deleted all of my attachments accept for my latest and greatest

Comment by dennis zhuang [ 30/Aug/14 9:51 AM ]

I updated multifn_weak_method_cache2.diff patch too.

I think using weak reference cache is better,because we have to keep one cache per multifn.When you have many multi-functions, there will be many LRU caches in memory,and they will consume too much memory and CPU for evictions. You can't choose a proper threshold for LRU cache in every environment.
But i don't have any benchmark data to support my opinion.

Comment by Alex Miller [ 10/Sep/14 2:38 PM ]

I'm going to set the LRU cache patch aside. I don't think it's possible to find a "correct" size for it and it seems weird to me to extend APersistentMap to build such a thing anyways.

I think it makes more sense to follow the same strategy used for other caches (such as the Keyword cache) - a combination ConcurrentHashMap with WeakReferences and a ReferenceQueue for clean-up. I don't see any compelling reason not to take the same path as other internal caches.

Comment by Alex Miller [ 10/Sep/14 3:44 PM ]

Stepping back a little to think about the problem.... our requirements are:
1) cache map of dispatch value (could be any Object) to multimethod function (IFn)
2) do we want keys to be compared based on equality or identity? identity-based opens up more reference-based caching options and is fine for most common dispatch types (Class, Keyword), but reduces (often eliminates?) cache hits for all other types where values are likely to be equiv but not identical (vector of strings for example)
3) concurrent access to cache
4) cache cannot grow without bound
5) cache cannot retain strong references to dispatch values (the cache keys) because the keys might be instances of classes that were loaded in another classloader which will prevent GC in permgen

multifn_weak_method_cache.diff uses a ConcurrentHashMap (#3) that maps RefWrapper around keys to IFn (#1). The patch uses Util.equals() (#2) for (Java) equality-based comparisons. The RefWrapper wraps them in WeakReferences to avoid #5. Cache clearing based on the ReferenceQueue is used to prevent #4.

A few things definitely need to be fixed:

  • Util.equals() should be Util.equiv()
  • methodCache and rq should be final
  • Why does RefWrapper have obj and expect rq to possibly be null?
  • RefWrapper fields should all be final
  • Whitespace errors in patch

Another idea entirely - instead of caching dispatch value, cache based on hasheq of dispatch value then equality check on value. Could then use WeakHashMap and no RefWrapper.

This patch does not cover the protocol cache. Is that just waiting for the multimethod case to look good?

Comment by dennis zhuang [ 10/Sep/14 7:18 PM ]

Hi, alex, thanks for your review.But the latest patch is multifn_weak_method_cache2.diff. I will update the patch soon by your review, but i have a few questions to be explained.

1) I will use Util.equiv() instead of Util.equals().But what's the difference of them?
2) When the RefWrapper is retained as key in ConcurrentHashMap, it wraps the obj in WeakReference.But when trying to find it in ConcurrentHashMap, it uses obj directly as strong reference, and create it with passing null ReferenceQueue.Please look at the multifn_weak_method_cache2.diff line number 112. It short, the patch stores the dispatch value as weak reference in cache,but uses strong reference for cache getting.

3) If caching dispatch value based on hasheq , can we avoid hasheq value conflicts? If two different dispatch value have a same hasheq( or why it doesn't happen?), we would be in trouble.

Sorry, the patch doesn't cover the protocol cache, i will add it ASAP.

Comment by dennis zhuang [ 11/Sep/14 2:02 AM ]

The new patch 'protocol_multifn_weak_ref_cache.diff' is uploaded.

1) Using Util.equiv() instead of Util.equals()
2) Moved the RefWrapper and it's associated methods to Util.java, and refactor the code based on alex's review.
3) Fixed whitespace errors.
4) Fixed PermGen leak in protocol fns.

Comment by Alex Miller [ 03/Oct/14 10:35 AM ]

I screened this ticket again with Brenton Ashworth and had the following comments:

1) We need to have a performance test to verify that we have not negatively impacted performance of multimethods or protocol invocation.
2) Because there are special cases around null keys in the multimethod cache, please verify that there are existing example tests using null dispatch values in the existing test coverage.
3) In Util$RefWrapper.getObj() - why does this return this.ref at the end? It was not clear to me that the comment was correct or that this was useful in any way.
4) In Util$RefWrapper.clearRefWrapCache() - can k == null in that if check? If not, can we omit that? Also, if you explicitly create the Iterator from the entry set, you can call .remove() on it more efficiently than calling .remove() on the cache itself.
5) In core_deftype / MethodImplCache, it appears that you are modifying a now-mutable field rather than the prior version that was going to great lengths to stay immutable. It's not clear to me what the implications of this change are and that concerns me. Can it use a different collection or code to stay immutable?
6) Please update the description of this ticket to include an approach section that describes the changes we are making.

Thanks!





[CLJ-1452] clojure.core/*rand* for seedable randomness Created: 20/Jun/14  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Gary Fredericks Assignee: Unassigned
Resolution: Unresolved Votes: 9
Labels: math

Attachments: Text File CLJ-1452.patch    
Approval: Triaged

 Description   

Clojure's random functions currently use Math.random and related features, which makes them impossible to seed. This seems like an appropriate use of a dynamic var (compared to extra arguments), since library code that wants to behave randomly could transparently support seeding without any extra effort.

I propose (def ^:dynamic *rand* (java.util.Random.)) in clojure.core, and that rand, rand-int, rand-nth, and shuffle be updated to use *rand*.

I think semantically this will not be a breaking change.

Criterium Benchmarks

I did some benchmarking to try to get an idea of the performance implications of using a dynamic var, as well as to measure the changes to concurrent access.

The code used is at https://github.com/gfredericks/clj-1452-tests; the raw output is in a comment.

rand is slightly slower, while shuffle is insignificantly faster. Using shuffle from 8 threads is insignificantly slower, but switching to a ThreadLocalRandom manually in the patched version results in a 2.5x speedup.

Running on my 8 core Linode VM:

Benchmark Clojure Runtime mean Runtime std dev
rand 1.6.0 61.3ns 7.06ns
rand 1.6.0 + *rand* 63.7ns 1.80ns
shuffle 1.6.0 12.9µs 251ns
shuffle 1.6.0 + *rand* 12.8µs 241ns
threaded-shuffling 1.6.0 151ms 2.31ms
threaded-shuffling 1.6.0 + *rand* 152ms 8.77ms
threaded-local-shuffling 1.6.0 N/A N/A
threaded-local-shuffling 1.6.0 + *rand* 64.5ms 1.41ms

Approach: create a dynamic var *rand* and update rand, rand-int, rand-nth, and shuffle to use *rand*

Patch: CLJ-1452.patch

Screened by:



 Comments   
Comment by Gary Fredericks [ 21/Jun/14 7:50 PM ]

Attached CLJ-1452.patch, with the same code used in the benchmarks.

Comment by Gary Fredericks [ 23/Jun/14 8:34 AM ]

Should we be trying to make Clojure's random functions thread-local by default while we're mucking with this stuff? We could have a custom subclass of Random that has ThreadLocal logic in it (avoiding ThreadLocalRandom because Java 6), and make that the default value of *rand*.

Comment by Alex Miller [ 28/Dec/14 11:04 AM ]

I think the ThreadLocal question is interesting, not sure re answer.

It would be nice if the description summarized the results of the tests in a table and the criterium output was in the comments instead.

Comment by Gary Fredericks [ 30/Dec/14 1:26 PM ]

Full output from the test repo (which is summarized in the table in the description):

$ echo "Clojure 1.6.0"; lein with-profile +clj-1.6 run; echo "Clojure 1.6.0 with *rand*"; lein with-profile +clj-1452 run
Clojure 1.6.0

;;;;;;;;;;;;;;;;;;
;; Testing rand ;;
;;;;;;;;;;;;;;;;;;
WARNING: Final GC required 1.261632096547911 % of runtime
Evaluation count : 644646900 in 60 samples of 10744115 calls.
             Execution time mean : 61.297605 ns
    Execution time std-deviation : 7.057249 ns
   Execution time lower quantile : 56.872437 ns ( 2.5%)
   Execution time upper quantile : 84.483045 ns (97.5%)
                   Overhead used : 16.319772 ns

Found 6 outliers in 60 samples (10.0000 %)
    low-severe   1 (1.6667 %)
    low-mild     5 (8.3333 %)
 Variance from outliers : 75.5119 % Variance is severely inflated by outliers

;;;;;;;;;;;;;;;;;;;;;
;; Testing shuffle ;;
;;;;;;;;;;;;;;;;;;;;;
Evaluation count : 4780800 in 60 samples of 79680 calls.
             Execution time mean : 12.873832 µs
    Execution time std-deviation : 251.388257 ns
   Execution time lower quantile : 12.526871 µs ( 2.5%)
   Execution time upper quantile : 13.417559 µs (97.5%)
                   Overhead used : 16.319772 ns

Found 3 outliers in 60 samples (5.0000 %)
    low-severe   3 (5.0000 %)
 Variance from outliers : 7.8591 % Variance is slightly inflated by outliers

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Testing threaded-shuffling ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Evaluation count : 420 in 60 samples of 7 calls.
             Execution time mean : 150.863290 ms
    Execution time std-deviation : 2.313755 ms
   Execution time lower quantile : 146.621548 ms ( 2.5%)
   Execution time upper quantile : 155.218897 ms (97.5%)
                   Overhead used : 16.319772 ns
Clojure 1.6.0 with *rand*

;;;;;;;;;;;;;;;;;;
;; Testing rand ;;
;;;;;;;;;;;;;;;;;;
Evaluation count : 781707720 in 60 samples of 13028462 calls.
             Execution time mean : 63.679152 ns
    Execution time std-deviation : 1.798245 ns
   Execution time lower quantile : 61.414851 ns ( 2.5%)
   Execution time upper quantile : 67.412204 ns (97.5%)
                   Overhead used : 13.008428 ns

Found 3 outliers in 60 samples (5.0000 %)
    low-severe   3 (5.0000 %)
 Variance from outliers : 15.7596 % Variance is moderately inflated by outliers

;;;;;;;;;;;;;;;;;;;;;
;; Testing shuffle ;;
;;;;;;;;;;;;;;;;;;;;;
Evaluation count : 4757940 in 60 samples of 79299 calls.
             Execution time mean : 12.780391 µs
    Execution time std-deviation : 240.542151 ns
   Execution time lower quantile : 12.450218 µs ( 2.5%)
   Execution time upper quantile : 13.286910 µs (97.5%)
                   Overhead used : 13.008428 ns

Found 1 outliers in 60 samples (1.6667 %)
    low-severe   1 (1.6667 %)
 Variance from outliers : 7.8228 % Variance is slightly inflated by outliers

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Testing threaded-shuffling ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Evaluation count : 420 in 60 samples of 7 calls.
             Execution time mean : 152.471310 ms
    Execution time std-deviation : 8.769236 ms
   Execution time lower quantile : 147.954789 ms ( 2.5%)
   Execution time upper quantile : 161.277200 ms (97.5%)
                   Overhead used : 13.008428 ns

Found 3 outliers in 60 samples (5.0000 %)
    low-severe   3 (5.0000 %)
 Variance from outliers : 43.4058 % Variance is moderately inflated by outliers

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Testing threaded-local-shuffling ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Evaluation count : 960 in 60 samples of 16 calls.
             Execution time mean : 64.462853 ms
    Execution time std-deviation : 1.407808 ms
   Execution time lower quantile : 62.353265 ms ( 2.5%)
   Execution time upper quantile : 67.197368 ms (97.5%)
                   Overhead used : 13.008428 ns

Found 1 outliers in 60 samples (1.6667 %)
    low-severe   1 (1.6667 %)
 Variance from outliers : 9.4540 % Variance is slightly inflated by outliers
Comment by Gary Fredericks [ 30/Dec/14 1:28 PM ]

I think using a ThreadLocal is logically independent from adding *rand*, so it could be a separate ticket. I just suggested it here since it would for some uses mitigate any slowdown from *rand* but now that I'm looking at the benchmark results again the slowdown might be insignificant.

Comment by Gary Fredericks [ 30/Dec/14 5:44 PM ]

Also worth noting that (as I did in the benchmark code) with just the patch's changes (i.e., no ThreadLocal involved) users still gain the ability to do ThreadLocal manually, which is not currently possible.

Comment by Stuart Halloway [ 19/Jul/15 7:42 AM ]

workaround: data.generators provides seedable random

Comment by Ghadi Shayban [ 14/Jan/16 10:15 AM ]

Just noting, ThreadLocalRandom is >= JDK 7.





[CLJ-1278] State function's unmunged full name in compiled function's toString() Created: 10/Oct/13  Updated: 17/May/15

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Howard Lewis Ship Assignee: Unassigned
Resolution: Unresolved Votes: 9
Labels: errormsgs, interop

Attachments: Text File CLJ-1278-2.patch     Text File CLJ-1528--function-tostring.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Currently function instances print their toString() with the munged Java name:

user=> (ns proj.util-fns)
nil
proj.util-fns=> (defn a->b [a] (inc a))
#'proj.util-fns/a->b
proj.util-fns=> a->b
#object[proj.util_fns$a__GT_b 0x141ba1f1 "proj.util_fns$a__GT_b@141ba1f1"]

For debugging purposes, it would be useful to have the function toString() describe the Clojure-oriented fn name.

Approach: Store the original name in the function instance and use it in the toString() rather than returning the class name.

proj.util-fns=> a->b
#object[proj.util_fns$a__GT_b 0x47d1a507 "proj.util-fns/a->b(NO_SOURCE_FILE:2)"]

Tradeoffs: Increased function instance size for the function name.

Patch: CLJ-1278-2.patch



 Comments   
Comment by Howard Lewis Ship [ 10/Oct/13 8:39 PM ]

Contains changes and updated tests. I don't have any details on if this affects compiler performance or generated code size in any significant or even measurable way.

Comment by Andy Fingerhut [ 11/Oct/13 4:06 PM ]

Howard, sorry I do not have more useful comments on the changes you make in your patch. Right now I only have a couple of minor comments on its form. The preferred format for patches is that created using the instructions shown on this wiki page: http://dev.clojure.org/display/community/Developing+Patches

Also, there are several parts of your patch that appear to only make changes in the whitespace of lines. It would be best to leave such changes out of a proposed patch.

Comment by Howard Lewis Ship [ 11/Oct/13 5:00 PM ]

Yes, I didn't notice the whitespace changes until after; I must have hit reformat at some point, despite my best efforts. I'll put together a new patch shortly.

Comment by Howard Lewis Ship [ 11/Oct/13 6:26 PM ]

Clean patch

Comment by Howard Lewis Ship [ 25/Nov/14 6:00 PM ]

FYI, it's been a year. The correct file is CLJ-1278-2.patch.

Comment by Howard Lewis Ship [ 25/Nov/14 6:07 PM ]

... hm, something's changed in recent times.

     [java] FAIL in (fn-toString) (fn.clj:83)
     [java] nested functions
     [java] expected: (= (simple-name (.toString (factory-function))) (str "clojure.test-clojure.fn/" "factory-function/fn"))
     [java]   actual: (not (= "clojure.test-clojure.fn/factory-function/fn__7565" "clojure.test-clojure.fn/factory-function/fn"))
     [java]
     [java] FAIL in (fn-toString) (fn.clj:83)
     [java] nested functions
     [java] expected: (= (simple-name (.toString (named-factory-function))) (str "clojure.test-clojure.fn/" "named-factory-function/a-function-name"))
     [java]   actual: (not (= "clojure.test-clojure.fn/named-factory-function/a-function-name__7568" "clojure.test-clojure.fn/named-factory-function/a-function-name"))

I'd be willing to update my patch if there's any indication that it will ever be picked up. It's been over a year since last update.

Comment by Andy Fingerhut [ 26/Nov/14 10:30 AM ]

The change in behavior you are seeing is most likely due to a fix for ticket CLJ-1330.

And in case you were wondering, no, I am not the person who knows what tickets are of interest. I know that this one has gotten a fair number of votes, and by votes is one of the top ranked enhancement suggestions - look under "enhancements" on this report, or search for 1330: http://jafingerhut.github.io/clj-ticket-status/CLJ-top-tickets-by-weighted-vote.html

The features going into Clojure 1.7 are pretty well decided upon, and a fair number of other fixes and enhancements were delayed to 1.8. A longer than 1 year wait is not unusual, especially for enhancements.

