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[CLJ-1780] Test OOME from locals clearing change Created: 17/Jul/15  Updated: 30/Jul/15

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

Type: Defect Priority: Minor
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: regression
Environment:

1.8.0-alpha2


Attachments: Text File strengthen-clearing-test.patch    
Approval: Triaged

 Description   

IBM JDK 1.6 in test matrix is throwing errors from the new test for CLJ-1250 in 1.8.0-alpha2.

[java] ERROR in (test-closed-over-clearing) (Range.java:133)
     [java] expected: (number? (reduce + 0 (r/map identity (range 1.0E8))))
     [java]   actual: java.lang.OutOfMemoryError: null
     [java]  at clojure.lang.Range.forceChunk (Range.java:133)
     [java]     clojure.lang.Range.chunkedFirst (Range.java:150)
     [java]     clojure.core$chunk_first.invoke (core.clj:667)
     [java]     clojure.core.protocols/fn (protocols.clj:136)
     [java]     clojure.core.protocols$fn__6478$G__6473__6487.invoke (protocols.clj:19)
     [java]     clojure.core.protocols$seq_reduce.invoke (protocols.clj:31)
     [java]     clojure.core.protocols/fn (protocols.clj:95)
     [java]     clojure.core.protocols$fn__6452$G__6447__6465.invoke (protocols.clj:13)
     [java]     clojure.core.reducers$folder$reify__21452.coll_reduce (reducers.clj:126)
     [java]     clojure.core$reduce.invoke (core.clj:6519)
     [java]     clojure.test_clojure.reducers/fn (reducers.clj:95)
     [java]     clojure.test$test_var$fn__7669.invoke (test.clj:703)
     [java]     clojure.test$test_var.invoke (test.clj:703)
     [java]     clojure.test$test_vars$fn__7691$fn__7696.invoke (test.clj:721)
     [java]     clojure.test$default_fixture.invoke (test.clj:673)
     [java]     clojure.test$test_vars$fn__7691.invoke (test.clj:721)
     [java]     clojure.test$default_fixture.invoke (test.clj:673)
     [java]     clojure.test$test_vars.invoke (test.clj:717)
     [java]     clojure.test$test_all_vars.invoke (test.clj:727)
     [java]     clojure.test$test_ns.invoke (test.clj:746)
     [java]     clojure.core$map$fn__4553.invoke (core.clj:2624)
     [java]     clojure.lang.LazySeq.sval (LazySeq.java:40)
     [java]     clojure.lang.LazySeq.seq (LazySeq.java:49)
     [java]     clojure.lang.Cons.next (Cons.java:39)
     [java]     clojure.lang.RT.next (RT.java:681)
     [java]     clojure.core/next (core.clj:64)
     [java]     clojure.core$reduce1.invoke (core.clj:909)
     [java]     clojure.core$reduce1.invoke (core.clj:900)
     [java]     clojure.core$merge_with.doInvoke (core.clj:2936)
     [java]     clojure.lang.RestFn.applyTo (RestFn.java:139)
     [java]     clojure.core$apply.invoke (core.clj:632)
     [java]     clojure.test$run_tests.doInvoke (test.clj:761)
     [java]     clojure.lang.RestFn.applyTo (RestFn.java:137)
     [java]     clojure.core$apply.invoke (core.clj:630)
     [java]     user$eval28810.invoke (run_test.clj:8)
     [java]     clojure.lang.Compiler.eval (Compiler.java:6850)


 Comments   
Comment by Nicola Mometto [ 18/Jul/15 12:02 AM ]

I don't understand how forcing a 32 element chunk could consume the memory. If locals clearing worked properly there should be no other part of that sequence in memory but I might be missing some detail.

Might there be something going on with the recent change in impl for Range?

Comment by Ghadi Shayban [ 18/Jul/15 12:19 AM ]

An interesting note is that (reduce + 0 (r/map identity (range 1e8))) is going through the seq path, despite reducers && reducible range. This is because coll-reduce doesn't prefer IReduceInit.

The CLJ-1250 test should be modified to intentionally hold the head of a seq in order to exercise the locals clearing. A good hypothesis from Alex is that GC is a bit slower on the archaic IBM JDK.

Comment by Ghadi Shayban [ 18/Jul/15 1:21 AM ]

I can't reproduce this on Linux x86-64 with IBM JDK and an artificially tiny heap.

[ghadi@amdhex ibm-java-x86_64-60]$ ./bin/java -Xmx128m -cp $HOME/jsr166y-1.7.0.jar:$HOME/clojure-1.8.0-master-SNAPSHOT.jar clojure.main
Clojure 1.8.0-master-SNAPSHOT
user=> (require '[clojure.core.reducers :as r])
nil
user=> (number? (reduce + 0 (r/map identity (range 1e8))))
true

Can you post details on the IBM JDK environment in CI? Need point release, heap size, kernel, distro, and jvm opts.

I've strengthened the CLJ-1250 test case by relying on neither reducer impl nor range impl, and I reverified that the bug is in fact present on <1.7 and gone on -master using Oracle JDK and 128m heap.

Comment by Alex Miller [ 18/Jul/15 8:52 AM ]

OS is CentOS 5.5 afaict

JDK details:

java version "1.6.0"
Java(TM) SE Runtime Environment (build pxa6460sr9fp2-20110625_01(SR9 FP2))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 Linux amd64-64 jvmxa6460sr9-20110624_85526 (JIT enabled, AOT enabled)
J9VM - 20110624_085526
JIT - r9_20101028_17488ifx17
GC - 20101027_AA)
JCL - 20110530_01

As far as I can tell, nothing is being done to alter the default heap size or other jvm opts during the build.

Comment by Ghadi Shayban [ 18/Jul/15 2:27 PM ]

The IBM JDK6 version I used was:

java version "1.6.0"
Java(TM) SE Runtime Environment (build pxa6460sr16fp7-20150708_01(SR16 FP7))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 Linux amd64-64 jvmxa6460sr16fp7-20150701_255724 (JIT enabled, AOT enabled)
J9VM - 20150701_255724
JIT - r9_20150630_95420
GC - GA24_Java6_SR16_20150701_1008_B255724)
JCL - 20150628_01

Seems like SR16 FP7 == 6.0.16.7, and the one on the CI build is SR9 FP2 == 6.0.9.2, a four or five year difference between point releases.

Comment by Ghadi Shayban [ 18/Jul/15 2:51 PM ]

OK I found a download for the (old) IBM JDK 6.0.9.2 and installed it on Linux x86-64. I cannot reproduce the bug.

Comment by Alex Miller [ 18/Jul/15 3:53 PM ]

I'd be happy to update the ibm jdk 1.6 version and n the build box too to see what happens.





[CLJ-1771] Support for multiple key(s)-value pairs in assoc-in Created: 29/Jun/15  Updated: 23/Jul/15

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

Type: Enhancement Priority: Major
Reporter: Griffin Smith Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None
Environment:

All


Attachments: Text File clj-1771.patch    
Approval: Triaged

 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


 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.





[CLJ-1770] atom watchers are not atomic with respect to reset! Created: 29/Jun/15  Updated: 31/Jul/15

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

Type: Defect Priority: Major
Reporter: Eric Normand Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: atom

Attachments: Text File atom-reset-atomic-watch-2015-06-30.patch     File timingtest.clj    
Patch: Code and Test
Approval: Triaged

 Description   

It is possible that two threads calling `reset!` on an atom can interleave, causing the corresponding watches to be called with the same old value but different new values. This contradicts the guarantee that atoms update atomically.

(defn reset-test []
  (let [my-atom (atom :start
                      :validator (fn [x] (Thread/sleep 100) true))
        watch-results (atom [])]
    (add-watch my-atom :watcher (fn [k a o n] (swap! watch-results conj [o n])))
  
    (future (reset! my-atom :next))
    (future (reset! my-atom :next))
    (Thread/sleep 500)
    @watch-results))

(reset-test)

Yields [[:start :next] [:start :next]]. Similar behavior can be observed when mixing reset! and swap!.

Expected behavior

Under atomic circumstances, (reset-test) should yield [[:start :next] [:next :next]]. This would "serialize" the resets and give more accurate information to the watches. This is the same behavior one would achieve by using (swap! my-atom (constantly :next)).

(defn swap-test []
  (let [my-atom (atom :start
                      :validator (fn [x] (Thread/sleep 100) true))
        watch-results (atom [])]
    (add-watch my-atom :watcher (fn [k a o n] (swap! watch-results conj [o n])))
  
    (future (swap! my-atom (constantly :next)))
    (future (swap! my-atom (constantly :next)))
    (Thread/sleep 500)
    @watch-results))

(swap-test)

Yields [[:start :next] [:next :next]]. The principle of least surprise suggests that these two functions should yield similar output.

Alternative expected behavior

It could be that atoms and reset! do not guarantee serialized updates with respect to calls to watches. In this case, it would be prudent to note this in the docstring for atom.

Analysis

The code for Atom.reset non-atomically reads and sets the internal AtomicReference. This allows for multiple threads to interleave the gets and sets, resulting in holding a stale value when notifying watches. Note that this should not affect the new value, just the old value.