Comment by Howard Lewis Ship [ 26/Nov/14 3:06 PM ]

Thanks for the info; don't want to come off as whiny but The Great Silence is off putting to someone who wants to help improve things.

I'll update my patch, and hope to see some motion for 1.8.

Comment by Alex Miller [ 26/Nov/14 3:43 PM ]

There are ~400 open tickets for Clojure. As a printing enhancement, this is generally considered lower priority than defects. Additionally, the proposal changes the compiler, bytecode generation code, and adds fields to generated objects, which has unassessed and potentially wide impacts. The combination of these things means it might be a while before we get around to looking at it.

Things that you could do to help:
1) Simplify the description. Someone coming to this ticket (screeners and ultimately Rich) want to look at the description and get the maximal understanding with the minimal effort. We have some guidelines on this at http://dev.clojure.org/display/community/Creating+Tickets if you haven't seen it. For an enhancement, a short (1-2 sentence) description of the problem and an example I can run in the repl is best. Then a proposal (again, as short as possible). Examples: CLJ-1529, CLJ-1325, CLJ-1378. For an enhancement like this, seeing (succinct) before/after versions where a user will see this is often the quickest way for a screener to understand the benefit.

2) Anticipate and remove blockers. As I mentioned above, you are changing the size of every function object. What is the impact on size and construction time? Providing data and/or a test harness saves a screener from doing this work. It's better to leave details in attachments or comments and refer to it in the description if it's lengthy.

3) Have others screen (per http://dev.clojure.org/display/community/Screening+Tickets ) - while that is the job a screener (often me) will have to re-do, having more eyeballs on it early helps. Ask on #clojure for someone else to take a look, try it, etc. If there are open questions, leaving those in the description helps guide my work.

Comment by Howard Lewis Ship [ 26/Nov/14 4:09 PM ]

Alex, thanks for the advice. I'll follow through. Some of that data is already present, but I can make it more prominent.

I know that I'm overwhelmed by the number of issues (including enhancements and minor improvements) on the Tapestry issue list, so I'm understanding of problem space.

Comment by Steve Miner [ 17/May/15 9:06 AM ]

You could instead implement toString() on something like AFn.java.

public String toString() {
    String name = getClass().getSimpleName();
    return Compiler.demunge(name);
}
Comment by Alex Miller [ 17/May/15 11:06 AM ]

Munge+demunge is a lossy operation. Consider demunge as "best effort", not something to rely on.





[CLJ-2041] clojure.spec/keys requires input collections conform to clojure.core/map? Created: 11/Oct/16  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: Release 1.10

Type: Defect Priority: Minor
Reporter: Timothy Baldridge Assignee: Unassigned
Resolution: Unresolved Votes: 9
Labels: spec

Approval: Vetted

 Description   

I would like to use specs to validate Datomic entities. However, `s/keys` is too restrictive in that it requires input collections to conform to `clojure.core/map?` instead of some more primitive interface (for example clojure.lang.ILookup or clojure.lang.Associative).



 Comments   
Comment by Alex Miller [ 04/Nov/16 8:21 AM ]

s/keys uses IPersistentMap's Iterable support for iterating through all entries for validation. ILookup and Associative do not support iteration. So, that's why it is the way it is. But, understand the desire.

Comment by Alex Miller [ 04/Nov/16 8:34 AM ]

Datomic entities are seqable so maybe that's a potential path (would be slower for actual PHMs though).

Comment by Odin Standal [ 04/Nov/16 8:35 AM ]

Thanks for following up. So any ideas or guidance on how to use clojure.spec with Datomic entities?

Comment by Alex Miller [ 04/Nov/16 8:37 AM ]

For now, you could use into to pour an entity into a PHM before validating. I hesitate to suggest it, but that could even be in the spec with a leading conformer.

Comment by Alex Miller [ 14/Nov/16 12:16 PM ]

Moving this into 1.9 for the moment just so we don't lose it. Not sure whether we can or will actually do anything with this though.

Comment by Alex Miller [ 08/Mar/17 10:00 AM ]

This is related to CLJ-2080 as it's the same basic issue of what map-of and every-kv actually expect as valid inputs, which is: something that seqs to map entries. We can't really write a predicate for it without an interface "ISeqsToMapEntries" (intentionally bad name) to indicate this. java.util.Map, IPersistentMap, etc imply this, but an object can seq to map entries without meeting all the constraints of those much broader interfaces. ILookup does not and should not imply this.





[CLJ-1490] Exception on protocol implementation after protocol reloaded could be improved Created: 04/Aug/14  Updated: 07/Nov/14

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: Howard Lewis Ship Assignee: Unassigned
Resolution: Unresolved Votes: 9
Labels: errormsgs, protocols

Attachments: Text File CLJ-1490.1.patch    
Patch: Code and Test
Approval: Triaged

 Description   

In a situation where you define a protocol, and then define a class that extends that protocol (e.g., reify, defrecord, deftype) and then later, re-define the protocol (typically, by reloading the namespace that defines the protocol), then the existing instances are no longer valid.

However, the exception that gets generated can be confusing:

     java.lang.IllegalArgumentException: No implementation of method: :injections of protocol: #'fan.microservice/MicroService found for class: fan.auth.AuthService
                                           clojure.core/-cache-protocol-fn                  core_deftype.clj:  544
                                           fan.microservice/eval23300/fn/G                  microservice.clj:   12
                                                       clojure.core/map/fn                          core.clj: 2559
                                                 clojure.lang.LazySeq.sval                      LazySeq.java:   40
                                                  clojure.lang.LazySeq.seq                      LazySeq.java:   49
                                                    clojure.lang.Cons.next                         Cons.java:   39
                                             clojure.lang.RT.boundedLength                           RT.java: 1654
                                               clojure.lang.RestFn.applyTo                       RestFn.java:  130
                                                        clojure.core/apply                          core.clj:  626
                 fan.microservice.StandardContainer/construct-ring-handler                  microservice.clj:   51

The confusing part is that (in the above example) AuthService does extend MicroService, just not the correct version of it.

The exception message should be extended to identify that this is "possibly because the protocol was reloaded since the class was defined."

A patch will be ready shortly.



 Comments   
Comment by Howard Lewis Ship [ 04/Aug/14 12:15 PM ]

Patch with tests





[CLJ-1372] Inconsistent hash with java collections Created: 09/Mar/14  Updated: 12/Jan/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: Backlog

Type: Defect Priority: Minor
Reporter: Jozef Wagner Assignee: Unassigned
Resolution: Unresolved Votes: 9
Labels: collections, interop
Environment:

1.6.0 master


Attachments: Text File 0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M-alternative.patch     Text File 0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch     Text File 0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M-substring.patch     Text File 0005-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch     Text File 0006-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch     Text File 0007-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch     File clj-1372-2.diff     File clj-1372.diff    
Patch: Code and Test
Approval: Vetted

 Description   

c.c/hash always use hashCode for java collections, which is incompatible when comparing with Clojure collections, which use Murmur3.

user=> (== (hash (java.util.ArrayList. [1 2 3])) (hash [1 2 3]))
false
user=> (= (java.util.ArrayList. [1 2 3]) [1 2 3])
true

One way to fix it is to add a special case in Util/hasheq for java.util.Collections, as it is now for Strings.

Link to a discussion of this topic in the Clojure group: https://groups.google.com/forum/#!topic/clojure/dQhdwZsyIEw



 Comments   
Comment by Jozef Wagner [ 09/Mar/14 8:02 AM ]

Same problem for maps, so hasheq should have a special case for java.util.Map too.

Comment by Jozef Wagner [ 09/Mar/14 9:21 AM ]

Added patch with fix for j.u. Map, Set and List.

Comment by Andy Fingerhut [ 09/Mar/14 6:02 PM ]

Add patch clj-1372-2.diff that is identical to Jozef Wagner's clj-1372.diff, except it also adds some new tests that fail without his changes, and pass with them.

Comment by Alex Miller [ 10/Mar/14 9:31 AM ]

I think the contract on equiv/hasheq is more narrowly scoped than this and only applies if both collections are IPersistentCollection. In other words, I don't think this is wanted or required.

Note that the Java .equals/.hashCode contract is maintained here - these collections will compare as .equals() and do have the same .hashCode().

Comment by Jozef Wagner [ 10/Mar/14 9:38 AM ]

Without the patch the following statement is not valid: "If two objects are equal with c.c/=, than their hash returned by c.c/hash is the same number". We can say that this is valid only iff both objects are 'clojure' objects, but this goes against clojures interop principles (interop is easy, fast, no surprises).

Comment by Jozef Wagner [ 10/Mar/14 9:54 AM ]

Manifestation of this bug

user=> (assoc (hash-map [1 2 3] :foo) (java.util.ArrayList. [1 2 3]) :bar)
{[1 2 3] :bar, [1 2 3] :foo}
user=> (get (hash-map [1 2 3] :foo) (java.util.ArrayList. [1 2 3]))
nil
Comment by Alex Miller [ 10/Mar/14 10:58 AM ]

I agree that would be a nice thing to say without qualification.

There is a real cost to adding more branches in hasheq - adding those collection checks affects every hasheq. Running a full Clojure build, I see the following set of classes with >100 occurences where this happens (note that exactly 0 of these are the Java collections - this case doesn't exist in the Clojure build itself):

clojure.lang.Var 107001502
java.lang.Class 2651389
java.lang.Character 2076322 
java.util.UUID 435235 
java.util.Date 430956
clojure.lang.Compiler$LocalBinding 116830
java.lang.Boolean 112361
java.util.regex.Pattern 325

We'd be adding 4 more instanceof checks in the path of every one of those hasheqs. This would also likely blow any JVM inlining.

Rich says "all bets should be off for hasheq/equiv of non-values" where Java collections obviously fall into the class of "non-values".

Comment by Andy Fingerhut [ 10/Mar/14 11:04 AM ]

Would a doc patch be considered? Say one that modified the doc of clojure.core/hash to include a phrase indicating that it is only promised to be consistent with clojure.core/= for immutable values? It could even perhaps mention that Floats are out, too: see CLJ-1036

Comment by Alex Miller [ 10/Mar/14 12:00 PM ]

I think it would be preferred to do any detailed docs about hash at http://clojure.org/data_structures rather than in the docstring. Although the docstring on hash probably could use an update and a pointer to the web site after the latest changes.

Comment by Jozef Wagner [ 10/Mar/14 12:14 PM ]

Neverthless it is a breaking change from 1.5, and it should be mentioned in changelog. What still bugs me is that c.c/= is supported in such cases but the c.c/hash is not. If supporting c.c/hash is expensive, isn't it better to drop support for c.c/= in such cases? It will eliminate surprises such as:

user=> (apply distinct? (hash-set [1 2 3] (java.util.Collections/unmodifiableList [1 2 3])))
false
Comment by Alex Miller [ 10/Mar/14 2:05 PM ]

I'm not sure it's a "breaking" change if something not considered to be guaranteed changes. But I take your point.

I don't think it's feasible to drop = support for Clojure and Java collections - that seems important and useful. And if it were free to do so, I would like to be able to say without qualification that if equiv=true, then hasheq is the same.

It's unclear to me that the examples listed on this ticket are actually real problems people are likely to encounter. The main users of hasheq are hash map and hash set. So to manifest, you would need to be putting a mixture of Clojure and Java collections into one of those, in particular a mixture of collections that compare as equal.

Still thinking about it.

Comment by Jozef Wagner [ 10/Mar/14 3:27 PM ]

Sorry for spamming but there may be another option, to not fallback into hashCode in hasheq, but to instead throw in cases where hasheq is requested for non-values. This will lead to a cleaner separation of hash types. Of course it will prevent putting non-values into hash-set.

Comment by Alex Miller [ 10/Mar/14 3:34 PM ]

There is no simple check for "valueness" though?

Comment by Andy Fingerhut [ 10/Mar/14 3:37 PM ]

An idea, for what it might be worth: Add one test for instance of java.util.Collection in Util.hasheq method instead of 3 separate tests for Set, List, and Map. It doesn't cover Map.Entry.

Comment by Alex Miller [ 10/Mar/14 3:38 PM ]

Map doesn't extend Collection either.

Comment by Stuart Halloway [ 11/Mar/14 10:44 AM ]

I think this needs more consideration and should not hold up 1.6.

Comment by Andy Fingerhut [ 20/Mar/14 2:01 PM ]

Both patches clj-1372.diff and clj-1372-2.diff fail to apply cleanly as of latest Clojure master on Mar 20 2014. They did apply cleanly before the Mar 19 2014 commit, I believe, and the only issue appears to be a changed line of diff context. Given the discussion about whether such a change is desired, it sounds like more thought is needed before deciding what change should be made, if any.

Comment by Mike Anderson [ 11/May/14 2:31 PM ]

This is a pretty bad defect. It absolutely needs to be fixed. It's not really about whether using a mix of Clojure and Java collections is a likely use case or not (it probably isn't...), it's about providing consistent guarantees that people can rely upon.

For example, now I'm really unsure about whether some of the library functions I have that use sets or maps are broken or not. I'd be particularly worried about anything that implements object caches / memoisation / interning based on hashed values. Such code may now have some really nasty subtle defects.

Since they are library functions, I can't guarantee what kind of objects are passed in so the code has to work with all possible inputs (either that or I need to write a clear docstring and throw an exception if the input is not supported).

Comment by Michał Marczyk [ 12/May/14 11:29 PM ]

This patch (0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch) makes hasheq consistent with = for java.util.{List,Map,Map.Entry,Set}. Additionally it extends the special treatment of String (return hasheq of hashCode) to all types not otherwise handled (see below for a comment on this).

It is also available here:

https://github.com/michalmarczyk/clojure/tree/alien-hasheq-2

An earlier version is available here:

https://github.com/michalmarczyk/clojure/tree/alien-hasheq

If I understand correctly, what needs to be benchmarked is primarily the "dispatch time" for clojure.lang.Util/hasheq given a Clojure type. So, I ran a Criterium benchmark repeatedly hashing the same persistent hash map, on the theory that this will measure just the dispatch time on IHashEq instances. I then ran a separate benchmark hashing a PHM, a string and a long and adding up the results with unchecked-add. Hopefully this is a good start; I've no doubt additional benchmarks would be useful.

The results are somewhat surprising to me: hasheq on PHM is actually slightly faster in this benchmark on my build than on 1.6.0; the "add three hasheqs" benchmark is slightly faster on 1.6.0.

;;; 1.6.0

;;; NB. j.u.HM benchmark irrelevant
user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] #_(assert (= (hash phm) (hash juhm))) (c/bench (clojure.lang.Util/hasheq phm)) (c/bench (clojure.lang.Util/hasheq juhm)))
WARNING: Final GC required 1.24405836928592 % of runtime
Evaluation count : 5549560980 in 60 samples of 92492683 calls.
             Execution time mean : 9.229881 ns
    Execution time std-deviation : 0.156716 ns
   Execution time lower quantile : 8.985994 ns ( 2.5%)
   Execution time upper quantile : 9.574039 ns (97.5%)
                   Overhead used : 1.741068 ns

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 2 (3.3333 %)
 Variance from outliers : 6.2652 % Variance is slightly inflated by outliers
Evaluation count : 35647680 in 60 samples of 594128 calls.
             Execution time mean : 1.695145 µs
    Execution time std-deviation : 20.186554 ns
   Execution time lower quantile : 1.670049 µs ( 2.5%)
   Execution time upper quantile : 1.740329 µs (97.5%)
                   Overhead used : 1.741068 ns

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 2 (3.3333 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] #_(assert (= (hash phm) (hash juhm))) (c/bench (unchecked-add (clojure.lang.Util/hasheq phm) (unchecked-add (clojure.lang.Util/hasheq "foo") (clojure.lang.Util/hasheq 123)))))
WARNING: Final GC required 1.028614538339401 % of runtime
Evaluation count : 1029948300 in 60 samples of 17165805 calls.
             Execution time mean : 56.797488 ns
    Execution time std-deviation : 0.732221 ns
   Execution time lower quantile : 55.856731 ns ( 2.5%)
   Execution time upper quantile : 58.469940 ns (97.5%)
                   Overhead used : 1.836671 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil

;;; patch applied

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] (assert (= (hash phm) (hash juhm))) (c/bench (clojure.lang.Util/hasheq phm)) (c/bench (clojure.lang.Util/hasheq juhm)))
Evaluation count : 5537698680 in 60 samples of 92294978 calls.
             Execution time mean : 8.973200 ns
    Execution time std-deviation : 0.157079 ns
   Execution time lower quantile : 8.733544 ns ( 2.5%)
   Execution time upper quantile : 9.289350 ns (97.5%)
                   Overhead used : 1.744772 ns
Evaluation count : 2481600 in 60 samples of 41360 calls.
             Execution time mean : 24.287800 µs
    Execution time std-deviation : 288.124326 ns
   Execution time lower quantile : 23.856445 µs ( 2.5%)
   Execution time upper quantile : 24.774097 µs (97.5%)
                   Overhead used : 1.744772 ns
nil

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] #_(assert (= (hash phm) (hash juhm))) (c/bench (unchecked-add (clojure.lang.Util/hasheq phm) (unchecked-add (clojure.lang.Util/hasheq "foo") (clojure.lang.Util/hasheq 123)))))
WARNING: Final GC required 1.298136122909759 % of runtime
Evaluation count : 954751500 in 60 samples of 15912525 calls.
             Execution time mean : 61.681794 ns
    Execution time std-deviation : 0.712110 ns
   Execution time lower quantile : 60.622003 ns ( 2.5%)
   Execution time upper quantile : 62.904801 ns (97.5%)
                   Overhead used : 1.744772 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil

As a side note, the earlier version of the patch available on the other branch doesn't have a separate branch for String. This made hasheq faster for objects implementing IHashEq, but slowed down the "three hashes" benchmark roughly by a factor of 2.

Comment by Alex Miller [ 12/May/14 11:39 PM ]

Just for clarity, please refer to patches attached here by name so as time goes on we don't have to correlate attachment time with comment time.

I'm not particularly worried about the cost of things that implement IHashEq as they should be unaffected other than potential inlining issues. I am curious about the cost of hasheq for objects that fall through to the end of the cases and pay the cost for all of the checks. The list farther up in the comments is a good place to start - things like Class, Character, and Var (which could possibly be addressed in Var).

Comment by Michał Marczyk [ 12/May/14 11:47 PM ]

Good point, I've edited the above comment to include the patch name.

Thanks for the benchmarking suggestions – I'll post some new results in ~6 minutes.

Comment by Michał Marczyk [ 13/May/14 12:18 AM ]

First, for completeness, here's a new patch (0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M-alternative.patch) which doesn't do the extra murmuring for types not otherwise handled. It's slower for the single PHM case; see below for details. Also, here's the branch on GitHub:

https://github.com/michalmarczyk/clojure/tree/alien-hasheq-3

As for the new results, the perf hit is quite large, I'm afraid:

;;; with patch (murmur hashCode for default version)
user=> (let [class-instance java.lang.String character-instance \a var-instance #'hash] (c/bench (clojure.lang.Util/hasheq class-instance)) (c/bench (clojure.lang.Util/hasheq character-instance)) (c/bench (clojure.lang.Util/hasheq var-instance)))
WARNING: Final GC required 1.409118084170768 % of runtime
Evaluation count : 655363680 in 60 samples of 10922728 calls.
             Execution time mean : 96.459888 ns
    Execution time std-deviation : 1.019817 ns
   Execution time lower quantile : 95.079086 ns ( 2.5%)
   Execution time upper quantile : 98.684168 ns (97.5%)
                   Overhead used : 1.708347 ns
Evaluation count : 675919140 in 60 samples of 11265319 calls.
             Execution time mean : 88.965959 ns
    Execution time std-deviation : 0.825226 ns
   Execution time lower quantile : 87.817159 ns ( 2.5%)
   Execution time upper quantile : 90.755688 ns (97.5%)
                   Overhead used : 1.708347 ns
Evaluation count : 574987680 in 60 samples of 9583128 calls.
             Execution time mean : 103.881498 ns
    Execution time std-deviation : 1.103615 ns
   Execution time lower quantile : 102.257474 ns ( 2.5%)
   Execution time upper quantile : 106.071144 ns (97.5%)
                   Overhead used : 1.708347 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil

;;; 1.6.0
user=> (let [class-instance java.lang.String character-instance \a var-instance #'hash] (c/bench (clojure.lang.Util/hasheq class-instance)) (c/bench (clojure.lang.Util/hasheq character-instance)) (c/bench (clojure.lang.Util/hasheq var-instance)))
WARNING: Final GC required 1.3353133083866688 % of runtime
Evaluation count : 1829305260 in 60 samples of 30488421 calls.
             Execution time mean : 34.205701 ns
    Execution time std-deviation : 0.379106 ns
   Execution time lower quantile : 33.680636 ns ( 2.5%)
   Execution time upper quantile : 34.990138 ns (97.5%)
                   Overhead used : 1.718257 ns

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 1 (1.6667 %)
	low-mild	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
Evaluation count : 1858100340 in 60 samples of 30968339 calls.
             Execution time mean : 30.401309 ns
    Execution time std-deviation : 0.213878 ns
   Execution time lower quantile : 30.095976 ns ( 2.5%)
   Execution time upper quantile : 30.871497 ns (97.5%)
                   Overhead used : 1.718257 ns
Evaluation count : 1592932200 in 60 samples of 26548870 calls.
             Execution time mean : 36.292934 ns
    Execution time std-deviation : 0.333512 ns
   Execution time lower quantile : 35.795063 ns ( 2.5%)
   Execution time upper quantile : 36.918183 ns (97.5%)
                   Overhead used : 1.718257 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil

One PHM and Class/Character/Var results with the new patch (no extra murmur step in the default case):

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] #_(assert (= (hash phm) (hash juhm))) (c/bench (unchecked-add (clojure.lang.Util/hasheq phm) (unchecked-add (clojure.lang.Util/hasheq "foo") (clojure.lang.Util/hasheq 123)))))
WARNING: Final GC required 1.258952964663877 % of runtime
Evaluation count : 1007768460 in 60 samples of 16796141 calls.
             Execution time mean : 58.195608 ns
    Execution time std-deviation : 0.482804 ns
   Execution time lower quantile : 57.655857 ns ( 2.5%)
   Execution time upper quantile : 59.154655 ns (97.5%)
                   Overhead used : 1.567532 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil
user=> (let [class-instance java.lang.String character-instance \a var-instance #'hash] (c/bench (clojure.lang.Util/hasheq class-instance)) (c/bench (clojure.lang.Util/hasheq character-instance)) (c/bench (clojure.lang.Util/hasheq var-instance)))
Evaluation count : 647944080 in 60 samples of 10799068 calls.
             Execution time mean : 91.275863 ns
    Execution time std-deviation : 0.659943 ns
   Execution time lower quantile : 90.330980 ns ( 2.5%)
   Execution time upper quantile : 92.711120 ns (97.5%)
                   Overhead used : 1.567532 ns
Evaluation count : 699506160 in 60 samples of 11658436 calls.
             Execution time mean : 84.564131 ns
    Execution time std-deviation : 0.517071 ns
   Execution time lower quantile : 83.765607 ns ( 2.5%)
   Execution time upper quantile : 85.569206 ns (97.5%)
                   Overhead used : 1.567532 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
Evaluation count : 594919980 in 60 samples of 9915333 calls.
             Execution time mean : 100.336792 ns
    Execution time std-deviation : 0.811312 ns
   Execution time lower quantile : 99.313490 ns ( 2.5%)
   Execution time upper quantile : 102.167675 ns (97.5%)
                   Overhead used : 1.567532 ns

Found 3 outliers in 60 samples (5.0000 %)
	low-severe	 3 (5.0000 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil
Comment by Michał Marczyk [ 13/May/14 1:05 AM ]

Here's a new patch (0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M-substring.patch) that takes the outrageous approach of replacing the Iterable/Map/Entry test with a .startsWith("java.util.") on the class name. (I experimented with .getClass().getPackage(), but the performance of that was terrible.) The branch is here:

https://github.com/michalmarczyk/clojure/tree/alien-hasheq-4

Hash perf on the "fall-through" cases with this patch seems to be very good:

user=> (let [class-instance java.lang.String character-instance \a var-instance #'hash] (c/bench (clojure.lang.Util/hasheq class-instance)) (c/bench (clojure.lang.Util/hasheq character-instance)) (c/bench (clojure.lang.Util/hasheq var-instance)))
WARNING: Final GC required 1.31690036780011 % of runtime
Evaluation count : 1661453640 in 60 samples of 27690894 calls.
             Execution time mean : 35.099750 ns
    Execution time std-deviation : 0.422800 ns
   Execution time lower quantile : 34.454839 ns ( 2.5%)
   Execution time upper quantile : 35.953584 ns (97.5%)
                   Overhead used : 1.556642 ns
Evaluation count : 1630167600 in 60 samples of 27169460 calls.
             Execution time mean : 35.487409 ns
    Execution time std-deviation : 0.309872 ns
   Execution time lower quantile : 35.083030 ns ( 2.5%)
   Execution time upper quantile : 36.190015 ns (97.5%)
                   Overhead used : 1.556642 ns

Found 4 outliers in 60 samples (6.6667 %)
	low-severe	 3 (5.0000 %)
	low-mild	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
Evaluation count : 1440434700 in 60 samples of 24007245 calls.
             Execution time mean : 40.894457 ns
    Execution time std-deviation : 0.529510 ns
   Execution time lower quantile : 40.055991 ns ( 2.5%)
   Execution time upper quantile : 41.990985 ns (97.5%)
                   Overhead used : 1.556642 ns
nil
Comment by Michał Marczyk [ 13/May/14 1:28 AM ]

The new patch (...-substring.patch) returns hashCode for java.util.** classes other than List, Map, Map.Entry and Set, of course, so no behaviour change there.

Here are the benchmarks for repeated PHM lookups (slightly slower than 1.6.0 apparently, though within 1 ns) and the "add three hasheqs" benchmark (66 ns with patch vs. 57 ns without):

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] (assert (= (hash phm) (hash juhm))) (c/bench (clojure.lang.Util/hasheq phm)) (c/bench (clojure.lang.Util/hasheq juhm)))
Evaluation count : 5183841240 in 60 samples of 86397354 calls.
             Execution time mean : 10.076893 ns
    Execution time std-deviation : 0.182592 ns
   Execution time lower quantile : 9.838456 ns ( 2.5%)
   Execution time upper quantile : 10.481086 ns (97.5%)
                   Overhead used : 1.565749 ns
Evaluation count : 3090420 in 60 samples of 51507 calls.
             Execution time mean : 19.596627 µs
    Execution time std-deviation : 224.380257 ns
   Execution time lower quantile : 19.288347 µs ( 2.5%)
   Execution time upper quantile : 20.085620 µs (97.5%)
                   Overhead used : 1.565749 ns
nil

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] #_(assert (= (hash phm) (hash juhm))) (c/bench (unchecked-add (clojure.lang.Util/hasheq phm) (unchecked-add (clojure.lang.Util/hasheq "foo") (clojure.lang.Util/hasheq 123)))))
WARNING: Final GC required 1.418253438197936 % of runtime
Evaluation count : 879210900 in 60 samples of 14653515 calls.
             Execution time mean : 66.939309 ns
    Execution time std-deviation : 0.747984 ns
   Execution time lower quantile : 65.667310 ns ( 2.5%)
   Execution time upper quantile : 68.155046 ns (97.5%)
                   Overhead used : 1.724002 ns
nil

It is important to note that I have obtained the no-patch result for the "three hasheqs" benchmarks on a fresh JVM when benchmarking 1.6.0, so that's also how I repeated the benchmark with the patch applied. Hashing many different types changes the results noticeably – presumably HotSpot backs off from some optimizations after seeing several different types passed in to hasheq?

Comment by Michał Marczyk [ 13/May/14 8:04 AM ]

Here's a new patch (0005-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch) that introduces a new isAlien static method that checks for instanceof Map/Map.Entry/Iterable and uses this method to test for "alien collection".

Initial benchmarking results are promising:

;;; "fall-through" benchmark
user=> (let [class-instance java.lang.String character-instance \a var-instance #'hash] (c/bench (clojure.lang.Util/hasheq class-instance)) (c/bench (clojure.lang.Util/hasheq character-instance)) (c/bench (clojure.lang.Util/hasheq var-instance)))
WARNING: Final GC required 1.258979068087473 % of runtime
Evaluation count : 1598432100 in 60 samples of 26640535 calls.
             Execution time mean : 36.358882 ns
    Execution time std-deviation : 0.566925 ns
   Execution time lower quantile : 35.718889 ns ( 2.5%)
   Execution time upper quantile : 37.414722 ns (97.5%)
                   Overhead used : 1.823120 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
Evaluation count : 1626362460 in 60 samples of 27106041 calls.
             Execution time mean : 35.426993 ns
    Execution time std-deviation : 0.294517 ns
   Execution time lower quantile : 35.047064 ns ( 2.5%)
   Execution time upper quantile : 36.058667 ns (97.5%)
                   Overhead used : 1.823120 ns

Found 1 outliers in 60 samples (1.6667 %)
	low-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
Evaluation count : 1461423180 in 60 samples of 24357053 calls.
             Execution time mean : 39.541873 ns
    Execution time std-deviation : 0.423707 ns
   Execution time lower quantile : 38.943560 ns ( 2.5%)
   Execution time upper quantile : 40.499433 ns (97.5%)
                   Overhead used : 1.823120 ns

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 2 (3.3333 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil

;;; "three hasheqs" benchmark
user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] #_(assert (= (hash phm) (hash juhm))) (c/bench (unchecked-add (clojure.lang.Util/hasheq phm) (unchecked-add (clojure.lang.Util/hasheq "foo") (clojure.lang.Util/hasheq 123)))))
WARNING: Final GC required 1.5536755331464491 % of runtime
Evaluation count : 820376460 in 60 samples of 13672941 calls.
             Execution time mean : 71.999365 ns
    Execution time std-deviation : 0.746588 ns
   Execution time lower quantile : 70.869739 ns ( 2.5%)
   Execution time upper quantile : 73.565908 ns (97.5%)
                   Overhead used : 1.738155 ns

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 2 (3.3333 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil
Comment by Michał Marczyk [ 13/May/14 8:28 AM ]

Ah, I left out the repeated phm hasheq lookup + hasheq of a java.util.HashMap instance pair of benchmarks from the above – here it is for completeness (no surprises though):

user=> (let [phm (apply hash-map (interleave (range 128) (range 128))) juhm (java.util.HashMap. phm)] (assert (= (hash phm) (hash juhm))) (c/bench (clojure.lang.Util/hasheq phm)) (c/bench (clojure.lang.Util/hasheq juhm)))
WARNING: Final GC required 1.260853406580491 % of runtime
Evaluation count : 5369135760 in 60 samples of 89485596 calls.
             Execution time mean : 10.380464 ns
    Execution time std-deviation : 3.407284 ns
   Execution time lower quantile : 9.510624 ns ( 2.5%)
   Execution time upper quantile : 11.461485 ns (97.5%)
                   Overhead used : 1.566301 ns

Found 5 outliers in 60 samples (8.3333 %)
	low-severe	 3 (5.0000 %)
	low-mild	 2 (3.3333 %)
 Variance from outliers : 96.4408 % Variance is severely inflated by outliers
Evaluation count : 3078180 in 60 samples of 51303 calls.
             Execution time mean : 19.717981 µs
    Execution time std-deviation : 209.896848 ns
   Execution time lower quantile : 19.401811 µs ( 2.5%)
   Execution time upper quantile : 20.180163 µs (97.5%)
                   Overhead used : 1.566301 ns

Found 2 outliers in 60 samples (3.3333 %)
	low-severe	 2 (3.3333 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil
Comment by Alex Miller [ 13/May/14 9:17 AM ]

Please don't submit any patches that change hashcode for anything other than making Java collections match Clojure collections - any other change is out of scope of this ticket.

In general, I would prefer just the execution time mean report for the moment rather than everything - the full criterium output makes these comments much harder to read and compare.

Comment by Alex Miller [ 13/May/14 9:33 AM ]

Could I get a summary of approaches, and a timing of 1.6.0 vs each patch for a consistent set of tests - say time of hash for Long, PHM, juHM, Class, and the "three hasheqs" test?