Approach

Inside Atom.reset(), validation should happen first, then a loop calling compareAndSet on the internal state (similar to how it is implemented in swap()) should run until compareAndSet returns true. Note that this is still faster than the swap! constantly pattern shown above, since it only validates once and the tighter loop should have fewer interleavings. But it has the same watch behavior.

public Object reset(Object newval){
    validate(newval);
    for(;;)
        {
            Object oldval = state.get();
            if(state.compareAndSet(oldval, newval))
                {
                    notifyWatches(oldval, newval);
                    return newval;
                }
        }
}


 Comments   
Comment by Eric Normand [ 30/Jun/15 9:24 AM ]

I've made a test just to back up the timing claims I made above. If you run the file timingtest.clj, it will run code with both reset! and swap! constantly, with a validator that sleeps for 10ms. In both cases, it will print out the number of uniques (should be equal to number of reset!s, in this case 1000) and the time (using clojure.core/time). The timing numbers are relative to the machine, so should not be taken as absolutes. Instead, the ratio between them is what's important.

Run with: java -cp clojure-1.7.0-master-SNAPSHOT.jar clojure.main timingtest.clj

Results

Existing implementation:

"Elapsed time: 1265.228 msecs"
Uniques with reset!: 140
"Elapsed time: 11609.686 msecs"
Uniques with swap!: 1000
"Elapsed time: 7010.132 msecs"
Uniques with swap! and reset!: 628

Note that the behaviors differ: swap! serializes the watchers, reset! does not (# of uniques).

Suggested implementation:

"Elapsed time: 1268.778 msecs"
Uniques with reset!: 1000
"Elapsed time: 11716.678 msecs"
Uniques with swap!: 1000
"Elapsed time: 7015.994 msecs"
Uniques with swap! and reset!: 1000

Same tests being run. This time, they both serialize watchers. Also, the timing has not changed significantly.

Comment by Eric Normand [ 30/Jun/15 10:16 AM ]

Adding atom-reset-atomic-watch-2015-06-30.patch. Includes test and implementation.





[CLJ-1768] quote of an empty lazyseq produces an error when evaled Created: 24/Jun/15  Updated: 24/Jun/15

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

Type: Defect Priority: Minor
Reporter: Tim Engler Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None

Approval: Triaged

 Description   
user=> (eval `'())
()
user=> `'~(map identity ())
(quote ())
user=> (eval `'~(map identity ()))    ;; expected: ()
CompilerException java.lang.UnsupportedOperationException: Unknown Collection type, compiling:(NO_SOURCE_PATH:5:1)
user=> (prn *e)
#error {
 :cause "Unknown Collection type"
 :via
 [{:type clojure.lang.Compiler$CompilerException
   :message "java.lang.UnsupportedOperationException: Unknown Collection type, compiling:(NO_SOURCE_PATH:5:1)"
   :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6730]}
  {:type java.lang.UnsupportedOperationException
   :message "Unknown Collection type"
   :at [clojure.lang.Compiler$EmptyExpr emit "Compiler.java" 2929]}]
 :trace
 [[clojure.lang.Compiler$EmptyExpr emit "Compiler.java" 2929]
  [clojure.lang.Compiler$BodyExpr emit "Compiler.java" 5905]
  [clojure.lang.Compiler$FnMethod doEmit "Compiler.java" 5453]
  [clojure.lang.Compiler$FnMethod emit "Compiler.java" 5311]
  [clojure.lang.Compiler$FnExpr emitMethods "Compiler.java" 3843]
  [clojure.lang.Compiler$ObjExpr compile "Compiler.java" 4489]
  [clojure.lang.Compiler$FnExpr parse "Compiler.java" 3983]
  [clojure.lang.Compiler analyzeSeq "Compiler.java" 6721]
  [clojure.lang.Compiler analyze "Compiler.java" 6524]
  [clojure.lang.Compiler eval "Compiler.java" 6779]
  [clojure.lang.Compiler eval "Compiler.java" 6745]
  [clojure.core$eval invoke "core.clj" 3081]
  ;; elided rest
nil
user=> (eval `'~(map identity '(x)))
(x)

Cause: In the empty list case, the compiler here sees a LazySeq. I suspect something earlier in the stack should be producing an empty list instead, but haven't tracked it back yet.






[CLJ-1765] areduce speed improvements Created: 19/Jun/15  Updated: 20/Jun/15

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

Type: Enhancement Priority: Major
Reporter: Karsten Schmidt Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: ft, performance
Environment:

OSX 10.8.5, Oracle JDK1.8.0_25-b17


Attachments: Text File clj-1765.patch    
Patch: Code
Approval: Triaged

 Description   

Two performance improvements for areduce:

1. Call alength once, rather than every iteration
2. Use unchecked-inc-int instead of inc since array indices are limited to int range

Example:

(def a (long-array (range 1000)))
(areduce a i ret 0 (+ ret (aget a i)))

Criterium quick-bench:

  • 1.7.0-RC2: 15.5 ms
  • RC2+patch: 7.7 ms

Patch: clj-1765.patch
Screened by: Alex Miller



 Comments   
Comment by Karsten Schmidt [ 19/Jun/15 7:08 PM ]

added patch w/ changes described above





[CLJ-1764] partition-by runs infinite loop when one element of infinite partition is accessed Created: 19/Jun/15  Updated: 23/Jul/15

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

Type: Defect Priority: Minor
Reporter: Leon Grapenthin Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: newbie

Attachments: Text File clj-1764.patch    
Approval: Triaged

 Description   
(def x (partition-by zero? (range)))
(first x)
;-> (0)
(first (second x))
;-> infinite loop

The reason is that partition-by counts and thus realizes each current partition to call itself recursively.

It seems like unexpected behavior, since the user may not intend to realize the entire partition.

It can be fixed by changing seq to lazy-seq in its last line.



 Comments   
Comment by Matthew Gilliard [ 23/Jul/15 2:36 PM ]

Patch as suggested by Leon, + test.





[CLJ-1763] clojure.core/sort is not thread-safe on Java collections with backing arrays Created: 19/Jun/15  Updated: 30/Jul/15

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

Type: Enhancement Priority: Minor
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: collections

Attachments: Text File 0001-CLJ-1763-make-sort-thread-safe.patch    
Patch: Code
Approval: Triaged

 Description   

If a (mutable) Java collection that exposes it's backing array is passed to c.c/sort in multiple threads, the collection will be concurrently modified in multiple threads.

user=> (def q (java.util.concurrent.ArrayBlockingQueue. 1))
#'user/q
user=> (future (loop [] (.add q 1) (.remove q 1) (recur)))
#object[clojure.core$future_call$reify__4393 0x4769b07b {:status :pending, :val nil}]
user=> (take 3 (distinct (repeatedly #(sort q))))
((1) () nil)

Approach: Convert coll to a seq before converting it to an array, thus preserving the original collection.

Patch: 0001-CLJ-1763-make-sort-thread-safe.patch

Alternate approaches:

1. Document in sort that, like Java arrays, Java collections backed by arrays are modified in-place.
2. Change RT.toArray() to defensively copy the array returned from a (non-IPersistentCollection) Java collection. This has a number of potential ramifications as this method is called from several paths.
3. For non-Clojure collections, could also use Collections.sort() instead of dumping to array and using Arrays.sort().



 Comments   
Comment by Alex Miller [ 19/Jun/15 10:55 AM ]

The docstring says "If coll is a Java array, it will be modified. To avoid this, sort a copy of the array." which also seems like solid advice in this case.

Creating a sequence view of the input collection would significantly alter the performance characteristics.

Comment by Alex Miller [ 19/Jun/15 10:59 AM ]

I guess what I'm saying is, we should not make the performance worse for persistent collections in order to make it safer for arbitrary Java collections. But it may still be useful to make it safer without affecting persistent collection performance and/or updating the docstring.

Comment by Nicola Mometto [ 19/Jun/15 11:02 AM ]

Alex, no additional sequence is being created, the seq call was already there

Comment by Alex Miller [ 19/Jun/15 11:53 AM ]

Well, that's kind of true. The former use did not force realization of the whole seq, just the first element. That said, from a quick test the extra cost seems small on a set (vector seqs are actually faster due to their structure).

Comment by Stuart Halloway [ 30/Jul/15 9:11 AM ]

I think this should be a docstring change, if anything at all.





[CLJ-1762] Implement IKVReduce for java.util.map Created: 18/Jun/15  Updated: 18/Jun/15

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

Type: Enhancement Priority: Minor
Reporter: Chen Guo Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: interop, performance

Attachments: Text File reduce-kv-java-map.patch    
Patch: Code
Approval: Triaged

 Description   

reduce works on Java maps, but reduce-kv does not:

user=> (def clojure-map {1 2 3 4})
#'user/clojure-map
user=> (def java-map (java.util.HashMap. {1 2 3 4}))
#'user/java-map
user=> (reduce (fn [sum [k v]] (+ sum k v)) 0 java-map)
10
user=> (reduce-kv + 0 clojure-map)
10
user=> (reduce-kv + 0 java-map)

IllegalArgumentException No implementation of method: :kv-reduce of protocol: #'clojure.core.protocols/IKVReduce found for class: java.util.HashMap  clojure.core/-cache-protocol-fn\
 (core_deftype.clj:544)

It's trivial to destructure arguments in a regular reduce, but there are performance implications. The following example yields a 7x speed up when run with the implementation of reduce-kv for java.util.Map as implemented in this patch:

user=> (def big-clojure-map (into {} (map #(vector % %) (range 10000))))
#'user/big-clojure-map
user=> (def big-java-map (java.util.HashMap. big-clojure-map))
Reflection warning, /tmp/form-init7130245387362554027.clj:1:19 - call to java.util.HashMap ctor can't be resolved.
#'user/big-java-map
user=> (defn reduce-sum [m] (reduce (fn [sum [k v]] (+ sum k v)) 0 m))
#'user/reduce-sum
user=> (defn reduce-sum-kv [m] (reduce-kv (fn [sum k v] (+ sum k v)) 0 m))
#'user/reduce-sum-kv
user=> (time (dotimes [_ 1000] (reduce-sum big-java-map)))
"Elapsed time: 2624.692113 msecs"
nil
user=> (time (dotimes [_ 1000] (reduce-sum-kv big-java-map)))
"Elapsed time: 376.802454 msecs"
nil





[CLJ-1759] macroexpand throws runtime exception on symbol bound to a class Created: 17/Jun/15  Updated: 18/Jun/15

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

Type: Defect Priority: Minor
Reporter: W. David Jarvis Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler
Environment:

OSX 10.10.3, Leiningen 2.5.1, Java 1.8.0_45 64-bit.