Comment by Rich Hickey [ 13/May/14 9:47 AM ]

"Hashing many different types changes the results noticeably – presumably HotSpot backs off from some optimizations after seeing several different types passed in to hasheq?"

Right - if your benchmarks do not treat this site as megamorphic you will get all sorts of distorted results.

Comment by Michał Marczyk [ 14/May/14 3:15 AM ]

Ok, I have what I think is an improved microbenchmark for this: xor of hasheqs for a long, a double, a string, a class, a character and a PHM (single instance, so it'll be a hash lookup). The results are not very encouraging.

Single form including the require to make it convenient to run; also bundled is a j.u.HashMap (128 entries) hasheq benchmark:

(do
  (require '[criterium.core :as c])
  (let [l    41235125123
        d    123.456
        s    "asdf;lkjh"
        k    BigInteger
        c    \S
        phm  (apply hash-map (interleave (range 128) (range 128)))
        juhm (java.util.HashMap. phm)
        f    (fn f []
               (-> (clojure.lang.Util/hasheq l)
                   (bit-xor (clojure.lang.Util/hasheq d))
                   (bit-xor (clojure.lang.Util/hasheq s))
                   (bit-xor (clojure.lang.Util/hasheq k))
                   (bit-xor (clojure.lang.Util/hasheq c))
                   (bit-xor (clojure.lang.Util/hasheq phm))))]
    (c/bench (f))
    (c/bench (hash juhm))))

Mean execution time as reported by Criterium:

version xor (ns) j.u.HM (µs)
unpatched 1.6.0 148.128748 1.701640
0005 patch 272.039667 21.201178
original patch 268.670316 21.169436
-alternative patch 271.747043 20.755397

The substring patch is broken (see below), so I skipped it. The patch I'm describing as the "original" one is attached as 0001-CLJ-1372-consistent-hasheq-for-java.util.-List-Map-M.patch.

Decisions common to all the patches:

1. One extra if statement in hasheq just above the default return with a three-way instanceof check.

2. The types tested for are j.u.Iterable, j.u.Map.Entry and j.u.Map.

3. Murmur3.hashOrdered takes Iterable, so that's why it's on the list. Map does not extend Iterable, so it's listed separately. Map.Entry is on the list, because ultimately the way to hash maps is to iterate over and hash their entries.

4. The actual hashing of the "alien" / host types is done by a separate static method – clojure.lang.Util.doalienhasheq – on the theory that this will permit hasheq to be inlined more aggressively and limit the worst of the perf hit to alien collections.

5. doalienhasheq checks for Map, Map.Entry, Set and List; entries are converted to lists for hashing, maps are hashed through entry sets and lists and sets are passed directly to Murmur3.

6. There is also a default case for other Iterable types – we must return hashCode or the result of composing some other function with hashCode for these, since we use equals to test them for equivalence.

The 0005 patch has hasheq call a separate private static method to perform the three-way type check, whereas the others put the check directly in the actual if test. The -alternative patch and the 0005 patch return hashCode in the default case, whereas the original patch composes Murmur3.hashInt with hashCode.

The substring patch only works for java.util.** classes and so doesn't solve the problem (it wouldn't correctly hash Guava collections, for example).

All of the patches change c.l.Util.hasheq and add one or two new static methods to clojure.lang.Util that act as helpers for hasheq. None of them changes anything else. Murmuring hashCode was a performance experiment that appeared to have a slight positive impact on some of the "fast cases" (in fact it's still the best performer among the current three patches in the microbenchmark presented above, although the margin of victory is of course extremely tiny). Thus I think all the current patches are in fact limited in scope to changes directly relevant to the ticket; the -alternative patch and the 0005 patch certainly are.

Comment by Michał Marczyk [ 14/May/14 3:29 AM ]

For completeness, branching on Map, Set etc. directly in hasheq, as with Jozef's original patch, results in the following timings in the microbenchmark introduced in my previous comment:

xor 315.866626 ns
juhm 18.520133 µs
Comment by Michał Marczyk [ 14/May/14 4:01 AM ]

New patch (0006) that leaves out the Map.Entry check; instead, two methods are introduced in the Murmur3 class to handle j.u.maps.

Java map entries aren't really integrated into Clojure – you can't use them like vectors, can't call seq on them etc. – so I don't think they need to match Clojure map entries in hasheq as long as j.u.maps do.

Timings:

xor 233.341689 ns
juhm 9.104637 µs
Comment by Michał Marczyk [ 14/May/14 4:17 AM ]

Checking for Map/Iterable in-line doesn't seem to affect xor benchmark results very much, but makes juhm hashing quicker. This is rather surprising to me. In any case, here's a new patch (0007) and the timings:

xor 233.062337 ns
juhm 8.629149 µs
Comment by Alex Miller [ 14/May/14 7:17 AM ]

What are equivalent timings without the patch?

Comment by Michał Marczyk [ 14/May/14 7:43 AM ]

They're listed in the table in the comment introducing the benchmark – 148.128748 ns for xor, 1.701640 µs for juhm.

Comment by Alex Miller [ 14/May/14 8:02 AM ]

What if we override hasheq for different types instead of using instanceof?

Comment by Michał Marczyk [ 14/May/14 12:50 PM ]

Overloaded methods are resolved statically, so there's no avoiding testing for type in the Object overload.

A more specific overload could be used to speed up hashing for its parameter type given a type hint or for literals, since the compiler would emit calls to that overload given appropriate compile-time information. There wouldn't be any speed-up in "implicit" hashing during hash map / set ops, however.

Comment by Daniel Compton [ 12/Nov/14 9:19 PM ]

This hit me when upgrading Factual/skuld from 1.5.1 to 1.6. clojure.data.fressian serialises c.l.PersistentHashSet sets into java.util.HashSet. This breaks equality checking in https://github.com/Factual/skuld/blob/b720feb142e6d274e85be208dc1d6d8634801719/test/skuld/net_test.clj#L8-L29 as we are comparing a set of maps where the original set contains a PersistentSet and the serialised and deserialised one contains a HashSet.

Comment by Daniel Compton [ 12/Nov/14 11:54 PM ]

This has come up again for me, details are in http://dev.clojure.org/jira/browse/DFRS-7

Comment by Max Penet [ 16/Mar/15 11:22 AM ]

This bit me again today as well (wasted a lot of time before figuring this one out). Any chance we'll have a patch for 1.7?

Comment by Alex Miller [ 16/Mar/15 12:18 PM ]

afaik, we are still in search of an approach with tolerable performance impacts before this can be considered.

Comment by Alex Miller [ 12/Jan/16 10:01 AM ]

While we are not opposed to addressing this ticket, we are not interested in addressing it at the expense of performance in comparisons that we care about more, and none of the current proposals meets that bar. For now, I am moving this to Backlog but would pull it out if a solution presents itself.





[CLJ-1467] Implement Comparable in PersistentList Created: 17/Jul/14  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Pascal Germroth Assignee: Unassigned
Resolution: Unresolved Votes: 8
Labels: collections

Attachments: Text File 0001-first-try-for-adding-compare.patch    

 Description   

PersistentVector implements Comparable already.



 Comments   
Comment by Bart Kastermans [ 13/Nov/14 11:17 AM ]

Patch for this issue; done with Jeroen van Dijk and Razvan Petruescu at a clojure meetup. Any feedback welcome; the learning for me here is not the fix, but learning how to deal with ant and jira etc.

Comment by Andy Fingerhut [ 13/Nov/14 12:31 PM ]

Looks like you have navigated the steps for creating a patch in the desired format, and attaching it to a JIRA ticket, just fine. I see your name on the list of contributors, which is a precondition before a patch can be committed to Clojure or a contrib library.

You've gotten past what are actually the easier parts. There is still the issue of whether this ticket is even considered by the Clojure core team to be an enhancement worth making a change to Clojure. Take a look at the JIRA workflow here if you haven't seen it already and are curious: http://dev.clojure.org/display/community/JIRA+workflow

If you like Pascal think that this is a change you really want to see in Clojure, you may vote on this or any other JIRA ticket (except ones you create yourself – the creator is effectively the 0th voter for a ticket). Log in and click on the Vote link near the top right, and/or Watch to get email updates of changes.

Comment by Bart Kastermans [ 14/Nov/14 3:12 AM ]

Andy, thanks for the info. I was not aware of the JIRA workflow.

Comment by Nicola Mometto [ 15/Jun/16 10:49 AM ]

It seems like other sequences besides PersistentLists should be comparable, one obvious example is `clojure.lang.APersistentVector$RSeq`. I stumbled upon it not being Comparable when trying to rewrite `(sort-by (juxt val key) m)` as `(sort-by rseq m)`





[CLJ-1458] Enhance the performance of map merges Created: 04/Jul/14  Updated: 28/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Yongqian Li Assignee: Unassigned
Resolution: Unresolved Votes: 8
Labels: performance

Attachments: Text File 0001-very-simple-test-of-the-merge-function.patch     Text File clj-1458-4.patch     Text File CLJ-1458-5.patch     Text File CLJ-1458-6.patch     Text File CLJ-1458-7.patch     Text File CLJ-1458-transient-merge2.patch     Text File CLJ-1458-transient-merge3.patch     Text File CLJ-1458-transient-merge.patch     Text File merge-test-2.patch     File transient-merge.diff    
Patch: Code and Test
Approval: Triaged

 Description   

It would be nice if merge used transients.

Patch

  • clj-1458-7.patch

Approach
Migrate c.c/merge later in core after transients & reduce. Leave older version as merge1 for use in cases the precede the newer definition. Make APersistentMap/conj & ATransientMap/cons aware of IKVReduce.

The attached patch preserves two existing behaviors of merge

  • metadata propagation
  • the right hand side of the merges can be a Map.Entry, an IPersistentVector where size=2, and regular maps.

Screened by:



 Comments   
Comment by Jason Wolfe [ 13/Sep/14 5:09 PM ]

I will take a crack at a patch today.

Comment by Jason Wolfe [ 13/Sep/14 5:42 PM ]

This patch (transient-merge.diff) makes merge, merge-with, and zipmap (since it was right there and could obviously benefit from transients as well) use transients.

Three potential issues:

  • I had to move the functions, since they depend on transient and friends. I assume this is preferable to a forward declaration. This was the best place I could find, but happy to move them elsewhere.
  • I added multiple arities, to avoid potential performance cost of transient-ing a single argument. Happy to undo this if desired.
  • I had to slightly alter the logic in merge-with, since transient maps don't support contains? (or find).
Comment by Michał Marczyk [ 14/Sep/14 12:43 PM ]

I posted a separate ticket for zipmap, with patch, on 30/May/12: CLJ-1005.

Comment by Jason Wolfe [ 14/Sep/14 5:28 PM ]

Ah, sorry if I overstepped then. Happy to remove that change from this patch then if that will simplify things – just let me know.

Comment by Ghadi Shayban [ 28/Dec/14 10:07 PM ]

alternate approach attached delaying merge until after protocols load, and then using transducers.

Comment by Michael Blume [ 28/Dec/14 11:50 PM ]

Looks like you're doing (get m k) twice – shouldn't that be thrown in a local?

Comment by Michael Blume [ 29/Dec/14 1:41 PM ]

um, put, in a local, I mean, 'throw' was a bad choice of word.

Comment by Ghadi Shayban [ 29/Dec/14 2:14 PM ]

Yeah there's that – won't be using get anyways after CLJ-700 gets committed.

We should add performance tests too. merging two maps, three, many maps, also varying the sizes of the maps, and for merge-with, varying the % of collisions.

Need to go back to the (some identity) logic, otherwise metadata is propagated from maps other than the first provided. I'll fix later.

Comment by Michael Blume [ 29/Dec/14 2:49 PM ]

I don't know if this is supposed to be allowed, but this breaks

(merge {} [:foo 'bar])

which is used in the wild by compojure-api

Comment by Michael Blume [ 29/Dec/14 2:49 PM ]

https://github.com/metosin/compojure-api/blob/0.16.6/src/compojure/api/meta.clj#L198

Comment by Michael Blume [ 29/Dec/14 2:54 PM ]

Ghadi, contains? uses get under the covers, so it's still two gets, right? It seems like it'd be more performant to stick with the ::none trick.

Comment by Nicola Mometto [ 29/Dec/14 5:36 PM ]

This calls for if-let + find.

Comment by Ghadi Shayban [ 29/Dec/14 10:37 PM ]

new patch addressing concerns so far

Comment by Ghadi Shayban [ 29/Dec/14 10:48 PM ]

CLJ-1458-transient-merge3.patch removes silly inlining macro, uses singleton fns instead.

Comment by Michael Blume [ 29/Dec/14 11:14 PM ]

Nice =)

This should come with tests. If we want to preserve the ability to merge with a MapEntry, we should test it. This isn't so much a weakness of the patch as of the existing tests. I see merge and merge-with being used a few times in the test suite, but I see no test whose purpose is to test their behavior.

Comment by Michael Blume [ 29/Dec/14 11:17 PM ]

Extremely simple merge test, we need more than this, but this is a start

Comment by Alex Miller [ 22/Jun/15 10:11 AM ]

clj-1458-4.patch refreshed to apply to master, no changes.

Comment by Ghadi Shayban [ 09/Jan/16 5:09 PM ]

I'd like to reevaluate the scope of this ticket. Can we address 'merge' only and defer 'merge-with'? It's by far the more common function. I've attached a new simplified patch.

Comment by Ghadi Shayban [ 09/Jan/16 9:50 PM ]

CLJ-1458-6.patch is yet another cleaner approach

Comment by Alex Miller [ 01/Feb/16 5:17 AM ]

Can you update the ticket approach section to discuss the APersistentMap.cons / ASSOC changes. Also, can you add a before / after perf test for one or more common cases?

Comment by Michael Blume [ 28/Sep/16 1:55 PM ]

Updated patch to handle use of merge in core_print before it's defined in core

Comment by Ghadi Shayban [ 28/Sep/16 2:22 PM ]

If anyone wants to take stewardship of this, go ahead. I had trouble getting consistent performance improvements on this. Obviously this needs fresh benchmarks.

Comment by Alex Miller [ 28/Sep/16 2:28 PM ]

Yes, this needs a benchmark showing demonstrable improvement. The whole goal here is improved perf - if we can't prove it's consistently faster, then there is no point in even reviewing it.

Comment by Ghadi Shayban [ 28/Nov/17 4:40 PM ]

This ticket needs help. Step 0 is writing a benchmark harness that exercises maps of various sizes, and the various polymorphic arguments below.

After a benchmark harness, implementation code needs to preserve this behavior:

  • If the first argument is not nil, its metadata propagates to the result.
  • The arguments can be a Map.Entry, an IPersistentVector where size=2, and regular maps.
  • When passed a non-map as the first argument, result is undefined.




[CLJ-1381] Improve support for extending protocols to primitive arrays Created: 13/Mar/14  Updated: 10/Nov/17

Status: Reopened
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5, Release 1.6
Fix Version/s: Release 1.10

Type: Enhancement Priority: Major
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 8
Labels: protocols

Approval: Vetted

 Description   

It is possible to extend protocols to primitive arrays but specifying the class for the type is a little tricky:

(defprotocol P (p [_]))
(extend-protocol P (Class/forName "[B") (p [_] "bytes"))
(p (byte-array 0))   ;; => "bytes"

However, things go bad if you try to do more than one of these:

(extend-protocol P 
  (Class/forName "[B") (p [_] "bytes")
  (Class/forName "[I") (p [_] "ints"))
CompilerException java.lang.UnsupportedOperationException: nth not supported on this type: Character, compiling:(NO_SOURCE_PATH:1:1)
	clojure.lang.Compiler.analyze (Compiler.java:6380)
	clojure.lang.Compiler.analyze (Compiler.java:6322)
	clojure.lang.Compiler$MapExpr.parse (Compiler.java:2879)
	clojure.lang.Compiler.analyze (Compiler.java:6369)
	clojure.lang.Compiler.analyze (Compiler.java:6322)
	clojure.lang.Compiler$InvokeExpr.parse (Compiler.java:3624)
	clojure.lang.Compiler.analyzeSeq (Compiler.java:6562)
	clojure.lang.Compiler.analyze (Compiler.java:6361)
	clojure.lang.Compiler.analyze (Compiler.java:6322)
	clojure.lang.Compiler$BodyExpr$Parser.parse (Compiler.java:5708)
	clojure.lang.Compiler$FnMethod.parse (Compiler.java:5139)
	clojure.lang.Compiler$FnExpr.parse (Compiler.java:3751)
Caused by:
UnsupportedOperationException nth not supported on this type: Character
	clojure.lang.RT.nthFrom (RT.java:857)
	clojure.lang.RT.nth (RT.java:807)
	clojure.core/emit-hinted-impl/hint--5951/fn--5953 (core_deftype.clj:758)
	clojure.core/map/fn--4207 (core.clj:2487)
	clojure.lang.LazySeq.sval (LazySeq.java:42)
	clojure.lang.LazySeq.seq (LazySeq.java:60)
	clojure.lang.RT.seq (RT.java:484)
	clojure.lang.RT.countFrom (RT.java:537)
	clojure.lang.RT.count (RT.java:530)
	clojure.lang.Cons.count (Cons.java:49)
	clojure.lang.Compiler.analyze (Compiler.java:6352)
	clojure.lang.Compiler.analyze (Compiler.java:6322)

The code in {parse-impls} is seeing the second {(Class/forName "[I")} as a function, not as a new type. One workaround for this is to only extend the protocol to one type at a time.

It would be even better (moving into enhancement area) if there was a syntax here to specify primitive array types - we already have the syntax of {bytes, ints, longs}, etc for type hints and those seem perfectly good to me.



 Comments   
Comment by Nahuel Greco [ 18/Sep/14 6:08 PM ]

It also breaks when extending only one array type:

(extend-protocol P
  String               (p [_] "string")
  (Class/forName "[B") (p [_] "ints") 
  )

;=> CompilerException java.lang.UnsupportedOperationException: nth not supported on this type ...

But changing the declaration order fixes it:

(extend-protocol P
  (Class/forName "[B") (p [_] "ints") 
  String               (p [_] "string")
  )

;=> OK
Comment by Alex Miller [ 12/Jan/16 3:16 PM ]

Dupe of CLJ-1790

Comment by Alex Miller [ 07/Jun/16 4:00 PM ]

On further inspection, I don't think this is a dupe of CLJ-1790 but merely a related problem.

Comment by Greg Chapman [ 18/Mar/17 11:04 AM ]

Using Class/forName has a further problem, as type-hints on the this parameter are longer emitted:

user=> (extend-protocol P (Class/forName "[B") (p [this] (aget this 0)))
Reflection warning, NO_SOURCE_PATH:2:50 - call to static method aget on clojure.lang.RT can't be resolved (argument types: unknown, int).

Reflection warnings are also generated for non-primitive arrays (so just supporting ints etc, won't completely fix this problem). It would be good to have a solution which covered all the problems with extending protocols to arrays.





[CLJ-2166] instrument exception doesn't contain function name in ex-data Created: 24/May/17  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: Release 1.10

Type: Enhancement Priority: Minor
Reporter: James Reeves Assignee: Unassigned
Resolution: Unresolved Votes: 8
Labels: spec

Attachments: Text File clj2166.patch    
Patch: Code
Approval: Screened

 Description   

When an instrumented function fails, it throws an IExceptionInfo. The ex-data of this exception contains the arguments that failed, but not the function that was called.

(require '[clojure.spec.alpha :as s] '[clojure.spec.test.alpha :as stest])
(defn foo [x] (+ x 1))
(s/fdef foo :args (s/cat :x number?))
(stest/instrument `foo)
(foo "x")  ;; ExceptionInfo Call to #'user/foo did not conform to spec:
(ex-data *e)

{:clojure.spec.alpha/problems
 [{:path [:args :x], :pred number?, :val "x", :via [], :in [0]}],
 :clojure.spec.alpha/args ("x"),
 :clojure.spec.alpha/failure :instrument,
 :clojure.spec.test.alpha/caller
 {:file "form-init1493151512736136730.clj",
  :line 101,
  :var-scope user/eval23284}}

*Proposed: Add an extra key clojure.spec.alpha/fn that has the symbol of the var under instrumentation.

After:

user> (ex-data *e)
=>
{:clojure.spec.alpha/problems [{:path [:args :x],
                                :pred clojure.core/number?,
                                :val "x",
                                :via [],
                                :in [0]}],
 :clojure.spec.alpha/spec #object[clojure.spec.alpha$regex_spec_impl$reify__1210
                                  0x4db4a004
                                  "clojure.spec.alpha$regex_spec_impl$reify__1210@4db4a004"],
 :clojure.spec.alpha/value ("x"),
 :clojure.spec.alpha/fn user/foo,
 :clojure.spec.alpha/args ("x"),
 :clojure.spec.alpha/failure :instrument,
 :clojure.spec.test.alpha/caller {:file "form-init2105027941758372775.clj",
                                  :line 1,
                                  :var-scope user/eval1050}}

Patch: clj2166.patch

Screened by: Alex Miller



 Comments   
Comment by Josh Jones [ 23/Jun/17 3:58 PM ]

I've done a small patch to add this, but is there a consensus on whether the value for the newly-added key should be the var itself (referenced by a :clojure.spec.alpha/var key), or the symbol (referenced by a :clojure.spec.alpha/fn key)?

Comment by Alex Miller [ 23/Jun/17 4:29 PM ]

Symbol

Comment by Josh Jones [ 23/Jun/17 6:22 PM ]

I've attached a one-liner patch, and welcome any comments or issues.

Note that although I signed the CA today (Rich also signed) and can thus officially submit, I am not yet on "Signed Contributor Agreement" list at https://clojure.org/community/contributors . I can't edit posts on Jira yet, which I why I did not edit to mark that a patch is present.

I've read the contrib guide but this is my first clojure patch, so please bear with me if I have made any errors in the workflow or otherwise here. Thanks!

Using the example in the original ticket, the new output of ex-data is:

user> (ex-data *e)
=>
{:clojure.spec.alpha/problems [{:path [:args :x],
                                :pred clojure.core/number?,
                                :val "x",
                                :via [],
                                :in [0]}],
 :clojure.spec.alpha/spec #object[clojure.spec.alpha$regex_spec_impl$reify__1210
                                  0x4db4a004
                                  "clojure.spec.alpha$regex_spec_impl$reify__1210@4db4a004"],
 :clojure.spec.alpha/value ("x"),
 :clojure.spec.alpha/fn user/foo,
 :clojure.spec.alpha/args ("x"),
 :clojure.spec.alpha/failure :instrument,
 :clojure.spec.test.alpha/caller {:file "form-init2105027941758372775.clj",
                                  :line 1,
                                  :var-scope user/eval1050}}
Comment by Alex Miller [ 24/Jun/17 7:29 AM ]

Thanks, looks good. I've also added the groups for you to have edit rights.





[CLJ-2124] Catch multiple exceptions in a single catch block Created: 12/Mar/17  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Daniel Compton Assignee: Unassigned
Resolution: Unresolved Votes: 8
Labels: exceptions, try-catch

Approval: Triaged

 Description   

Java 7 and up support multi-catch exceptions (http://www.oracle.com/technetwork/articles/java/java7exceptions-486908.html). It would be handy if Clojure also supported them to prevent catching something like Exception and then writing manual logic to check the Exception type, or duplicating the logic over multiple catch blocks.

A possible syntax for this could be:

(try (fn-that-throws)
     (catch (UnknownHostException NoRouteToHostException) e
       (go-offline)))

Prior art for this is a try* macro: https://gist.github.com/Gonzih/5814945.

One nuance to handle is

Edit: Note that in Java 7, you cannot both catch ExceptionA& ExceptionB in the same time, if ExceptionB is inherited(directly or indirectly) from ExceptionA. Compiler will complain: The exception ExceptionB is already caught by the alternative ExceptionA. - http://stackoverflow.com/a/3495968/826486

I tried searching to see if this had been asked already, but got mountains of results. I didn't see anything in the first few pages though.






[CLJ-1532] pr-str captures stdout from printing side-effects of lazily evaluated expressions. Created: 23/Sep/14  Updated: 14/Nov/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Defect Priority: Minor
Reporter: Silas Davis Assignee: Unassigned
Resolution: Unresolved Votes: 8
Labels: print
Environment:

Linux



 Description   

Because clojure.core/pr-str uses with-out-str to capture the output of pr (and pr cannot be parsed a writable thing - just uses out).

If you pr-str the result of something lazy you can get side-effects written to stdout with println interspersed with the output. For example in my case I was extracting benchmarks from the library criterium and trying to print the data structure to the file. The solution would be to provide an overload of pr/pr-str that takes a writer. I note that pr-on provides some of the functionality but it is private.

This is an ugly bug when you're trying to persist program output in EDN, because the randomly interspersed stdout messages make it invalid for read-string. We shouldn't need our functions to be pure for pr-str to work as expected.

I've omitted a patch because although I think a fix is straight-forward I'm not sure quite where it should go (e.g. make pr-on public, change pr, change pr-str)



 Comments   
Comment by Stuart Halloway [ 19/Jul/15 7:48 AM ]

as a workound for this, use print-dup or print-method





[CLJ-1322] doseq with several bindings causes "ClassFormatError: Invalid Method Code length" Created: 10/Jan/14  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: Release 1.10

Type: Defect Priority: Major
Reporter: Miikka Koskinen Assignee: Unassigned
Resolution: Unresolved Votes: 7
Labels: None
Environment:

Clojure 1.5.1, java 1.7.0_25, OpenJDK Runtime Environment (IcedTea 2.3.10) (7u25-2.3.10-1ubuntu0.12.04.2)


Attachments: Text File doseq-bench.txt     Text File doseq.patch     File script.clj    
Patch: Code
Approval: Incomplete

 Description   

Important Perf Note the new impl is faster for collections that are custom-reducible but not chunked, and is also faster for large numbers of bindings. The original implementation is hand tuned for chunked collections, and wins for larger chunked coll/smaller binding count scenarios, presumably due to the fn call/return tracking overhead of reduce. Details are in the comments.
Screened By
Patch doseq.patch

user=> (def a1 (range 10))
#'user/a1
user=> (doseq [x1 a1 x2 a1 x3 a1 x4 a1 x5 a1 x6 a1 x7 a1 x8 a1] (do))
CompilerException java.lang.ClassFormatError: Invalid method Code length 69883 in class file user$eval1032, compiling:(NO_SOURCE_PATH:2:1)

While this example is silly, it's a problem we've hit a couple of times. It's pretty surprising when you have just a couple of lines of code and suddenly you get the code length error.



 Comments   
Comment by Kevin Downey [ 18/Apr/14 12:20 AM ]

reproduces with jdk 1.8.0 and clojure 1.6

Comment by Nicola Mometto [ 22/Apr/14 5:35 PM ]

A potential fix for this is to make doseq generate intermediate fns like `for` does instead of expanding all the code directly.

Comment by Ghadi Shayban [ 25/Jun/14 8:39 PM ]

Existing doseq handles chunked-traversal internally, deciding the
mechanics of traversal for a seq. In addition to possibly conflating
concerns, this is causing a code explosion blowup when more bindings are
added, approx 240 bytes of bytecode per binding (without modifiers).

This approach redefs doseq later in core.clj, after protocol-based
reduce (and other modern conveniences like destructuring.)

It supports the existing :let, :while, and :when modifiers.

New is a stronger assertion that modifiers cannot come before binding
expressions. (Same semantics as let, i.e. left to right)

valid: [x coll :when (foo x)]
invalid: [:when (foo x) x coll]

This implementation does not suffer from the code explosion problem.
About 25 bytes of bytecode + 1 fn per binding.

Implementing this without destructuring was not a party, luckily reduce
is defined later in core.

Comment by Andy Fingerhut [ 26/Jun/14 12:25 AM ]

For anyone reviewing this patch, note that there are already many tests for correct functionality of doseq in file test/clojure/test_clojure/for.clj. It may not be immediately obvious, but every test for 'for' defined with deftest-both is a test for 'for' and also for 'doseq'.

Regarding the current implementation of doseq: it in't simply that it is too many bytes per binding, it is that the code size doubles with each additional binding. See these results, which measures size of the macroexpanded form rather than byte code size, but those two things should be fairly linearly related to each other here:

(defn formsize [form]
  (count (with-out-str (print (macroexpand form)))))

user=> (formsize '(doseq [x (range 10)] (print x)))
652
user=> (formsize '(doseq [x (range 10) y (range 10)] (print x y)))
1960
user=> (formsize '(doseq [x (range 10) y (range 10) z (range 10)] (print x y z)))
4584
user=> (formsize '(doseq [x (range 10) y (range 10) z (range 10) w (range 10)] (print x y z w)))
9947
user=> (formsize '(doseq [x (range 10) y (range 10) z (range 10) w (range 10) p (range 10)] (print x y z w p)))
20997

Here are results for the same expressions after Ghadi's patch doseq.patch dated June 25 2014:

user=> (formsize '(doseq [x (range 10)] (print x)))
93
user=> (formsize '(doseq [x (range 10) y (range 10)] (print x y)))
170
user=> (formsize '(doseq [x (range 10) y (range 10) z (range 10)] (print x y z)))
247
user=> (formsize '(doseq [x (range 10) y (range 10) z (range 10) w (range 10)] (print x y z w)))
324
user=> (formsize '(doseq [x (range 10) y (range 10) z (range 10) w (range 10) p (range 10)] (print x y z w p)))
401

It would be good to see some performance results with and without this patch, too.

Comment by Stuart Halloway [ 28/Jun/14 2:21 PM ]

In the tests below, the new impl is called "doseq2", vs. the original impl "doseq"

(def hund (into [] (range 100)))
(def ten (into [] (range 10)))
(def arr (int-array 100))
(def s "superduper")

;; big seq, few bindings: doseq2 LOSES
(dotimes [_ 5]
  (time (doseq [a (range 100000000)])))
;; 1.2 sec

(dotimes [_ 5]
  (time (doseq2 [a (range 100000000)])))
;; 1.8 sec

;; small unchunked reducible, few bindings: doseq2 wins
(dotimes [_ 5]
  (time (doseq [a s b s c s])))
;; 0.5 sec

(dotimes [_ 5]
  (time (doseq2 [a s b s c s])))
;; 0.2 sec

(dotimes [_ 5]
  (time (doseq [a arr b arr c arr])))
;; 40 msec

(dotimes [_ 5]
  (time (doseq2 [a arr b arr c arr])))
;; 8 msec

;; small chunked reducible, few bindings: doseq2 LOSES
(dotimes [_ 5]
  (time (doseq [a hund b hund c hund])))
;; 2 msec

(dotimes [_ 5]
  (time (doseq2 [a hund b hund c hund])))
;; 8 msec

;; more bindings: doseq2 wins bigger and bigger
(dotimes [_ 5]
  (time (doseq [a ten b ten c ten d ten ])))
;; 2 msec

(dotimes [_ 5]
  (time (doseq2 [a ten b ten c ten d ten ])))
;; 0.4 msec

(dotimes [_ 5]
  (time (doseq [a ten b ten c ten d ten e ten])))
;; 18 msec

(dotimes [_ 5]
  (time (doseq2 [a ten b ten c ten d ten e ten])))
;; 1 msec
Comment by Ghadi Shayban [ 28/Jun/14 6:23 PM ]

Hmm, I cannot reproduce your results.

I'm not sure whether you are testing with lein, on what platform, what jvm opts.

Can we test using this little harness instead directly against clojure.jar? I've attached a the harness and two runs of results (one w/ default heap, the other 3GB w/ G1GC)

I added a medium and small (range) too.

Anecdotally, I see doseq2 outperform in all cases except the small range. Using criterium shows a wider performance gap favoring doseq2.