Attachments: Text File clj-1759.patch    
Patch: Code
Approval: Triaged

 Description   

The use of macroexpand on short class name symbols triggers a RuntimeException.

user=> (import 'java.net.URI)
java.net.URI
user=> (macroexpand '(java.net.URI "http://google.com")) ;; fine
(java.net.URI "http://google.com")
user=> (macroexpand '(URI "http://google.com")) ;; huh?
java.lang.RuntimeException: Expecting var, but URI is mapped to class java.net.URI
user=> (pst *e)
RuntimeException Expecting var, but URI is mapped to class java.net.URI
	clojure.lang.Util.runtimeException (Util.java:221)
	clojure.lang.Compiler.lookupVar (Compiler.java:7092)
	clojure.lang.Compiler.isMacro (Compiler.java:6571)
	clojure.lang.Compiler.macroexpand1 (Compiler.java:6626)
	clojure.core/macroexpand-1 (core.clj:3870)
	clojure.core/macroexpand (core.clj:3879)

Neither of these should throw an error during macroexpansion (basically should be same after expansion. Both should throw the same error when evaluated (ClassCast trying to invoke a Class as an IFn).

Approach: Throw the runtime error in lookupVar only if internNew is true. In that case we unexpectedly found something other than a var and should still report. Otherwise, just let lookupVar flow through to return a null (no var found.



 Comments   
Comment by Alex Miller [ 18/Jun/15 6:19 AM ]

The compiler is trying to determine if the thing in function position is a var that is a macro that requires expansion in Compiler.isMacro().

In the case of (java.net.URI "http://google.com"), lookupVar determines that java.net.URI is an unmapped symbol and does nothing, meaning no expansion is necessary (this of course will fail at evaluation time with "ClassCastException java.lang.Class cannot be cast to clojure.lang.IFn").

In the case of (URI "http://google.com"), lookupVar finds a symbol mapped to something that's not a var and throws the RuntimeException that is seen.

I would expect that neither of these should throw an error during macroexpansion (basically the same thing they start as) and that both should throw the same error when evaluated. Attaching a patch that will only throw the error if internNew - in that case you unexpectedly found something other than a var and you should still report (otherwise, just return null - lookupVar didn't find a var).

The internNew case comes up with:

(import java.net.URI) 
(def URI "abc") ;; java.lang.RuntimeException: Expecting var, but URI is mapped to class java.net.URI

with the patch:

user=> (macroexpand '(java.net.URI "http://google.com")) 
(java.net.URI "http://google.com") 
user=> (macroexpand '(URI "http://google.com")) 
(URI "http://google.com") 
user=> (java.net.URI "http://google.com") 
ClassCastException java.lang.Class cannot be cast to clojure.lang.IFn user/eval9 (NO_SOURCE_FILE:6) 
user=> (URI "http://google.com") 
ClassCastException java.lang.Class cannot be cast to clojure.lang.IFn user/eval11 (NO_SOURCE_FILE:7)




[CLJ-1755] Calling nth on TransientVector with a default will not check if the transient has been made persistent Created: 16/Jun/15  Updated: 16/Jun/15

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

Type: Defect Priority: Minor
Reporter: Patrick Gombert Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: transient

Attachments: Text File transient-vector-nth.patch    
Patch: Code
Approval: Triaged

 Description   

Invoking nth with arity two on a TransientVector will ensure that the transient is editable. However, invoking with arity three will return the supplied not-found value if the index is out of range.



 Comments   
Comment by Alex Miller [ 16/Jun/15 9:42 AM ]

Can you add an example to the description and a test to the patch?





[CLJ-1752] realized? return true for an instance that is not IPending Created: 09/Jun/15  Updated: 09/Jun/15

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

Type: Enhancement Priority: Minor
Reporter: Logan Linn Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None

Approval: Triaged

 Description   

To safely test if an arbitrary seq is realized (non-lazy), we need a wrapper like:

(defn seq-realized? [s]
  (if (instance? clojure.lang.IPending s)
    (realized? s)
    true))

If realized? returned true for an (ISeq?) instance that is not IPending there would be less surprising behavior for cases such as, (realized? (range 10)) which throws exception.

NB: A follow-up to CLJ-1751.






[CLJ-1750] There should be a way to observe platform features at runtime Created: 08/Jun/15  Updated: 30/Jul/15

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

Type: Enhancement Priority: Major
Reporter: Luke VanderHart Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: reader

Approval: Triaged

 Description   

Reader conditionals let the reader emit code conditionally based upon a set of platform features.

This is a closed set - however, currently it is baked in as an implementation detail of the reader. Runtime code cannot access the current platform feature set.

This is problematic when writing a macro that needs to emit code conditionally based upon the platform of the code being compiled. Reader conditionals themselves won't work since macros are always themselves read in Clojure.

We should enable some mechanism for retrieving the current platform at runtime, or at least at macro expansion time.

For example, this is the kind of thing it should be possible to do:

(defmacro mymacro []
    (if (*platforms* :clj)
      `(some-clojure-thing)
      `(some-cljs-thing)))


 Comments   
Comment by Micah Martin [ 19/Jun/15 1:46 PM ]

+1 - Would very much like to see this in 1.7. Currently I have to use an ugly hack.

(def ^:private ^:no-doc cljs? (boolean (find-ns 'cljs.analyzer)))





[CLJ-1743] Avoid compile-time static initialization of classes when using inheritance Created: 02/Jun/15  Updated: 27/Jul/15

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

Type: Enhancement Priority: Major
Reporter: Abe Fettig Assignee: Unassigned
Resolution: Unresolved Votes: 3
Labels: aot, compiler, interop

Attachments: Text File 0001-Avoid-compile-time-class-initialization-when-using-g.patch     Text File clj-1743-2.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 Alex Miller [ 27/Jul/15 6:06 PM ]

unknown.





[CLJ-1733] print-dup form unreadable for sorted sets and maps Created: 19/May/15  Updated: 31/Jul/15

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

Type: Defect Priority: Major
Reporter: Nikita Prokopov Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None
Environment:

Clojure 1.6.0
Clojure 1.7.0-alpha5
Clojure 1.7.0-beta3

java version "1.8.0"
Java(TM) SE Runtime Environment (build 1.8.0-b132)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b70, mixed mode)


Attachments: Text File clj-1733-tagged-literals-throw-on-sorted-set.patch    
Patch: Code and Test
Approval: Triaged

 Description   

print-dup for sorted sets and maps presume a nonexistent static create method that takes an IPersistentCollection

Printing

user=> (print-dup (sorted-set 1) *out*)
#=(clojure.lang.PersistentTreeSet/create [1])

Can't read back

(read-string "#=(clojure.lang.PersistentTreeSet/create [1])")
ClassCastException Cannot cast clojure.lang.PersistentVector to clojure.lang.ISeq  java.lang.Class.cast (Class.java:3356)

Possible Fixes

  • add create methods taking IPersistentVector to collections
  • emit something different from print-dup


 Comments   
Comment by Alex Miller [ 19/May/15 4:55 PM ]

It's trying to invoke PersistentTreeSet.create(ISeq) with ["123"]. It's not clear to me where the vector comes from?

Comment by Nikita Prokopov [ 19/May/15 5:04 PM ]

It’s a particular case of CLJ-1461. Vector comes from reading output of print-dup:

(defrecord Rec [f])

(binding [*print-dup* true]
  (prn (Rec. (sorted-set 1))))
;; => #tonsky.Rec[#=(clojure.lang.PersistentTreeSet/create [1])]

I already have a patch for PersistentTreeSet (attached here). Can look into CLJ-1461 later.





[CLJ-1732] Add docstring explanation of (isa? [x1 x2...] [parent1 parent2...]) Created: 17/May/15  Updated: 17/May/15

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

Type: Enhancement Priority: Minor
Reporter: Phill Wolf Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: docstring

Approval: Triaged

 Description   

The "Multimethods and Hierarchies" page mentions that "isa?" has special behavior when aimed at two vectors[1]. But the docstring of "isa?" does not mention it[2].

[1] http://clojure.org/multimethods
[2] http://clojure.github.io/clojure/clojure.core-api.html#clojure.core/isa?






[CLJ-1730] Improve `refer` performance Created: 13/May/15  Updated: 13/May/15

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

Type: Enhancement Priority: Major
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: performance

Attachments: Text File refer-perf.patch    
Patch: Code
Approval: Triaged

 Description   

refer underlies require, use, and refer-clojure use cases and is not particularly efficient at its primary job of copying symbol/var mapping from one namespace to another.

Approach: Some improvements that can be made:

  • Go directly to the namespace mappings and avoid creating filtered intermediate maps (ns-publics)
  • Use transients to build map of references to refer
  • Instead of cas'ing each new reference individually, build map of all changes, then cas
  • For (:require :only ...) case - instead of walking all referred vars and looking for matches, walk only the included vars and look up each one

There are undoubtedly more dramatic changes (like immutable namespaces) in how all this works that could further improve performance but I tried to make the scope small-ish for this change.

While individual refer timings are greatly reduced (~50% reduction for (refer clojure.core), ~90% reduction for :only use), refer is only a small component of broader require load times so the improvements in practice are modest.

Performance:

expr in a new repl 1.7.0-beta3 1.7.0-beta3+patch
(in-ns 'foo) (clojure.core/refer 'clojure.core) 2.65 ms 0.994 ms
(in-ns 'bar) (clojure.core/refer 'clojure.core :only '[inc dec]) 1.04 ms 0.113 ms
(use 'criterium.core) 0.877 ms 0.762 ms
(require '[clojure.core.async :refer (>!! <!! chan close!)]) 3408 ms 3302 ms

Patch: refer-perf.patch






[CLJ-1724] Reuse call to seq() in LazySeq/hashcode for else case Created: 04/May/15  Updated: 04/May/15

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

Type: Enhancement Priority: Minor
Reporter: Jozef Wagner Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: collections, ft, performance

Attachments: File clj-1724.diff    
Patch: Code
Approval: Triaged

 Description   

In LazySeq/hashCode, seq() is called twice for non-empty seqs. First call to seq() can be reused in else case.






[CLJ-1714] Some static initialisers still run at compile time if used in type hints Created: 22/Apr/15  Updated: 31/Jul/15

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

Type: Defect Priority: Minor
Reporter: Adam Clements Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: compiler, typehints

Attachments: Text File CLJ-1714.patch    
Patch: Code
Approval: Triaged

 Description   

AOT compiling on an x86 machine to be run on an ARM machine when a Java dependency has a native component and the class with the native dependency is used in a type hint.

In this situation, the only native library available on the classpath is the ARM dependency, and obviously won't load on the compiling x86 machine. Java libraries tend to load the native dependencies in the static initialiser of the class, which will fail in this situation as the architecture is x86 and the dependencies are ARM, for which reason CLJ-1315 made the change to not run static initialisers at compile time.

This covers a case which didn't come up as part of CLJ-1315, that the same problem occurs if rather than constructing the class, you simply use it as a type hint (which IMO is doubly surprising as something to have a side-effect).

This patch fixes that - happy to try and create a test, but would appreciate some advice on the shape such a test would take - presumably loading a java native library would be undesirable. I could simply check for static initialisers being run, but first would need some agreement that this is universally undesirable at compile time.

I have been using this patch in production for over a year with no adverse effects (as has anybody using the clojure-android build of clojure).



 Comments   
Comment by Alex Miller [ 22/Apr/15 10:53 AM ]

I think this might have been logged already but I'm not sure.

Comment by Michael Blume [ 22/Apr/15 12:30 PM ]

Patch won't apply to master for me

Comment by Adam Clements [ 22/Apr/15 2:39 PM ]

Really sorry, don't know what happened there. I checked out a fresh copy of the repo and re-applied the changes, deleted the old patch as it was garbage. Try the new one, timestamped 2:37pm

Comment by Stuart Halloway [ 30/Jul/15 1:52 PM ]

Please add an example of the problem, and if possible a failing test.

Comment by Alex Miller [ 30/Jul/15 5:14 PM ]

Reset to "Open" as moving from Triaged->Incomplete is not valid in our current workflow.

Comment by Adam Clements [ 31/Jul/15 10:56 AM ]

Example problem:
AOT compiling on an x86 machine to be run on an ARM machine when a Java dependency has a native component and the class with the native dependency is used in a type hint.

In this situation, the only native library available on the classpath is the ARM dependency, and obviously won't load on the compiling x86 machine. Java libraries tend to load the native dependencies in the static initialiser of the class, which will fail in this situation as the architecture is x86 and the dependencies are ARM, for which reason CLJ-1315 made the change to not run static initialisers at compile time.

This covers a case which didn't come up as part of CLJ-1315, that the same problem occurs if rather than constructing the class, you simply use it as a type hint (which IMO is doubly surprising as something to have a side-effect).

This patch fixes that - happy to try and create a test, but would appreciate some advice on the shape such a test would take - presumably loading a java native library would be undesirable. I could simply check for static initialisers being run, but first would need some agreement that this is universally undesirable at compile time.

I have been using this patch in production for over a year with no adverse effects (as has anybody using the clojure-android build of clojure).

Comment by Stuart Halloway [ 31/Jul/15 11:34 AM ]

Hi Adam,

Thanks for the quick response. I think checking for static initializers being run is OK for a test.





[CLJ-1708] Volatile mutable in deftype is not settable when using try..finally and returning this Created: 17/Apr/15  Updated: 31/Jul/15

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

Type: Defect Priority: Minor
Reporter: Patrick Gombert Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler, deftype
Environment:

clojure 1.6.0, clojure 1.7.0-beta1


Approval: Triaged

 Description   

Reproducible Code: https://gist.github.com/patrickgombert/1bcb8a051aeb3e82d855

When using a volatile-mutable field in deftype, compilation fails if the field is set! in a method call that uses both try..finally and returns itself from the method call. Leaving out either the try..finally or returning itself from the method causes compilation to succeed.

Expected behavior: set! should set the volatile-mutable variable and compilation should succeed.



 Comments   
Comment by Kevin Downey [ 17/Apr/15 7:15 PM ]

this must be the same issue as CLJ-1422 and CLJ-701, it has nothing to do with returning `this`, but with the try being in a tail position or not. if the try is not in a tail position the compiler hoists it out in to a thunk. effectively the code is

(deftype SomeType [^:volatile-mutable foo]
  SomeProtocol
  (someFn [_] ((fn [] (try (set! foo 1))))))

which the compiler also rejects, because it doesn't let you mutate fields from functions that are not the immediate protocol functions





[CLJ-1705] vector-of throws NullPointerException if given unrecognized type Created: 14/Apr/15  Updated: 06/May/15

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: Release 1.4, Release 1.6
Fix Version/s: None

Type: Defect Priority: Minor
Reporter: John Croisant Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: checkargs, errormsgs, newbie
Environment:

MacOS X Version 10.9.5

java version "1.8.0_11"
Java(TM) SE Runtime Environment (build 1.8.0_11-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.11-b03, mixed mode)


Attachments: Text File clj-1705-2.patch     Text File clj-1705-3.patch     Text File CLJ-1705.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Summary:

If the user passes an unrecognized type keyword to vector-of, it will throw a NullPointerException with no message. This gives no indication to the user of what the problem is, which can frustrate the user and make debugging harder than it needs to be.

Example:

user=> (vector-of :integer 1 2 3) ; user meant (vector-of :int 1 2 3)

NullPointerException   clojure.core/vector-of (gvec.clj:472)

Approach: Throw more informative error message than NPE with more info.

After:

user=> (vector-of :integer 1 2 3)
IllegalArgumentException Unrecognized type :integer  clojure.core/vector-of (gvec.clj:498)

Patch: clj-1705-3.patch



 Comments   
Comment by Johan Mena [ 05/May/15 12:12 AM ]

Here’s my proposed solution: https://github.com/jhn/clojure/commit/0522fffd7893e8c79969f5c6ac91a333484c8e23 — It works as expected and the tests pass.

One more thing I'm not sure about is how to create a patch for this. The ticket mentions "Release 1.4, Release 1.6” as affected versions, but I found this to still be present in 1.7 and in 1.5 too. Do I checkout only these two tags (1.4, 1.6) from the git repo and create a patch for each one separately? Or what's the usual way to go about it? I read through the Issue Tracking section of the wiki but it's still not very clear.

Thanks.

Johan

Comment by Alex Miller [ 05/May/15 7:09 AM ]

in general, just work from master. We don't generally back port to older versions.

You should make a patch following the instructions at http://dev.clojure.org/display/community/Developing+Patches

Comment by Andy Fingerhut [ 05/May/15 10:20 AM ]

Johan, are you listed as "johan (jhn)" on the contributor list here? http://clojure.org/contributing

If so, it would be good to update that listing to something like "Johan Mena (jhn)" for the time when someone needs to check that you have signed a Clojure CA, before your patch is committed.

Comment by Alex Miller [ 05/May/15 10:35 AM ]

I believe that's correct - I have updated the contributing page.

Comment by Johan Mena [ 05/May/15 1:57 PM ]

The patch I attached yesterday did start from master, so I think it's good to go for review.

Thanks Alex & Andy!

Comment by Alex Miller [ 06/May/15 9:56 AM ]

Ok, I looked at the patch. Functionally, seems ok other than that the find+destructuing doesn't seem to have a use over get.

However, I also looked at performance for the happy path using criterium and the following test:

(quick-bench (vector-of :int 1 2))

Before the patch: 27.418350 ns
After the patch: 79.883695 ns

The reason for this is that the prior code created a single map and constructed the array managers in there once, whereas the patch causes the array manager to be created each time through the code.

Re-extracting the map and replacing the find with get, I was back to: 34.320916 ns

I think that's too much of a hit for this change so I looked at a couple variants:

  • def'ing each am separately and using a `case` expression - 36.566750 ns
  • using `or` instead of if-let - 29.680252 ns

I think that last one is pretty close, but we're paying a hit just to invoke the new function, so my final stab was turning that into a macro - 28.411626 ns, which seems tolerable to me. Because I used a macro, I also had to move the type hints in vector-of to avoid reflection.

Since I had everything sitting here, I went ahead and made a new patch. I feel bad about replacing yours, but not sure what else makes sense to do.

Comment by Alex Miller [ 06/May/15 10:02 AM ]

Ok, I split up the patch into test and code commits so you have credit for some of the changes! Since it's got my stuff in here, this will have to wait till it gets added to 1.8 to get screened by someone else.

Comment by Johan Mena [ 06/May/15 11:04 AM ]

Haha, you shouldn't have bothered, but thanks!