I pasted the results side by side for easier viewing.

core/doseq                          doseq2
"Elapsed time: 1610.865146 msecs"   "Elapsed time: 2315.427573 msecs"
"Elapsed time: 2561.079069 msecs"   "Elapsed time: 2232.479584 msecs"
"Elapsed time: 2446.674237 msecs"   "Elapsed time: 2234.556301 msecs"
"Elapsed time: 2443.129809 msecs"   "Elapsed time: 2224.302855 msecs"
"Elapsed time: 2456.406103 msecs"   "Elapsed time: 2210.383112 msecs"

;; med range, few bindings:
core/doseq                          doseq2
"Elapsed time: 28.383197 msecs"     "Elapsed time: 31.676448 msecs"
"Elapsed time: 13.908323 msecs"     "Elapsed time: 11.136818 msecs"
"Elapsed time: 18.956345 msecs"     "Elapsed time: 11.137122 msecs"
"Elapsed time: 12.367901 msecs"     "Elapsed time: 11.049121 msecs"
"Elapsed time: 13.449006 msecs"     "Elapsed time: 11.141385 msecs"

;; small range, few bindings:
core/doseq                          doseq2
"Elapsed time: 0.386334 msecs"      "Elapsed time: 0.372388 msecs"
"Elapsed time: 0.10521 msecs"       "Elapsed time: 0.203328 msecs"
"Elapsed time: 0.083378 msecs"      "Elapsed time: 0.179116 msecs"
"Elapsed time: 0.097281 msecs"      "Elapsed time: 0.150563 msecs"
"Elapsed time: 0.095649 msecs"      "Elapsed time: 0.167609 msecs"

;; small unchunked reducible, few bindings:
core/doseq                          doseq2
"Elapsed time: 2.351466 msecs"      "Elapsed time: 2.749858 msecs"
"Elapsed time: 0.755616 msecs"      "Elapsed time: 0.80578 msecs"
"Elapsed time: 0.664072 msecs"      "Elapsed time: 0.661074 msecs"
"Elapsed time: 0.549186 msecs"      "Elapsed time: 0.712239 msecs"
"Elapsed time: 0.551442 msecs"      "Elapsed time: 0.518207 msecs"

core/doseq                          doseq2
"Elapsed time: 95.237101 msecs"     "Elapsed time: 55.3067 msecs"
"Elapsed time: 41.030972 msecs"     "Elapsed time: 30.817747 msecs"
"Elapsed time: 42.107288 msecs"     "Elapsed time: 19.535747 msecs"
"Elapsed time: 41.088291 msecs"     "Elapsed time: 4.099174 msecs"
"Elapsed time: 41.03616 msecs"      "Elapsed time: 4.084832 msecs"

;; small chunked reducible, few bindings:
core/doseq                          doseq2
"Elapsed time: 31.793603 msecs"     "Elapsed time: 40.082492 msecs"
"Elapsed time: 17.302798 msecs"     "Elapsed time: 28.286991 msecs"
"Elapsed time: 17.212189 msecs"     "Elapsed time: 14.897374 msecs"
"Elapsed time: 17.266534 msecs"     "Elapsed time: 10.248547 msecs"
"Elapsed time: 17.227381 msecs"     "Elapsed time: 10.022326 msecs"

;; more bindings:
core/doseq                          doseq2
"Elapsed time: 4.418727 msecs"      "Elapsed time: 2.685198 msecs"
"Elapsed time: 2.421063 msecs"      "Elapsed time: 2.384134 msecs"
"Elapsed time: 2.210393 msecs"      "Elapsed time: 2.341696 msecs"
"Elapsed time: 2.450744 msecs"      "Elapsed time: 2.339638 msecs"
"Elapsed time: 2.223919 msecs"      "Elapsed time: 2.372942 msecs"

core/doseq                          doseq2
"Elapsed time: 28.869393 msecs"     "Elapsed time: 2.997713 msecs"
"Elapsed time: 22.414038 msecs"     "Elapsed time: 1.807955 msecs"
"Elapsed time: 21.913959 msecs"     "Elapsed time: 1.870567 msecs"
"Elapsed time: 22.357315 msecs"     "Elapsed time: 1.904163 msecs"
"Elapsed time: 21.138915 msecs"     "Elapsed time: 1.694175 msecs"
Comment by Ghadi Shayban [ 28/Jun/14 6:47 PM ]

It's good that the benchmarks contain empty doseq bodies in order to isolate the overhead of traversal. However, that represents 0% of actual real-world code.

At least for the first benchmark (large chunked seq), adding in some tiny amount of work did not change results signifantly. Neither for (map str [a])

(range 10000000) =>  (map str [a])
core/doseq
"Elapsed time: 586.822389 msecs"
"Elapsed time: 563.640203 msecs"
"Elapsed time: 369.922975 msecs"
"Elapsed time: 366.164601 msecs"
"Elapsed time: 373.27327 msecs"
doseq2
"Elapsed time: 419.704021 msecs"
"Elapsed time: 371.065783 msecs"
"Elapsed time: 358.779231 msecs"
"Elapsed time: 363.874448 msecs"
"Elapsed time: 368.059586 msecs"

nor for intrisics like (inc a)

(range 10000000)
core/doseq
"Elapsed time: 317.091849 msecs"
"Elapsed time: 272.360988 msecs"
"Elapsed time: 215.501737 msecs"
"Elapsed time: 206.639181 msecs"
"Elapsed time: 206.883343 msecs"
doseq2
"Elapsed time: 241.475974 msecs"
"Elapsed time: 193.154832 msecs"
"Elapsed time: 198.757873 msecs"
"Elapsed time: 197.803042 msecs"
"Elapsed time: 200.603786 msecs"

I still see reduce-based doseq ahead of the original, except for small seqs

Comment by Ghadi Shayban [ 04/Aug/14 2:55 PM ]

A form like the following will not work with this patch:

(go (doseq [c chs] (>! c :foo)))

as the go macro doesn't traverse fn boundaries. The only such code I know is core.async/mapcat*, a private fn supporting a fn that is marked deprecated.

Comment by Ghadi Shayban [ 07/Aug/14 2:09 PM ]

I see #'clojure.core/run! was just added, which has a similar limitation

Comment by Rich Hickey [ 29/Aug/14 8:19 AM ]

Please consider Ghadi's feedback, esp re: closures.

Comment by Ghadi Shayban [ 22/Sep/14 4:36 PM ]

The current expansion of a doseq [1] under a go form is less than ideal due to the amount of control flow. 14 states in the state machine vs. 7 with loop/recur

[1] Comparison of macroexpansion of (go ... doseq) vs (go ... loop/recur)
https://gist.github.com/ghadishayban/639009900ce1933256a1

Comment by Nicola Mometto [ 25/Mar/15 6:07 PM ]

Related: CLJ-77

Comment by Nicola Mometto [ 03/Sep/15 12:59 PM ]

The general solution to this would be to automatically split methods when too large, using something like https://bitbucket.org/sperber/asm-method-size

Comment by Ghadi Shayban [ 24/Apr/16 12:25 AM ]

Example doseq impl and macroexpansion that does not suffer exponential bytecode growth. It also doesn't use any lambdas, so suitable for core.async.
https://gist.github.com/ghadishayban/fe84eb8db78f23be68e20addf467c4d4
It uses an explicit stack for the seqs/bindings.
It does not handle any chunking or modifiers yet.





[CLJ-1239] faster, more flexible dispatch for clojure.walk Created: 29/Jul/13  Updated: 14/Dec/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Stuart Sierra Assignee: Stuart Sierra
Resolution: Unresolved Votes: 7
Labels: walk

Attachments: Text File 0001-CLJ-1239-protocol-dispatch-for-clojure.walk.patch     Text File 0002-CLJ-1239-protocol-dispatch-for-clojure.walk.patch    
Patch: Code
Approval: Triaged

 Description   

The conditional dispatch in clojure.walk is slow and not open to extension. Prior to CLJ-1105 it did not support records.

Approach: Reimplement clojure.walk using protocols. The public API does not change. Users can extend the walk protocol to other types (for example, Java collections) if desired. As in CLJ-1105, this version of clojure.walk supports records.

Patch: 0002-CLJ-1239-protocol-dispatch-for-clojure.walk.patch

Performance: My tests indicate this is 1.5x-2x the speed of the original clojure.walk. See https://github.com/stuartsierra/clojure.walk2 for benchmarks.

Risks: This approach carries some risk of breaking user code that relied on type-specific behavior of the old clojure.walk. When running the full Clojure test suite, I discovered (and fixed) some breakages that did not show up in clojure.walk's unit tests. See, for example, commit 730eb75 in clojure.walk2



 Comments   
Comment by Vjeran Marcinko [ 19/Oct/13 12:32 PM ]

It looks, as it is now, that walking the tree and replacing forms doesn't preserve original meta-data contained in data structures.

Comment by Andy Fingerhut [ 23/Nov/13 1:11 AM ]

Patch 0001-CLJ-1239-protocol-dispatch-for-clojure.walk.patch no longer applies cleanly to latest Clojure master since the patch for CLJ-1105 was committed on Nov 22, 2013. From the description, it appears the intent was either that patch or this one, not both, so I am not sure what should happen with this patch, or even this ticket.

Comment by Alex Miller [ 23/Nov/13 1:52 AM ]

This patch and ticket are still candidates for future release.

Comment by Stuart Sierra [ 20/Dec/13 9:14 AM ]

Added new patch that applies on latest master after CLJ-1105.

Comment by Chouser [ 27/Feb/14 10:26 AM ]

The way this patch behaves can be surprising compared to regular maps:

(clojure.walk/prewalk-replace {[:a 1] nil} {:a 1, :b 2})
;=> {:b 2}

(defrecord Foo [a b])
(clojure.walk/prewalk-replace {[:a 1] nil} (map->Foo {:a 1, :b 2}))
;=> #user.Foo{:a 1, :b 2}

Note how the [:a 1] entry is removed from the map, but not from the record.

Here's an implementation that doesn't suffer from that problem, though it does scary class name munging instead: https://github.com/LonoCloud/synthread/blob/a315f861e04fd33ba5398adf6b5e75579d18ce4c/src/lonocloud/synthread/impl.clj#L66

Perhaps we could add to the defrecord abstraction to support well the kind of things that synthread code is doing clumsily, and then walk could take advantage of that.

Comment by Alex Miller [ 27/Feb/14 2:11 PM ]

@Chouser, can you file a new ticket related to this? It's hard to manage work on something from comments on a closed ticket.

Comment by Alex Miller [ 27/Feb/14 3:54 PM ]

@Chouser - Never mind! I was thinking this was the change that went into 1.6. Carry on.

Comment by Nicola Mometto [ 27/Feb/14 5:17 PM ]

Alex, for what it matters clojure-1.6.0 after CLJ-1105 exibits the same behaviour as described by Chouser for this patch





[CLJ-1941] Instrumentation of fns with primitive type hints fails Created: 01/Jun/16  Updated: 10/Nov/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: Release 1.10

Type: Defect Priority: Minor
Reporter: Kenny Williams Assignee: Unassigned
Resolution: Unresolved Votes: 7
Labels: spec
Environment:

Ubuntu 15.10
Using boot 2.6.0 on openjdk version "1.8.0_91"


Approval: Vetted

 Description   
(require '[clojure.spec :as s] '[clojure.spec.test :as st])
(defn foo [^double val] val)
(s/fdef foo :args (s/cat :val double?))
(st/instrument `foo)
(foo 5.2)

user=> (foo 5.2)
ClassCastException clojure.spec.test$spec_checking_fn$fn__13069 cannot be cast to clojure.lang.IFn$DO
       	user/eval6 (NO_SOURCE_FILE:5)
       	user/eval6 (NO_SOURCE_FILE:5)
       	clojure.lang.Compiler.eval (Compiler.java:6951)
       	clojure.lang.Compiler.eval (Compiler.java:6914)
       	clojure.core/eval (core.clj:3187)
       	clojure.core/eval (core.clj:3183)
       	clojure.main/repl/read-eval-print--9704/fn--9707 (main.clj:241)
       	clojure.main/repl/read-eval-print--9704 (main.clj:241)
       	clojure.main/repl/fn--9713 (main.clj:259)
       	clojure.main/repl (main.clj:259)
       	clojure.main/repl-opt (main.clj:323)
       	clojure.main/main (main.clj:422)

Cause: spec replaces var values with instrumented functions that will not work with primitive function interfaces

Approach: Take primitive interfaces into account and make them work, or document/fail that instrumentation will not work with these.



 Comments   
Comment by Kevin Downey [ 02/Jun/16 1:41 AM ]

spec replaces var values with instrumented functions, which works for the default linking case, var deref cast to ifn, invoke, but in the other cases (primitive functions, direct linking, others?) this won't work

Comment by Kenny Williams [ 02/Jun/16 3:39 PM ]

Hmm. Well this should be at least be documented. So, spec cannot be used on functions with a type hinted arg?

Comment by Sean Corfield [ 02/Jun/16 4:16 PM ]

Spec cannot be used on functions with primitive typed hinted arguments or returns – non-primitive type hints seem to be fine.

But documentation isn't enough here: instrumenting a namespace and then discovering it broke a function (that happened to have a primitive type hint) isn't acceptable. If the instrumentation isn't going to work, the function should be skipped (and a warning produced, hopefully).

Comment by Kevin Downey [ 02/Jun/16 8:10 PM ]

yeah, I was giving the root cause of the issue, not excusing the issue.

Understanding the root cause predicts other places where there will be issues: where ever some non-default function linking strategy is used.

One such place is direct linked functions, but I suspect for direct linked functions, Clojure/Core will just say you should only instrument code for testing, and you should only turn on direct liking for production.

Another case, which I am sort of surprised we haven't heard more about yet is protocol functions.

Comment by Sean Corfield [ 02/Jun/16 8:35 PM ]

Your comment about direct linking made me wonder about the validity of spec'ing and instrumenting clojure.core functions. The examples show clojure.core/symbol, but Clojure's core library is shipped as direct linked, as of 1.8.0 isn't it?

Comment by Kevin Downey [ 03/Jun/16 3:14 AM ]

what alters the calling convention isn't the function being compiled with direct linking on, but a caller of that function being compiled with direct linking on.

This code will throw a non-conforming error for the bogus symbol spec with direct linking off, and return the symbol foo with direct linking on

(require '[clojure.spec :as s])

(s/fdef symbol
  :args string?
  :ret symbol?)

(defn foo
  []
  (symbol 'foo))

(s/instrument-all)

(foo)
Comment by Kevin Downey [ 03/Jun/16 3:26 AM ]

This code returns true because m is a protocol function, if you replace it with a regular function it throws a non-conforming error

(require '[clojure.spec :as s])

(defprotocol P
  (m [_]))

(deftype T []
  P
  (m [_] true))

(s/fdef m
  :args (s/cat :p (constantly false))
  :ret string?)

(defn foo
  []
  (m (T.)))

(s/instrument-all)

(foo)
Comment by Alex Miller [ 13/Jun/16 3:53 PM ]

@Sean instrumenting core functions will work for calls from your code into core (which are presumably not direct-linked), but will not affect calls from one core function to another as they are direct-linked and do not go through the var. One thing we've considered for a long while is building a dev version of core that would not be direct-linked and could potentially turn on instrumentation or other helpful dev-time tooling.

Comment by Sean Corfield [ 14/Jun/16 5:48 PM ]

Thanks for that answer @alexmiller – We have dev set to non-direct-linking but QA / production set to direct linking, so I'm only concerned about possible issues in dev with (s/instrumental-all) and wanting to be sure "code won't break". If instrumentation won't affect existing (direct-linked) calls within core, that's good enough for me. I am concerned about primitive hinting and protocols (and whatever crawls out of the woodwork here) since you don't want to be forced to read the source of every library you include, just to see whether (s/instrument-all) is safe or whether it will bite you in some weird way while you're developing.





[CLJ-1201] There should also be writing in clojure.edn Created: 15/Apr/13  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Vitaly Shukela Assignee: Unassigned
Resolution: Unresolved Votes: 7
Labels: edn


 Description   

In clojure.edn I see only "read" and "read-string".

For symmetry I expect "write" and "write-string" to be nearby. At first it could be just alias for "pr" and "pr-str", but in furure they may limited version of "pr" which only produces valid input for clojure.edn/read.