And thanks for the detailed explanation! Actually 'get' was my first approach too but the (get map key not-found) form kept throwing the exception in the `not-found` part even in the happy case. I asked around and found out the else part needs to be evaluated in this case too. Someone suggested using a macro but I'm not very familiar with that just yet, so I went with if-let, which seemed readable. Just out of curiosity, when you tried the get approach, did you use (get map key) and check for nil to throw the exception?

I ran my code through the irc channel and got positive feedback, so completely forgot about performance. Will keep it in mind next time.





[CLJ-1693] into: merge metadata Created: 03/Apr/15  Updated: 03/Apr/15

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

Type: Enhancement Priority: Minor
Reporter: Gregg Reynolds Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: function, interop
Environment:

all


Approval: Triaged

 Description   

Currently (into to from) preserves to's metadata but discards from's metadata. The enhancement would be to have 'into' do something like (merge (meta to) (meta from)). Justification: as with data, so with metadata. Use case: Using deftype, I have a class EntityMap that clojurizes a native Java class (App Engine's Entity class), making it behave just like a clojure map. This includes using into to convert an EntityMap to an ordinary PersistentMap; the problem is that key information for the EntityMap is really metadata, so I need (into {} em) to put that metadata into the new PersistentMap.

See also CLJ-916






[CLJ-1682] clojure.set/intersection occasionally allows non-set arguments. Created: 24/Mar/15  Updated: 14/Jul/15

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

Type: Defect Priority: Minor
Reporter: Valerie Houseman Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: checkargs

Approval: Triaged

 Description   

clojure.set/intersection, by intent and documentation, is meant to be operations between two sets. However, it sometimes allows (and returns correct opreations upon) non-set arguments. This confuses the intention that non-set arguments are not to be used.

Here's an example with Set vs. KeySeq:
If there happens to be an intersection, you'll get a result. This may lead someone coding this to think that's okay, or to not notice they've used an incompatible data type. As soon as the intersection is empty, however, an appropriate type error ensues, albeit by accident because the first argument to clojure.core/disj should be a set.

user=> (require '[clojure.set :refer [intersection]])
nil
user=> (intersection #{:key_1 :key_2} (keys {:key_1 "na"}))   ;This works, but shouldn't
(:key_1)
user=> (intersection #{:key_1 :key_2} (keys {:key_3 "na"}))   ;This fails, because intersection assumes the second argument was a Set
ClassCastException clojure.lang.APersistentMap$KeySeq cannot be cast to clojure.lang.IPersistentSet  clojure.core/disj (core.clj:1449)

(disj (keys {:key_1 "na"}) #{:key_1 :key_2})   ;The assumption that intersection made
ClassCastException clojure.lang.APersistentMap$KeySeq cannot be cast to clojure.lang.IPersistentSet  clojure.core/disj (core.clj:1449)

Enforcing type security on a library that's clearly meant for a particular type seems like the responsible thing to do. It prevents buggy code from being unknowingly accepted as correct, until the right data comes along to step on the bear trap.



 Comments   
Comment by Andy Fingerhut [ 24/Mar/15 7:19 PM ]

CLJ-810 was similar, except it was for function clojure.set/difference. That one was declined with the comment "set/difference's behavior is not documented if you don't pass in a set." I do not know what core team will judge ought to be done with this ticket, but wanted to provide some history.

Dynalint [1] and I think perhaps Dire [2] can be used to add dynamic argument checking to core functions.

[1] https://github.com/frenchy64/dynalint
[2] https://github.com/MichaelDrogalis/dire

Comment by Alex Miller [ 24/Mar/15 9:00 PM ]

Now that `set` is faster for sets, I think we could actually add checking for sets in some places where we might not have before. So, it's worth looking at with fresh eyes.

Comment by Jason Wolfe [ 28/May/15 2:54 AM ]

Back in 2009 I submitted a patch to the set functions with explicit `set?` checks and Rich's response was "the fact that these functions happen to work when the second argument is not a set is an implementation artifact and not a promise of the interface, so I'm not in favor of the set? testing or any other accommodation of that." Not sure if that is still accurate though.





[CLJ-1680] quot and rem handle doubles badly Created: 24/Mar/15  Updated: 27/Jul/15

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

Type: Defect Priority: Minor
Reporter: Francis Avila Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: math

Attachments: Text File clj-1680_no_div0_jre17.patch    
Patch: Code and Test
Approval: Triaged

 Description   

quot and rem in the doubles case (where any one of the arguments is a floating point) gives strange results for non-finite arguments:

(quot Double/POSITIVE_INFINITY 2) ; Java: Infinity
NumberFormatException Infinite or NaN  java.math.BigDecimal.<init> (BigDecimal.java:808)
(quot 0 Double/NaN) ; Java: NaN
NumberFormatException Infinite or NaN  java.math.BigDecimal.<init> (BigDecimal.java:808)
(quot Double/POSITIVE_INFINITY Double/POSITIVE_INFINITY) ; Java: NaN
NumberFormatException Infinite or NaN  java.math.BigDecimal.<init> (BigDecimal.java:808)
(rem Double/POSITIVE_INFINITY 2) ; Java: NaN
NumberFormatException Infinite or NaN  java.math.BigDecimal.<init> (BigDecimal.java:808)
(rem 0 Double/NaN) ; Java: NaN
NumberFormatException Infinite or NaN  java.math.BigDecimal.<init> (BigDecimal.java:808)
(rem 1 Double/POSITIVE_INFINITY) ; The strangest one. Java: 1.0
=> NaN

quot and rem also do divide-by-zero checks for doubles, which is inconsistent with how doubles act for division:

(/ 1.0 0)
=> NaN
(quot 1.0 0) ; Java: NaN
ArithmeticException Divide by zero  clojure.lang.Numbers.quotient (Numbers.java:176)
(rem 1.0 0); Java: NaN
ArithmeticException Divide by zero  clojure.lang.Numbers.remainder (Numbers.java:191)

Attached patch does not address this because I'm not sure if this is intended behavior. There were no tests asserting any of the behavior mentioned above.

Fundamentally the reason for this behavior is that the implementation for quot and rem sometimes (when result if division larger than a long) take a double, coerce it to BigDecimal, then BigInteger, then back to a double. The coersion means it can't handle nonfinite intermediate values. All of this is completely unnecessary, and I think is just leftover detritus from when these methods used to return a boxed integer type (long or BigInteger). That changed at this commit to return primitive doubles but the method body was not refactored extensively enough.

The method bodies should instead be simply:

static public double quotient(double n, double d){
    if(d == 0)
        throw new ArithmeticException("Divide by zero");
    double q = n / d;
    return (q >= 0) ? Math.floor(q) : Math.ceil(q);
}

static public double remainder(double n, double d){
    if(d == 0)
        throw new ArithmeticException("Divide by zero");
    return n % d;
}

Which is what the attached patch does. (And I'm not even sure the d==0 check is appropriate.)

Even if exploding on non-finite results is a desirable property of quot and rem, there is no need for the BigDecimal+BigInteger coersion. I can prepare a patch that preserves existing behavior but is more efficient.

More discussion at Clojure dev.



 Comments   
Comment by Francis Avila [ 24/Mar/15 12:55 PM ]

More testing revealed that n % d does not preserve the relation (= n (+ (* d (quot n d)) (rem n d))) as well as (n - d * (quot n d)), which doesn't make sense to me since that is the very relation the spec says % preserves. % is apparently not simply Math.IEEEremainder() with a different quotient rounding.

Test case: (rem 40.0 0.1) == 0.0; 40.0 % 0.1 == 0.0999... (Smaller numerators will still not land at 0 precisely, but land closer than % does.)

Updated patch which rolls back some parts of the simplification to remainder and adds this test case.

Comment by Andy Fingerhut [ 04/Jul/15 12:12 AM ]

Francis, your patch clj-1680_no_div0.patch dated 2015-Mar-24 uses the method isFinite(), which appears to have been added in Java 1.8, and does not exist in earlier versions. I would guess that while the next release of Clojure may drop support for Java 1.6, it is less likely it would also drop support for Java 1.7 at the same time. It might be nice if your patch could use something like !(isInfinite() || isNaN()) instead, which I believe is equivalent, and both of those methods exist in earlier Java versions.

Comment by Francis Avila [ 26/Jul/15 11:22 PM ]

Updated patch with a java 1.7-compatible version, also rebased against master.

No tests fail except this one, which I don't think is related to this patch:

[java] FAIL in (gen-interface-source-file) (genclass.clj:151)
     [java] expected: (= "examples.clj" (str sourceFile))
     [java]   actual: (not (= "examples.clj" ""))
Comment by Michael Blume [ 27/Jul/15 1:34 PM ]

Francis, I tried downloading your patch and I didn't see any test failures at all. Do you see the same failure if you check out the master branch from the Clojure repo? Do you still see it if you mvn clean first? If so, it might be worth opening a ticket for it and seeing if anyone else can reproduce it.

Comment by Andy Fingerhut [ 27/Jul/15 1:41 PM ]

Yes, and if you do see a failure with unmodified Clojure for 'mvn clean test', or './antsetup.sh ; ant clean; ant', please let us know the OS and JVM you are using. I haven't seen that on the OS/JVM combos I have tried.

Comment by Francis Avila [ 27/Jul/15 2:51 PM ]

Nevermind, failing test went away after a clean. All tests pass.





[CLJ-1678] Update failing tests for IBM JDK 1.7 and 1.8 Created: 19/Mar/15  Updated: 20/Mar/15

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

Type: Defect Priority: Minor
Reporter: Andy Fingerhut Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: test
Environment:

IBM JDK 1.7 and 1.8


Approval: Triaged

 Description   

For Sun/Oracle JDKs, and IBM JDK 1.6, we have this:

user=> (.hashCode 9223372039002259457N)
1

For IBM JDKs 1.7 and 1.8, it changed to this (I do not know why):

user=> (.hashCode 9223372039002259457N)
33

This causes a few example-based tests in Clojure to fail when run on those IBM JDK versions. There does not appear to be any bug in Clojure here. Those tests were written with particular constant values that are different, but have equal .hashCode values, to test Clojure's code generated that selects between branches in a case. In particular, these tests in control.clj fail:

;; line 386 in Clojure 1.6.0 and 1.7.0-master-SNAPSHOT as of Mar 19 2015:
    (is (== (.hashCode 1) (.hashCode 9223372039002259457N)))

;; and later on line 423 in the same file:
  (testing "test warn for hash collision"
    (should-print-err-message
     #"Performance warning, .*:\d+ - hash collision of some case test constants; if selected, those entries will be tested sequentially..*\r?\n"
     (case 1 1 :long 9223372039002259457N :big 2)))

There are other tests in the same file with the same constant 9223372039002259457N that do not fail with IBM JDKs 1.7 and 1.8, but they do not test hash collisions as they were intended to.

Some possibilities for what could be changed:

1. Pick a different pair of number other than 1 and 9223372039002259457N when running tests on IBM JDKs 1.7 and 1.8, so that the hash values do collide. For example, 33 and 9223372039002259457N.

2. skip these tests completely when running on IBM JDKs 1.7 and 1.8.



 Comments   
Comment by Alex Miller [ 20/Mar/15 4:03 AM ]

I think my preference would be to skip these tests for the ibm jdk.





[CLJ-1676] map destructuring: prevent evaluation of values in :or when they are not used/needed Created: 14/Mar/15  Updated: 30/Jul/15

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

Type: Enhancement Priority: Trivial
Reporter: Max Penet Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: destructuring

Approval: Triaged

 Description   

The name :or implies this should behave as "or" and be "lazy" but it's not the case currently.
The following gist shows the issue. :x is present in the map but we eval the default value:

(defn foo
  [{:keys [x]
    :or {x (println :set-default)}}] 
  x)
 
 
 
user> (foo {:x 1})
:set-default
1


 Comments   
Comment by Ghadi Shayban [ 15/Mar/15 2:40 PM ]

1.2 - current all behave this way, doesn't seem like a recent change.

Comment by Max Penet [ 15/Mar/15 2:55 PM ]

Right, I thought it might have been a regression, but wasn't sure at all.
It seems it would be safe to change the current behavior, I doubt it would break any ones code.





[CLJ-1673] Improve clojure.repl/dir-fn to work on namespace aliases in addition to canonical namespaces. Created: 11/Mar/15  Updated: 04/May/15

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

Type: Enhancement Priority: Minor
Reporter: Jason Whitlark Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: ft, repl

Attachments: Text File clj-1673-2.patch     Text File improve_dir.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Extend clojure.repl/dir to work with the aliases in the current namespace

After:

user=> (require '[clojure.string :as s])
nil
user=> (dir s)
blank?
capitalize
...etc

Patch: clj-1673-2.patch
Screened by: Alex Miller



 Comments   
Comment by Jason Whitlark [ 11/Mar/15 4:00 PM ]

Possible unit test, since clojure.string is aliased in the test file:

(is (= (dir-fn 'clojure.string) (dir-fn 'str)))

Comment by Alex Miller [ 29/Apr/15 2:12 PM ]

Please add a test...

Comment by Jason Whitlark [ 02/May/15 10:35 PM ]

Updated patch, tweaked dir-fn, added test.

Comment by Jason Whitlark [ 02/May/15 10:38 PM ]

Should be good to go. I removed the old patch.

Comment by Alex Miller [ 04/May/15 4:38 PM ]

Tweaked patch just to remove errant blank line, otherwise same.





[CLJ-1665] take-nth transducer could be faster without rem Created: 20/Feb/15  Updated: 20/Feb/15

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

Type: Enhancement Priority: Major
Reporter: Steve Miner Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: performance
Environment:

Mac OS X 10.10.2, JDK 1.8.0_31


Attachments: Text File CLJ-1665-faster-take-nth-transducer-without-rem.patch    
Patch: Code
Approval: Triaged

 Description   

The take-nth transducer is calling rem on each index, which is relatively expensive compared to a zero? test. It could just count down from N instead as the step size is fixed.



 Comments   
Comment by Steve Miner [ 20/Feb/15 12:34 PM ]

Patch attached. It's about 25% faster on a simple test like:

(time (transduce (take-nth 13) + (range 1e7)))
Comment by Steve Miner [ 20/Feb/15 12:41 PM ]

I didn't worry about (take-nth 0) case, but my patch does give a different result. The current implementation gets a divide by zero error (from rem). My patched version returns just the first element once. The regular collection version returns an infinite sequence of the first element. I doubt anyone expects a sensible answer from the 0 case so I didn't try to do anything special with it.

Comment by Michael Blume [ 20/Feb/15 12:55 PM ]

Nice =)

I would say that the transducer version really ought to match the collection version as closely as possible, but I don't think there's actually a way to write a transducer that transforms a finite sequence into an infinite sequence, so no luck there.

Maybe while we're at it we should change both the transducer and the collection arities to throw on zero?





[CLJ-1656] Unroll assoc and assoc! for small numbers of arguments Created: 06/Feb/15  Updated: 29/Apr/15

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: Major
Reporter: Tom Crayford Assignee: Unassigned
Resolution: Unresolved Votes: 5
Labels: performance

Attachments: File assoc.diff     Text File assoc-gen-test.patch     Text File CLJ-1656-v1.patch     Text File CLJ-1656-v2.patch     Text File CLJ-1656-v3.patch     Text File CLJ-1656-v4.patch     Text File CLJ-1656-v5.patch     Text File CLJ-1656-v6.patch     Text File CLJ-1656-v7.patch     File cpuinfo     File javaversion     File output     File uname    
Patch: Code and Test
Approval: Triaged

 Description   

Whilst doing performance work recently, I discovered that unrolling to single assoc calls were significantly faster than using multiple keys (~10% for my particular application). Zachary Tellman then pointed out that clojure.core doesn't unroll assoc at all, even for the case of relatively low numbers of keys.

We already unroll other performance critical functions that call things via `apply`, e.g. `update` https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj#L5914, but `assoc` (which is, I think in the critical path for quite a bunch of applications and libraries), would likely benefit from this.

I have not yet developed patches for this, but I did some standalone benchmarking work:

https://github.com/yeller/unrolling-assoc-benchmarks

benchmark results:

code: https://github.com/yeller/unrolling-assoc-benchmarks/blob/master/src/bench_assoc_unrolling.clj

  1 2 3 4
empty array map (not unrolled) 23ns 93ns 156ns 224ns
empty array map (unrolled assoc) N/A 51ns 80ns 110ns
         
20 element persistent hashmap (not unrolled) 190ns 313ns 551ns 651ns
20 element persistent hashmap (unrolled assoc) N/A 250ns 433ns 524ns
         
record (not unrolled) 12ns 72ns 105ns 182ns
record (unrolled assoc) N/A 21ns 28ns 41ns

Each measurement was made in a separate JVM, to avoid JIT path dependence.

Benchmarks were ran on a commodity server (8 cpus, 32gb ram), with ubuntu 12.04 and a recent release of Java 8. Attached are `cpuinfo`, `uname` and `java -version` output.

Relatively standard JVM production flags were enabled, and care was taken to disable leiningen's startup time optimizations (which disable many of the JIT optimizations).

Benchmarks can be run by cloning the repository, and running `script/bench`

There's one outstanding question for this patch: How far should we unroll these calls? `update` (which is unrolled in the 1.7 alphas) is unrolled to 3 arguments. Adding more unrolling isn't difficult, but it does impact the readability of assoc.

Patch: CLJ-1656-v5.patch



 Comments   
Comment by Tom Crayford [ 09/Feb/15 12:01 PM ]

Ok, attached `assoc.diff`, which unrolls this to a single level more than the current code (so supporting two key/value pairs without recursion). The code's going to get pretty complex in the case with more than the unrolled number of keys if we continue on this way, so I'm unsure if this is a good approach, but the performance benefits seem very compelling.

Comment by Michael Blume [ 09/Feb/15 3:35 PM ]

Since the unroll comes out kind of hairy, why not have a macro write it for us?

Comment by Michael Blume [ 09/Feb/15 4:03 PM ]

Patch v2 includes assoc!

Comment by Tom Crayford [ 09/Feb/15 5:01 PM ]

I benchmarked conj with similar unrolling, across a relatively wide range of datatypes from core (lists, sets, vectors, each one empty and then again with 20 elements):

  1 2 3 4
empty vector (not unrolled) 19ns 57ns 114ns 126ns
empty vector (unrolled conj) N/A 44ns 67ns 91ns
         
20 element vector (not unrolled) 27.35ns 69ns 111ns 107ns
20 element vector (unrolled conj) N/A 54ns 79ns 104ns
         
empty list (not unrolled) 7ns 28ns 53ns 51ns
empty list (unrolled conj) N/A 15ns 20ns 26ns
         
twenty element list (not unrolled) 8.9ns 26ns 49ns 49ns
twenty element list (unrolled) N/A 15ns 19ns 30ns
         
empty set (not unrolled) 64ns 170ns 286ns 290ns
empty set (unrolled) N/A 154ns 249ns 350ns
         
twenty element set (not unrolled) 33ns 81ns 132ns 130ns
twenty element set (unrolled) N/A 69ns 108ns 139ns

Benchmarks were run on the same machine as before. There's a less clear benefit here, except for lists, where the overhead of creating seqs and recursing seems to be clearly dominating the cost of actually doing the conj (which makes sense - conj on any element list should be a very cheap operation). Raw benchmark output is here: https://gist.github.com/tcrayford/51a3cd24b8b0a8b7fd74

Comment by Tom Crayford [ 09/Feb/15 5:04 PM ]

Michael Blume: I like those patches! They read far nicer to me than my original patch. Did you check if any of those macro generated methods blew Hotspot's hot code inlining limit? (it's 235 bytecodes). That'd be my only worry with using macros here - it's easy to generate code that defeats the inliner.