 Comments   
Comment by Andy Fingerhut [ 23/May/13 5:56 PM ]

Related clojure-dev message: https://groups.google.com/forum/?fromgroups#!topic/clojure-dev/fLJWh9A3OuA

and enhancement proposal wiki page: http://dev.clojure.org/pages/viewpage.action?pageId=8192126





[CLJ-1103] Make conj assoc dissoc and transient versions handle args similarly Created: 04/Nov/12  Updated: 09/Oct/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.4, Release 1.5, Release 1.6
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Andy Fingerhut Assignee: Alex Miller
Resolution: Unresolved Votes: 7
Labels: collections, transient

Attachments: Text File clj-1103-10.patch     File clj-1103-7.diff     Text File clj-1103-8.patch     Text File clj-1103-9.patch    
Approval: Triaged

 Description   

Examples that work as expected:

Clojure 1.7.0-master-SNAPSHOT
user=> (dissoc {})
{}
user=> (disj #{})
#{}
user=> (conj {})
{}
user=> (conj [])
[]

Examples that do not work as desired, but are changed by the proposed patch:

user=> (assoc {})
ArityException Wrong number of args (1) passed to: core/assoc  clojure.lang.AFn.throwArity (AFn.java:429)
user=> (assoc! (transient {}))
ArityException Wrong number of args (1) passed to: core/assoc!  clojure.lang.AFn.throwArity (AFn.java:429)
user=> (dissoc! (transient {}))
ArityException Wrong number of args (1) passed to: core/dissoc!  clojure.lang.AFn.throwArity (AFn.java:429)

I looked through the rest of the code for similar cases, and found that there were some other differences between them in how different numbers of arguments were handled, such as:

+ conj handles an arbitrary number of arguments, but conj! does not.
+ assoc checks for a final key with no value specified (CLJ-1052), but assoc! did not.

History/discussion: A discussion came up in the Clojure Google group about conj giving an error when taking only a coll as an argument, as opposed to disj which works for this case:

https://groups.google.com/forum/?fromgroups=#!topic/clojure/Z9mFxsTYTqQ

Screened by: Alex Miller



 Comments   
Comment by Andy Fingerhut [ 04/Nov/12 6:04 PM ]

clj-1103-make-conj-assoc-dissoc-handle-args-similarly-v1.txt dated Nov 4 2012 makes conj conj! assoc assoc! dissoc dissoc! handle args similarly to each other.

Comment by Brandon Bloom [ 09/Dec/12 5:30 PM ]

I too ran into this and started an additional discussion here: https://groups.google.com/d/topic/clojure-dev/wL5hllfhw4M/discussion

In particular, I don't buy the argument that (into coll xs) is sufficient, since into implies conj and there isn't an terse and idiomatic way to write (into map (parition 2 keyvals))

So +1 from me

Comment by Andy Fingerhut [ 08/Nov/13 10:41 AM ]

Patch clj-1103-2.diff is identical to the previous patch clj-1103-make-conj-assoc-dissoc-handle-args-similarly-v1.txt except it applies cleanly to latest master. The only changes were some changed context lines in a test file.

Comment by Andy Fingerhut [ 23/Nov/13 12:52 AM ]

Patch clj-1103-3.diff is identical to the patch clj-1103-2.diff, except it applies cleanly to latest master. The only changes were some doc strings for assoc! and dissoc! in the context lines of the patch.

Comment by Andy Fingerhut [ 14/Feb/14 12:04 PM ]

Patch clj-1103-4.diff is identical to the previous clj-1103-3.diff, except it updates some context lines so that it applies cleanly to latest Clojure master as of today.

Comment by Alex Miller [ 05/Jun/14 9:29 PM ]

Can someone update the description with some code examples? Or drop them here at least?

Comment by Brandon Bloom [ 05/Jun/14 9:35 PM ]

What do you mean code examples?

These currently work as expected:
(dissoc {})
(disj #{})

The following fail with arity errors:
(assoc {})
(conj {})

Similarly for the transient ! versions.

This is annoying if you ever try to do (apply assoc m keyvals)... it works at first glance, but then one day, bamn! Runtime error because you tried to give it an empty sequence of keyvals.

Comment by Andy Fingerhut [ 06/Aug/14 5:05 PM ]

Patch clj-1103-5.diff dated Aug 6 2014 applies cleanly to latest Clojure master as of today, whereas the previous patch did not. Rich added 1-arg version of conj to 1.7.0-alpha1, so that change no longer is part of this patch.

Comment by Andy Fingerhut [ 29/Aug/14 6:04 PM ]

Patch clj-1103-6.diff dated Aug 29 2014 is identical to the former patch clj-1103-5.diff (which will be deleted), except it applies cleanly to the latest Clojure master.

Comment by Andy Fingerhut [ 26/May/15 9:00 PM ]

Patch clj-1103-7.diff dated May 25 2015 is identical to the former patch clj-1103-6.diff (which will be deleted), except it applies cleanly to the latest Clojure master.

Comment by Michael Blume [ 12/Oct/15 5:32 PM ]

Updated patch to apply cleanly to master

Comment by Michael Blume [ 06/Oct/17 4:16 PM ]

Updated patch

Comment by Andy Fingerhut [ 06/Oct/17 6:00 PM ]

Is it intentional that clj-1103-9.patch leaves out the changes to assoc! that were in the earlier patches? I can create another updated one if so – just curious if there was a reason for the change.

Comment by Michael Blume [ 06/Oct/17 7:17 PM ]

That was not intentional at all, thanks for catching it, I'm honestly not sure what happened on my end to make that happen. I think this patch should be a correct update. Sorry about that.

Comment by Andy Fingerhut [ 09/Oct/17 10:17 PM ]

No worries, and I thank you for keeping the patch current, even while keeping my name on it.





[CLJ-1209] clojure.test does not print ex-info in error reports Created: 11/May/13  Updated: 22/Dec/16

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Critical
Reporter: Thomas Heller Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: clojure.test

Attachments: Text File 0001-use-new-printing-method.patch     Text File 0002-CLJ-1209-show-ex-data-in-clojure-test.patch     File clj-test-print-ex-data.diff     Text File output-with-0002-patch.txt    
Patch: Code
Approval: Triaged

 Description   

clojure.test does not print the data attached to ExceptionInfo in error reports.

(use 'clojure.test)
(deftest ex-test (throw (ex-info "err" {:some :data})))
(ex-test)

ERROR in (ex-test) (core.clj:4591)
Uncaught exception, not in assertion.
expected: nil
  actual: clojure.lang.ExceptionInfo: err
 at clojure.core$ex_info.invoke (core.clj:4591)
    user/fn (NO_SOURCE_FILE:2)
    clojure.test$test_var$fn__7666.invoke (test.clj:704)
    clojure.test$test_var.invoke (test.clj:704)
    ...

Approach: In clojure.stacktrace, which clojure.test uses for printing exceptions, add a check for ex-data and pr it.

After:

ERROR in (ex-test) (core.clj:4591)
Uncaught exception, not in assertion.
expected: nil
  actual: clojure.lang.ExceptionInfo: err
{:some :data}
 at clojure.core$ex_info.invoke (core.clj:4591)
    user/fn (NO_SOURCE_FILE:3)
    clojure.test$test_var$fn__7667.invoke (test.clj:704)
    clojure.test$test_var.invoke (test.clj:704)

Patch: 0002-CLJ-1209-show-ex-data-in-clojure-test.patch



 Comments   
Comment by Alex Miller [ 20/Dec/13 9:53 AM ]

Great idea, thx for the patch!

Comment by Alex Miller [ 20/Dec/13 9:54 AM ]

Would be great to see a before and after example of the output.

Comment by Ivan Kozik [ 12/Jul/14 10:35 PM ]

Attaching sample output

Comment by Stuart Sierra [ 05/Sep/14 3:24 PM ]

As pointed out on IRC, there's a possible risk of trying to print an infinite lazy sequence that happened to be included in ex-data.

To mitigate, consider binding *print-length* and *print-level* to small numbers around the call to pr.

Comment by Stephen C. Gilardi [ 13/May/15 2:39 PM ]

http://dev.clojure.org/jira/browse/CLJ-1716 may cover this well enough that this issue can be closed.

Comment by Alex Miller [ 14/May/15 8:35 AM ]

I don't think 1716 covers it at all as clojure.test/clojure.stacktrace don't use the new throwable printing. But they could! And that might be a better solution than the patch here.

For example, the existing patch does not consider what to do about nested exceptions, some of which might have ex-data. The new printer handles all that in a consistent way.

Comment by Ed Bowler [ 22/Dec/16 11:35 AM ]

I think http://dev.clojure.org/jira/secure/attachment/16361/0001-use-new-printing-method.patch fixes the printing of the Exceptions.





[CLJ-2115] Support data conveying conform errors (alternative/complement to :clojure.spec/invalid) Created: 22/Feb/17  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.9
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Max Penet Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: spec


 Description   

At the moment if a conform calls fails (returning :clojure.spec/invalid) there is no way to supply extra information about why it failed. We do have the possibility to get explain-data, but at best this would return a spec form, the original value and some metadata.

While this is fine in most cases, some conformer functions upon failure can provide extra data that'd be useful to the consumer. A practical example we had was a spec that can contain values for a String based DSL (think SQL like), that would conform these values to their parsed AST. When the conform wrapped function fails it would throw an ex-info with line/col info and more metadata about the failure. But all this data was lost since we can only return :clojure.spec/invalid. All this happened inside a rule engine schema, that can contain hundreds of these; re-parsing all the failing values for error reporting is something we wanted to avoid.

The proposal would be to to support a new return value that'd allow conveying data about the conform failure, or to support both this new value and :clojure.spec/invalid.
This could take the form of (explain-info {..}) potentially returned by conformer function for later consumption by explain, to match clojure semantics with exceptions (ex-info/ex-data, explain-info/explain-data).

A more naive implementation could just allow to throw inside the conformer function and have the error merged/assoced into the explain map (but that might be a bit too invasive in my opinion).






[CLJ-1807] Add prefer-proto, like prefer-method but for protocols Created: 30/Aug/15  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.8
Fix Version/s: None

Type: Feature Priority: Major
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: protocols

Attachments: Text File 0001-CLJ-1807-add-prefer-proto.patch    
Approval: Triaged

 Description   

Currently it's possible to extend a protocol to multiple interfaces but there's no mechanism like prefer-method for multimethods to prefer one implementation over another, as a result, if multiple interfaces match, a random one is picked.

One particular example where this is a problem, is trying to handle generically records and maps (this come up in tools.analyzer): when extending a protocol to both IRecord and IPersistentMap there's no way to make the IRecord implementation be chosen over the IPersistentMap one and thus protocols can't be used.

The attached patch adds a prefer-proto function that's like prefer-method but for protocols.

No performance penalty is paid if prefer-proto is never used, if it's used there will be a penalty during the first protocol method dispatch to lookup the perference table but the protocol method cache will remove that penalty for further calls.

Example:

user=> (defprotocol p (f [_]))
p
user=> (extend-protocol p clojure.lang.Counted (f [_] 1) clojure.lang.IObj (f [_] 2))
nil
user=> (f [1])
2
user=> (prefer-proto p clojure.lang.Counted clojure.lang.IObj)
nil
user=> (f [1])
1

Patch: 0001-CLJ-1807-add-prefer-proto.patch






[CLJ-735] Improve error message when a protocol method is not found Created: 04/Feb/11  Updated: 04/May/15

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.2
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: errormsgs

Attachments: File protocolerr.diff    
Patch: Code
Approval: Triaged

 Description   

If you call a protocol function but pass the wrong arity (forget an argument for example), you currently a message that says "No single method ... of interface ... found for function ... of protocol ...". The code in question is getting matching methods from the Reflector and creates this message if the number of matches != 1.

There are really two cases there:

  • matches == 0 - this happens frequently due to typos
  • matches > 1 - this presumably happens infrequently

I propose that the == 0 case instead should have slightly different text at the beginning and a hint as to the intended arity within it:

"No method: ... of interface ... with arity ... found for function ... of protocol ...".

The >1 case should have similar changes: "Multiple methods: ... of interface ... with arity ... found for function ... of protocol ...".

Patch is attached. I used case which presumably should have better performance than a nested if/else. I was not sure whether the reported arity should match the actual Java method arity or Clojure protocol function arity (including the target). I did the former.

I did not add a test as I wasn't sure whether checking error messages in tests was appropriate or not. Happy to add that if requested.



 Comments   
Comment by Chas Emerick [ 14/Jul/11 6:39 AM ]

I was not sure whether the reported arity should match the actual Java method arity or Clojure protocol function arity (including the target). I did the former.

I think it should be the latter. The message is emitted when the protocol methods are being invoked through the corresponding function, so it should be consistent with the errors emitted by regular functions.

+1 for some tests, too. There certainly are tests for reflection warnings and such.

FWIW, I'm happy to take this on if Alex is otherwise occupied.

Comment by Alex Miller [ 04/May/15 4:22 PM ]

Picking this up a zillion years later ...

1) I think I would now change the control flow slightly to make the normal path (methods.size() == 1) first and the error cases after that without that switch/case stuff:

if(methods.size() == 1) { 
  this.onMethod = (java.lang.reflect.Method) methods.get(0);
} else if(methods.size() == 0) {
  ...
} else {
  ...
}

2) The Compiler code should use tabs instead of spaces.

3) I would like tests added for the error messages in these two cases. Those can go in clojure.test-clojure.protocols.





[CLJ-1906] Clojure should make representing iterated api calls easier Created: 30/Mar/16  Updated: 15/Sep/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Kevin Downey Assignee: Ghadi Shayban
Resolution: Unresolved Votes: 6
Labels: None

Attachments: Text File 0001-CLJ-1906-add-ingeminate-function.patch     Text File 0001-CLJ-1906-add-unfold-function.patch     Text File 0001-CLJ-1906-transducer-enabled-iterate.patch     File CLJ-1906-seqable-reducible.diff     Text File CLJ-1906-successions.patch    

 Description   

Many apis (elasticsearch, github, s3, etc) have parts of the api
which, in usage, end up being used in an interative way. You make an
api call, and you use the result to make another api call, and so
on. This most often shows up in apis have some concept of pages of
results that you page through, and is very prevalent in http apis.

This appears to be such a common pattern that it would be great if
Clojure had in built support for it.

You may think Clojure already does have support for it, after all,
Clojure has `iterate`. In fact the docstring for `iterate`
specifically says the function you give it must be free of side
effects.

I propose adding a function `unfold` to clojure.core to support this
use case. `unfold` would return an implementation of ReduceInit. The
name `unfold` matches what would be a similar Haskell function
(https://hackage.haskell.org/package/base-4.8.2.0/docs/Data-List.html#v:unfoldr)
and also matches the name for a similar function used in some existing
Clojure libraries
(https://github.com/amalloy/useful/blob/develop/src/flatland/useful/seq.clj#L128-L147).

`unfold` in some ways looks like a combination of `take-while` and
`iterate`, except for the fact that `iterate` requires a pure
function. Another possible solution would be a version of `iterate`
that doesn't require a pure function.

It seems like given the use case I envision for `unfold`, a
non-caching reducible would be perfect. But that would leave those
that prefer seqs high and dry, so maybe at least some consideration
should be given to seqs.

Mailing list discussion is here
(https://groups.google.com/forum/#!topic/clojure-dev/89RNvkLdYc4)

A sort of dummy api you might want to interact with would look something like

(import '(java.util UUID))

(def uuids (repeatedly 1000 #(UUID/randomUUID)))

(def uuid-index
  (loop [uuids uuids
         index  {}]
    (if (seq uuids)
      (recur (rest uuids) (assoc index (first uuids) (rest uuids)))
      index)))

(defn api
  "pages through uuids, 10 at a time. a list-from of :start starts the listing"
  [list-from]
  (let [page (take 10 (if (= :start list-from)
                        uuids
                        (get uuid-index list-from)))]
    {:page page
     :next (last page)}))

given the above api, if you had an implementation of `unfold` that took a predicate that decided when to continue unfolding, a producer which given a value in a sequence produced the next value, and an initial value, you could do something like this:

(= uuids (into [] (mapcat :page) (unfold :next (comp api :next) (api :start))))

and the result would be true.

The equivilant take-while + iterate would be something like:

;; the halting condition is not strictly the same
(= uuids (into [] (mapcat :page) (take-while (comp seq :page) (iterate (comp api :next) (api :start)))))


 Comments   
Comment by Kevin Downey [ 31/Mar/16 4:21 PM ]

I made two patches, one adds unfold as discussed above, one adds ingeminate which is like iterate but without the function purity restrictions, and doesn't return a seq.

Comment by Ghadi Shayban [ 11/Apr/16 10:46 AM ]

Though syntax is less important than the semantics, may I propose the name `progression` for this? Clojure's fold is called reduce, so unfold is too much like Haskell. Other names I was considering include evolve & derivations.