Comment by Michael Blume [ 09/Feb/15 5:57 PM ]

Thanks! This is new for me, so I might be doing the wrong thing, but I just ran nodisassemble over both definitions and the "instruction numbers" next to each line go up to 219 for the varargs arity assoc and up to 251 for assoc!, so, assuming I'm looking at the right thing, maybe that one needs to have an arity taken off? If I remove the highest arity I get 232 for varargs which is just under the line.

I guess alternatively we could call assoc! instead of assoc!* in the varargs arity, which removes a lot of code – in that case it's 176 for varargs and 149 for six pairs.

Comment by Michael Blume [ 09/Feb/15 6:01 PM ]

Gah, I forgot to include coll in the varargs call to assoc!

which reminds me that this patch needs tests.

Comment by Michael Blume [ 09/Feb/15 10:27 PM ]

OK, this has some fixes I made after examining the disassembled output. There's a change to the assoc!* macro to be sure it type-hints correctly – I'm honestly not sure why it didn't type-hint properly before, but it does now. Also, I changed the call to assoc! rolling up the first six entries at the top of the varargs version from a macro call to a function call so it'd fit within the 251 inlineable bytecodes. (This, again, is assuming I'm reading the output correctly).

Comment by Tom Crayford [ 10/Feb/15 6:38 AM ]

Michael: Wanna push a branch with these patches to clojars or something? Then I can rerun the benchmarks with the exact code in the patches.

Comment by Michael Blume [ 10/Feb/15 2:36 PM ]

Hmm, not sure I know how to do that – here's a branch on github though https://github.com/MichaelBlume/clojure/tree/unroll-assoc

Comment by Michael Blume [ 12/Feb/15 1:12 PM ]

v5 marks the helper macros private.

Comment by Tom Crayford [ 13/Feb/15 4:11 AM ]

Michael: was that branch just based off clojure/clojure master? I tried running benchmarks off it, but ran into undefined var errors when building this code (which doesn't happen with alpha5):

(Retrieving com/yellerapp/clojure-unrolled-assoc/1.7.0-unrollassoc-SNAPSHOT/clojure-unrolled-assoc-1.7.0-unrollassoc-20150213.092242-1.pom from clojars)
(Retrieving com/yellerapp/clojure-unrolled-assoc/1.7.0-unrollassoc-SNAPSHOT/clojure-unrolled-assoc-1.7.0-unrollassoc-20150213.092242-1.jar from clojars)
(Retrieving org/clojure/clojure/1.3.0/clojure-1.3.0.jar from central)
Exception in thread "main" java.lang.RuntimeException: Unable to resolve symbol: bench in this context, compiling:(bench_assoc_unrolling.clj:5)
at clojure.lang.Compiler.analyze(Compiler.java:6235)
at clojure.lang.Compiler.analyze(Compiler.java:6177)
at clojure.lang.Compiler$InvokeExpr.parse(Compiler.java:3452)
at clojure.lang.Compiler.analyzeSeq(Compiler.java:6411)
at clojure.lang.Compiler.analyze(Compiler.java:6216)
at clojure.lang.Compiler.analyze(Compiler.java:6177)
at clojure.lang.Compiler$BodyExpr$Parser.parse(Compiler.java:5572)
at clojure.lang.Compiler$FnMethod.parse(Compiler.java:5008)

Comment by Michael Blume [ 23/Feb/15 5:08 PM ]

Ok, how are you building? Why the strange clojure group?

Comment by Michael Blume [ 23/Feb/15 5:09 PM ]

The existing version of assoc does runtime checking that an even number of varargs are passed in, but assoc! does not. Do we want to preserve this behavior or do checks in both?

Comment by Michael Blume [ 23/Feb/15 6:00 PM ]

Also, I'm curious how relevant inlining is here – does HotSpot inlining actually work with Var invocation when there's a getRootBinding step in the way?

Comment by Alex Miller [ 23/Feb/15 7:59 PM ]

Yes, inlining works through var invocation.

Comment by Tom Crayford [ 16/Mar/15 7:05 AM ]

Michael,

That group is just an uploaded version of clojure master with your patches applied, built in just the same way as before (you should be able to check out the repo and replicate).

Comment by Alex Miller [ 29/Apr/15 1:44 PM ]

The patch CLJ-1656-v5.patch doesn't seem to do anything with the old version of assoc (in core.clj around line 179)?

The new one needs to have the arglists and other stuff like that. I'm not sure about the macro/private vars in there either. Did you try leveraging RT.assocN() with a vector?

Are there existing tests in the test suite for assoc with N pairs?

Comment by Michael Blume [ 29/Apr/15 8:46 PM ]

The dependencies in clojure.core were such that assoc needed to be defined well before syntax-quoting, so I just let it be defined twice, once slower, once faster. I'll put up a patch with arglists. Does it need an arglist for every new arity, or are the existing arglists enough? (I'm afraid I'm not 100% solid on what the arglists metadata does) There is an annoying lack of existing tests of assoc. I have a generative test in my tree because that seemed more fun than writing cases for all the different arities. I can post it if it seems useful, it might be overkill though.

Comment by Michael Blume [ 29/Apr/15 9:50 PM ]

Here's the test patch I mentioned, it's even more overkill than I remembered

Comment by Michael Blume [ 29/Apr/15 10:01 PM ]

There, code and test.

This also checks that assoc! is passed an even number of kvs in the varargs case, which is the behavior of assoc. The test verifies that both assoc and assoc! throw for odd arg count.

Comment by Alex Miller [ 29/Apr/15 11:10 PM ]

The existing arglist is fine - it just overrides the generated one for doc purposes.

Did you try any of the RT.assocN() stuff?

I guess another question I have is whether people actually do this enough that it matters?





[CLJ-1654] Reuse seq in some Created: 04/Feb/15  Updated: 29/Apr/15

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

Type: Enhancement Priority: Trivial
Reporter: Gijs Stuurman Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: ft, performance

Attachments: Text File 0000-reuse-seq-in-some.patch    
Patch: Code
Approval: Triaged

 Description   

By using when-let at most two seq constructions can be avoided per invocation of some.

Screened by: Alex Miller



 Comments   
Comment by Ghadi Shayban [ 04/Feb/15 12:11 PM ]

This is similar to the tweak to dorun/doall in CLJ-1515. It is a good benefit when a collection doesn't cache its seq





[CLJ-1653] str of an empty list is not "()" Created: 02/Feb/15  Updated: 29/Apr/15

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

Type: Enhancement Priority: Minor
Reporter: Steve Miner Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: collections, ft, print

Attachments: Text File clj-1653-2.patch     Text File CLJ-1653-toString-for-EmptyList.patch    
Patch: Code and Test
Approval: Triaged

 Description   

The str of an empty list is surprisingly not "()". This is inconsistent with the result for the empty map {} or empty vector (). It would be convenient if `(str ())` returned "()". The work-around is to use `pr-str`, which is arguably the "correct" thing to do. However, there doesn't seem to be any reason that Clojure couldn't return "()".

(str ())
;=> "clojure.lang.PersistentList$EmptyList@1"

(str {} [] ())
;=> "{}[]clojure.lang.PersistentList$EmptyList@1"

;; Work-around: use `pr-str` instead of `str`

(pr-str () {} [])
"() {} []"

Patch: clj-1653-2.patch

Screened by: Alex Miller



 Comments   
Comment by Steve Miner [ 02/Feb/15 3:30 PM ]

PersistentList$EmptyList should have a toString method that returns "()".

Comment by Steve Miner [ 02/Feb/15 3:45 PM ]

add toString() for EmptyList

Comment by Steve Miner [ 02/Feb/15 3:45 PM ]

patch and test for toString() method on EmptyList.

Comment by Nicola Mometto [ 02/Feb/15 4:03 PM ]

Not sure how this is different from

user=> (str (range 10))
"clojure.lang.LazySeq@9ebadac6"

pr-str works fine on both () and (range 10) btw.

Comment by Steve Miner [ 02/Feb/15 5:09 PM ]

I agree in principle that pr-str is the right thing to use. I will counter the Slippery Slope argument by invoking the Principle of Least Astonishment. My argument for the proposed patch is that () is a common value and the current behavior is inconsistent with similar empty values, {} and []. I think it would be convenient and useful, especially for beginners, to fix just this one case of the empty list. On the other hand, it's a minor issue so I won't push it.

Comment by Michael Blume [ 02/Feb/15 5:59 PM ]
user=> (str '())
"clojure.lang.PersistentList$EmptyList@1"
user=> (str '(1 2))
"(1 2)"

This really makes empty list seem like a special case.

Comment by Alex Miller [ 29/Apr/15 2:17 PM ]

Added -2 patch just to fix trailing whitespace warnings, identical otherwise.