Comment by Alex Miller [ 11/Apr/16 11:23 AM ]

Another option would be `productions` (reminiscent of `reductions`).

Comment by Kevin Downey [ 11/Apr/16 9:32 PM ]

productions has a nice ring to it. emanate could work too, would sort near eduction

Comment by Ghadi Shayban [ 12/Apr/16 10:08 PM ]

Adding a patch with a generator impl that is clojure.lang.{Seqable,IReduceInit}.

Generative tests assert that the seq and reduce halves are equivalent.

Tests assert basic functionality, obeying reduced, and maximal laziness of the seq impl.

Docstring has been wordsmithed and the function named `productions`.

Comment by Kevin Downey [ 18/Apr/16 3:21 PM ]

apparently unfold is part of SRFI 1: List Library in scheme land http://srfi.schemers.org/srfi-1/srfi-1.html#FoldUnfoldMap

it looks like their unfold is take-while + iterate + map

Comment by Ghadi Shayban [ 23/Apr/16 11:06 PM ]

Main differences between Scheme's impl and this proposed one:
Predicate reversed (stop? vs continue?)
Scheme has a "mapping function" to produce a different value from the current seed, Clojure doesn't (but has transducers)
Scheme has an extra optional arg to build the tail of the list

Now I'm partial to the name successions.

Comment by Michał Marczyk [ 10/May/16 11:07 AM ]

I can confirm that I found unfold quite useful in my Scheme days.

In Clojure, this general pattern can be expressed using transducers at a modest cost in keystrokes:

(def numbers (doall (range 1000)))

(defn api [list-from]
  (if list-from
    (let [page (vec
                 (take 10 (if (= :start list-from)
                            numbers
                            (drop list-from numbers))))]
      {:page page
       :next (some-> (last page) inc)})))

(= numbers
   (sequence (comp (take-while some?)
                   (mapcat :page))
             (iterate (comp api :next)
                      (api :start))))
;= true

Maybe this could be simplified with an xform-enabled version of iterate?

(defn iterate*
  ([f seed]
   (iterate f seed))
  ([xform f seed]
   (sequence xform (iterate f seed))))

(= numbers
   (iterate*
     (comp (take-while some?) (mapcat :page))
     (comp api :next)
     (api :start)))
;= true

Admittedly this takes more characters, but is quite generic and a transducer-enabled overload in iterate feels pretty natural to me. Attaching a simple patch implementing this in clojure.core/iterate – I'll look at clojure.lang.Iterate to see if it's worth implementing direct support later, unless of course nobody wants this.

Comment by Michał Marczyk [ 10/May/16 11:08 AM ]

0001-CLJ-1906-transducer-enabled-iterate.patch adds a ternary overload to iterate that delegates to the binary overload and sequence.

Comment by Ghadi Shayban [ 10/May/16 12:56 PM ]

A few unsatisfactory things about overloading {iterate}
1) iterate's docstring says {f must be free of side-effects}
2) There is boilerplate and subtlety around the terminating item. In this case the final API call is made unconditionally, leading to an extra empty/marker item that is filtered by take-while. With the current proposal, the predicate controls iteration from the inside out

Comment by Ghadi Shayban [ 06/Jun/16 8:40 AM ]

updated patch to apply cleanly to core

Comment by Ghadi Shayban [ 18/Sep/16 11:40 PM ]

I'm not sure I'm sold on this anymore, and have suggested a different approach on the mailing list https://groups.google.com/d/msg/clojure-dev/89RNvkLdYc4/PAJh8gfmDAAJ

Comment by Ghadi Shayban [ 17/Apr/17 1:40 PM ]

I have been marinating upon two generator functions that cover use-cases including the one listed above.

One of them is similar to Scheme's unfold but with some deviations more appropriate to Clojure. The other function takes a side-effecting producer and a sentinel value.

Ignore the naming and examine the semantics. https://gist.github.com/ghadishayban/902373e247e920855139902912d237f0





[CLJ-1117] partition docstring should be more explicit about dropped or partial trailing elements Created: 29/Nov/12  Updated: 06/Sep/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6
Fix Version/s: None

Type: Enhancement Priority: Minor
Reporter: Timothy Baldridge Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: docstring
Environment:

OS X, 10.8


Attachments: Text File clj-1117.patch    
Patch: Code
Approval: Triaged

 Description   

The doc for partition states "In case there are not enough padding elements, return a partition with less than n items." However, the behavior of this function is as follows:

user=> (partition 3 (range 10))
((0 1 2) (3 4 5) (6 7 8))
user=> (partition 4 (range 10))
((0 1 2 3) (4 5 6 7))

Proposed: Proposed docstring update in bold:

Returns a lazy sequence of lists of n items each, at offsets step
apart. If step is not supplied, defaults to n, i.e. the partitions
do not overlap. **If a pad collection is not supplied, any tail elements
that remain from dividing the input collection length by n will not be
included in a partition.** If a pad collection is supplied, use its elements as
necessary to complete last partition upto n items. In case there are
not enough padding elements, return a partition with less than n items.

Patch: clj-1117.patch



 Comments   
Comment by Andy Fingerhut [ 29/Nov/12 2:15 PM ]

That would be a potentially breaking change for some people's code that uses partition. partition-all behaves as you wish.

Also, your concern with the documentation is for when there are padding elements specified as an argument, but your examples don't specify any padding elements.

Comment by Timothy Baldridge [ 29/Nov/12 2:55 PM ]

I agree, but I think the docs should then explicitly state: "if no padding is given, not all input elements may be returned in the output partitions" or something to that line.

Comment by Andy Fingerhut [ 29/Nov/12 4:43 PM ]

More precise documentation of current behavior is always welcome in my opinion.

Comment by Gabriel Horner [ 17/May/13 10:14 AM ]

I've uploaded a patch that calls out when and how partition drops tail elements:
"If a pad collection is not supplied, any tail elements that remain from dividing the input collection length by n will not be included in a partition."

Comment by Andrea Richiardi [ 11/Apr/15 10:38 AM ]

I was a little bit baffled by this as well...in particular, I could not figure out why (partition 2 3 [1 2 3 4 5 6 7]) is not '((1 2) (4 5) (7))...it would really be better to rewrite that comment.

Comment by Stuart Halloway [ 06/Sep/17 7:49 PM ]

I do not find the new wording more clear. Also it does not s/less/fewer





[CLJ-976] Implement reader literal and print support for PersistentQueue data structure Created: 27/Apr/12  Updated: 15/May/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: None

Type: Feature Priority: Minor
Reporter: Fogus Assignee: Fogus
Resolution: Unresolved Votes: 6
Labels: data-structures, queue, reader, tagged-literals

Attachments: File CLJ-976-queue-literal-eval-and-synquote.diff     Text File clj-976-queue-literal-eval-and-synquote-patch-v3.txt     File CLJ-976-queue-literal-eval.diff    

 Description   

Clojure's PersistentQueue structure has been in the language for quite some time now and has found its way into a fair share of codebases. However, the creation of queues is a two step operation often of the form:

(conj clojure.lang.PersistentQueue/EMPTY :a :b :c)

;=> #<PersistentQueue clojure.lang.PersistentQueue@78d5f6bc>

A better experience might be the following:

#queue [:a :b :c]

;=> #queue [:a :b :c]

(pop #queue [:a :b :c])

;=> #queue [:b :c]

This syntax is proposed and discussed in the Clojure-dev group at https://groups.google.com/forum/?fromgroups#!topic/clojure-dev/GQqus5Wycno

Open question: Should the queue literal's arguments eval? The implications of this are illustrated below:

;; non-eval case
#queue [1 2 (+ 1 2)]

;=> #queue [1 2 (+ 1 2)]


;; eval case
#queue [1 2 (+ 1 2)]

;=> #queue [1 2 3]

The answer to this open question will determine the implementation.



 Comments   
Comment by Steve Miner [ 27/Apr/12 10:18 AM ]

I think the non-eval behavior would be consistent with the other reader literals in Clojure 1.4. It's definitely better for interop where some other language implementation could be expected to handle a few literal representations, but not the evaluation of Clojure expressions. Use a regular function if the args need evaluation.

Comment by Chas Emerick [ 27/Apr/12 10:19 AM ]

The precedent of records seems relevant:

=> (defrecord A [b])
user.A
=> #user.A[(+ 4 5)]
#user.A{:b (+ 4 5)}
=> #user.A{:b (+ 4 5)}
#user.A{:b (+ 4 5)}

This continues to make sense, as otherwise queues would need to print with an extra (quote …) form around lists — which records neatly avoid:

=> (A. '(+ 4 5))
#user.A{:b (+ 4 5)}

Does this mean that a queue fn (analogous to vector, maybe) will also make an appearance? It'd be handy for HOF usage.

Comment by Fogus [ 27/Apr/12 11:00 AM ]

Added a patch for the tagged literal support ONLY. This is only one part of the total solution. This provides the read-string and printing capability. I'd like more discussion around the eval side before I get dive into the compiler.

Comment by Paul Bauer [ 27/Apr/12 6:45 PM ]

In addition to Chas' observations on consistency with record literals, would eval in queue literals open up the same security hole as #=, needing to respect *read-eval*?
When needing eval inside a queue literal, embedding a #= seems more apropos.

Comment by Fogus [ 04/May/12 1:14 PM ]

Evalable queue literal support.

Comment by Andy Fingerhut [ 10/May/12 5:54 PM ]

Neither of the patches CLJ-976-queue-literal-tagged-parse-support-only.diff dated Apr 27, 2012 nor CLJ-976-queue-literal-eval.diff dated May 4, 2012 apply cleanly to latest master as of May 10, 2012.

Comment by Fogus [ 11/May/12 10:15 AM ]

Updated patch file to merge with latest master.

Comment by Fogus [ 20/Jul/12 1:14 PM ]

New patch with support fixed for syntax-quote.

Comment by Stuart Sierra [ 17/Aug/12 12:41 PM ]

Patch does not apply as of commit f5f4faf95051f794c9bfa0315e4457b600c84cef

Comment by Fogus [ 17/Aug/12 3:06 PM ]

Weird. I was able to download the CLJ-976-queue-literal-eval-and-synquote.diff patch and apply it to HEAD as of just now (f5f4faf95051f794c9bfa0315e4457b600c84cef). There were whitespace warnings, but the patch applied, compiles and passes all tests.

Comment by Andy Fingerhut [ 17/Aug/12 7:29 PM ]

With latest head I was able to successfully apply patch CLJ-976-queue-literal-eval-and-synquote.diff with this command:

git am --keep-cr -s < CLJ-976-queue-literal-eval-and-synquote.diff

with some warnings, but successfully applied. If I try it without the --keep-cr option, the patch fails to apply. I believe this is often a sign that either one of the files being patched, or the patch itself, contains CR/LF line endings, which some of the Clojure source files definitely do.

The command above (with --keep-cr) is currently the one recommended for applying patches on page http://dev.clojure.org/display/design/JIRA+workflow in section "Screening Tickets". I added the suggested --keep-cr option after running across another patch that applied with the option, but not without it.

Comment by Andy Fingerhut [ 28/Aug/12 5:45 PM ]

Presumptuously changing Approval from Incomplete back to Test, since the latest patch does apply cleanly if --keep-cr option is used.

Comment by Rich Hickey [ 08/Sep/12 6:48 AM ]

this needs more time

Comment by Fogus [ 18/Sep/12 8:15 AM ]

Rich,

Do you mind providing a little more detail? I would be happy to make any changes if needed. However, if it's just a matter of its relationship to EDN and/or waiting until the next release then I am happy to wait. In either case, I'd like to complete this or push it to the back of my mind. Thanks.

Comment by Andy Fingerhut [ 05/Oct/12 7:49 AM ]

clj-976-queue-literal-eval-and-synquote-patch-v2.txt dated Oct 5 2012 is identical to Fogus's patch CLJ-976-queue-literal-eval-and-synquote.diff dated Jul 20 2012. It simply removes one line addition to clojure.iml that Rich has since added in a different commit, so that this patch now applies cleanly to latest master.

Comment by Andy Fingerhut [ 16/Oct/12 12:20 PM ]

clj-976-queue-literal-eval-and-synquote-patch-v3.txt dated oct 16 2012 is identical to Fogus's patch CLJ-976-queue-literal-eval-and-synquote.diff dated Jul 20 2012. It simply removes one line addition to clojure.iml that Rich has since added in a different commit, so that this patch now applies cleanly to latest master.

Comment by Andy Fingerhut [ 20/Oct/12 12:26 PM ]

Fogus, with the recent commit of a patch for CLJ-1070, my touched-up patch clj-976-queue-literal-eval-and-synquote-patch-v3.txt dated Oct 16 2012 doesn't apply cleanly. In this case it isn't simply a few lines of context that have changed, it is the interfaces that PersistentQueue implements have been changed. It might be best if you take a look at the latest code and the patch and consider how it should be updated.

Comment by Steve Miner [ 06/Apr/13 8:07 AM ]

Related to CLJ-1078.

Comment by Alex Miller [ 22/Aug/13 10:38 PM ]

Moving back to Triaged as Rich has not vetted.





[CLJ-1743] Avoid compile-time static initialization of classes when using inheritance Created: 02/Jun/15  Updated: 25/Sep/17

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.6, Release 1.7
Fix Version/s: None

Type: Enhancement Priority: Critical
Reporter: Abe Fettig Assignee: Unassigned
Resolution: Unresolved Votes: 5
Labels: aot, compiler, interop

Attachments: Text File 0001-Avoid-compile-time-class-initialization-when-using-g.patch     Text File clj-1743-2.patch     Text File clj-1743-3.patch    
Patch: Code
Approval: Triaged

 Description   

I'm working on a project using Clojure and RoboVM. We use AOT compilation to compile Clojure to JVM classes, and then use RoboVM to compile the JVM classes to native code. In our Clojure code, we call Java APIs provided by RoboVM, which wrap the native iOS APIs.

But we've found an issue with inheritance and class-level static initialization code. Many iOS APIs require inheriting from a base object and then overriding certain methods. Currently, Clojure runs a superclass's static initialization code at compile time, whether using ":gen-class" or "proxy" to create the subclass. However, RoboVM's base "ObjCObject" class [1], which most iOS-specific classes inherit from, requires the iOS runtime to initialize, and throws an error at compile time since the code isn't running on a device.

CLJ-1315 addressed a similar issue by modifying "import" to load classes without running static initialization code. I've written my own patch which extends this behavior to work in ":gen-class" and "proxy" as well. The unit tests pass, and we're using this code successfully in our iOS app.

Patch: clj-1743-2.patch

Here's some sample code that can be used to demonstrate the current behavior (Full demo project at https://github.com/figly/clojure-static-initialization):

Demo.java
package clojure_static_initialization;

public class Demo {
  static {
    System.out.println("Running static initializers!");
  }
  public Demo () {
  }
}
gen_class_demo.clj
(ns clojure-static-initialization.gen-class-demo
  (:gen-class :extends clojure_static_initialization.Demo))
proxy_demo.clj
(ns clojure-static-initialization.proxy-demo)

(defn make-proxy []
  (proxy [clojure_static_initialization.Demo] []))

[1] https://github.com/robovm/robovm/blob/master/objc/src/main/java/org/robovm/objc/ObjCObject.java



 Comments   
Comment by Alex Miller [ 18/Jun/15 3:01 PM ]

No changes from previous, just updated to apply to master as of 1.7.0-RC2.

Comment by Alex Miller [ 18/Jun/15 3:03 PM ]

If you had a sketch to test this with proxy and gen-class, that would be helpful.

Comment by Abe Fettig [ 22/Jun/15 8:31 AM ]

Sure, what form would you like for the sketch code? A small standalone project? Unit tests?

Comment by Alex Miller [ 22/Jun/15 8:40 AM ]

Just a few lines of Java (a class with static initializer that printed) and Clojure code (for gen-class and proxy extending it) here in the test description that could be used to demonstrate the problem. Should not have any dependency on iOS or other external dependencies.

Comment by Abe Fettig [ 01/Jul/15 8:49 PM ]

Sample code added, let me know if I can add anything else!

Comment by Abe Fettig [ 27/Jul/15 2:21 PM ]

Just out of curiosity, what are the odds this could make it into 1.8?

Comment by