[CLJ-1647] infinite loop in 'partition' and 'partition-all' when 'step' or 'n' is not positive Created: 20/Jan/15  Updated: 27/Jul/15

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

Type: Defect Priority: Minor
Reporter: Kevin Woram Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: checkargs, newbie

Attachments: Text File clj-1647.patch     Text File kworam-clj-1647.patch    
Patch: Code
Approval: Triaged

 Description   

If you pass a non-positive value of 'n' or 'step' to partition, you get an infinite loop. Here are a few examples:

(partition 0 [1 2 3])
(partition 1 -1 [1 2 3])

To fix this, I recommend adding 'assert-args' to the appropriate places in partition and partition-all:

(assert-args
(pos? n) "n must be positive"
(pos? step) "step must be positive" )



 Comments   
Comment by Alex Miller [ 03/Feb/15 5:34 PM ]

Also see CLJ-764

Comment by Alex Miller [ 29/Apr/15 12:02 PM ]

Needs a perf check when done.

Comment by Kevin Woram [ 16/May/15 1:58 PM ]

patch file to fix clj-1647

Comment by Kevin Woram [ 16/May/15 2:19 PM ]

Since 'n' and 'step' remain unchanged from the initial function call through all of the recursive self-calls, I only need to verify that they are positive once, on the initial call.

I therefore created functions 'internal-partition' and 'internal-partition-all' whose implementations are identical to the current versions of 'partition' and 'partition-all'.

I then added preconditions that 'step' and 'n' must be positive to the 'partition' and 'partition-all' functions, and made them call 'internal-partition' and 'internal-partition-all' respectively to do the work.

Comment by Alex Miller [ 17/May/15 8:14 AM ]

There are a lot of unrelated whitespace changes in this patch - can you supply a smaller patch with only the change at issue? Also needs tests.

Comment by Kevin Woram [ 17/May/15 2:05 PM ]

I will supply a patch file without the whitespace changes.

I know there are some existing functionality tests for 'partition' and 'partition-all' in test_clojure\sequences.clj and test_clojure\transducers.clj. I don't think I need to add more functionality tests, but I think I should add:

1. Tests that verify that non-positive 'step' and 'n' parameters are rejected.
2. Tests that show that 'partition' and 'partition-all' performance has not degraded significantly.

Could you give me some guidance on how to develop and add these tests?

Comment by Alex Miller [ 17/May/15 3:31 PM ]

You should add #1 to the patch. For #2, you can just do the timings before/after (criterium is a good tool for this) and put the results in the description.

Comment by Kevin Woram [ 22/May/15 4:04 PM ]

I have coded up the tests for #1 and taken some 'before' timings for #2 using criterium.

I have been stumped by a problem for hours now and I need to get some help. I made my changes to 'partition' and 'partition-all' in core.clj and then did 'mvn package' to build the jar. I executed 'target>java -cp clojure-1.7.0-master-SNAPSHOT.jar clojure.main' to test out my patched version of clojure interactively. The (source ...) function shows that my source changes for both 'partition' and 'partition-all' are in place. My change to 'partition-all' seems to be working but my change to 'partition' is not. As far as I can tell, they should both throw an AssertionError with the input parameters I am providing.

Any help would be greatly appreciated.

user=> (source partition)
(defn partition
"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 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."
{:added "1.0"
:static true}
([n coll]
{:pre [(pos? n)]}
(partition n n coll))
([n step coll]
{:pre [(pos? n) (pos? step)]}
(internal-partition n step coll))
([n step pad coll]
{:pre [(pos? n) (pos? step)]}
(internal-partition n step pad coll)))
nil
user=> (partition -1 [1 2 3])
()
user=> (source partition-all)
(defn partition-all
"Returns a lazy sequence of lists like partition, but may include
partitions with fewer than n items at the end. Returns a stateful
transducer when no collection is provided."
{:added "1.2"
:static true}
([^long n]
(internal-partition-all n))
([n coll]
(partition-all n n coll))
([n step coll]
{:pre [(pos? n) (pos? step)]}
(internal-partition-all n step coll)))
nil
user=> (partition-all -1 [1 2 3])
AssertionError Assert failed: (pos? n) clojure.core/partition-all (core.clj:6993)

Comment by Alex Miller [ 22/May/15 4:47 PM ]

Did you mvn clean? Or rm target?

Comment by Kevin Woram [ 24/May/15 11:46 PM ]

Yes, I did mvn clean and verified that clojure-1.7.0-master-SNAPSHOT.jar had the expected date-time stamp before doing the interactive test. I even went so far as to retrace my steps on my Macbook on the theory that maybe there was a Windows-specific build problem.

My change to partition-all works as expected but my change to partition does not. However, if I copy the result of the call to (source partition) and execute it (replacing clojure.core/partition with user/partition), user/partition works as expected. I don't understand why my change to clojure.core/partition isn't taking effect.

Comment by Andy Fingerhut [ 25/May/15 1:27 AM ]

Kevin, I do not know the history of your Clojure source tree, but if you ever ran 'ant' in it, that creates jar files in the root directory, whereas 'mvn package' creates them in the target directory. It wasn't clear from your longer comment above whether the 'java -cp ...' command you ran pointed at the one in the target directory. That may not be the cause of the issue you are seeing, but I don't yet have any guesses what else it could be.

Comment by Alex Miller [ 13/Jul/15 1:17 PM ]

What's the status of this?

Comment by Kevin Woram [ 16/Jul/15 10:20 PM ]

Alex, I moved to Seattle and took a permanent position with Microsoft recently. This has kept me very busy and I haven't been able to spend time on Clojure at all. I probably won't be able to devote time to Clojure for another month or two.

Comment by Alex Miller [ 16/Jul/15 10:46 PM ]

Thanks for the heads up.

Comment by Matthew Gilliard [ 23/Jul/15 2:51 PM ]

Kevin, Alex, I could pick this up if you like?

Comment by Alex Miller [ 23/Jul/15 8:40 PM ]

Go for it

Comment by Alex Miller [ 23/Jul/15 8:40 PM ]

Go for it

Comment by Alex Miller [ 23/Jul/15 8:40 PM ]

Go for it

Comment by Alex Miller [ 23/Jul/15 8:40 PM ]

Go for it

Comment by Alex Miller [ 23/Jul/15 8:41 PM ]

Sorry, browser fail

Comment by Kevin Woram [ 25/Jul/15 7:03 PM ]

Thanks for picking it up Matthew, I appreciate it!

Comment by Kevin Woram [ 25/Jul/15 7:03 PM ]

Thanks for picking it up Matthew, I appreciate it!

Comment by Matthew Gilliard [ 27/Jul/15 11:30 AM ]

New patch: clj-1647.patch

Includes tests, fewer whitespace changes, manually thrown IAEs. I'll do some basic benchmarking soon, although I expect the overhead to be quite low as we're only checking the arguments once.

Kevin, the reason your patch was working for partition-all but not partition is that partition is defined early-ish in the bootstrapping process and the {:pre .. :post ..} maps aren't read by defn until it's enhanced later on.

Comment by Kevin Woram [ 27/Jul/15 12:10 PM ]

Thanks for solving that mystery Matthew!





[CLJ-1643] Generative test for sequence implementations Created: 15/Jan/15  Updated: 15/Jan/15

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

Type: Enhancement Priority: Major
Reporter: Michael Blume Assignee: Michael Blume
Resolution: Unresolved Votes: 0
Labels: generative-test, test

Attachments: Text File clj-1643-gen-seq-test-v1.patch    
Patch: Code and Test
Approval: Triaged

 Description   

This is an attempt to write a minimal-foreknowledge failing test for CLJ-1633. By minimal-foreknowledge, I mean a test that fails in the presence of the bug, but which one could imagine writing without intimate knowledge of the details of the bug. I suspect that looking for tests like this is a good way to find gaps in test coverage, and produce tests that will uncover novel regressions later on.

Approach: Generate a single list of operations that could be performed on a sequence, changing that sequence. Make two copies of that operation list, and insert what should be identity-preserving operations into each. Run the two lists of operations and verify that the final results are the same.

With CLJ-1633 unfixed, we get this output:

[java] Testing clojure.test-clojure.sequences
     [java]
     [java] FAIL in (seq-gentest) (sequences.clj:135)
     [java] {:acts1 (->> nil (cons :foo) (cons :foo) into-array next (apply list)),
     [java]  :acts2 (->> nil (cons :foo) (cons :foo) next),
     [java]  :result1 (:foo :foo),
     [java]  :result2 (:foo),
     [java]  :pass false}
     [java]
     [java] expected: (:result res)
     [java]   actual: false





[CLJ-1629] Improve error message when defn form omits parameter declaration Created: 29/Dec/14  Updated: 29/Dec/14

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

Type: Enhancement Priority: Major
Reporter: Sanel Zukan Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: errormsgs
Environment:

Reproducible on all platforms and all clojure versions.


Approval: Triaged

 Description   

When defn form is malformed, Clojure compiler will report meaningless error and in combination with function body, can cause really bad experience. Here is the sample:

(defn foo
  "This is docstring."
  (let [i 1]
    (+ i 1)))

It will report:

IllegalArgumentException Parameter declaration "let" should be a vector  clojure.core/assert-valid-fdecl (core.clj:7123)

However, if is written:

(defn foo "bla")

error report makes more sense:

IllegalArgumentException Parameter declaration missing  clojure.core/assert-valid-fdecl (core.clj:7107)


 Comments   
Comment by Michael Blume [ 29/Dec/14 1:39 PM ]

I don't think this is really meaningless – if you replace the symbol let with a vector, say, [i], you get a perfectly valid function definition

(defn foo
  "This is docstring."
  ([i] [i 1]
    (+ i 1)))
Comment by Sanel Zukan [ 29/Dec/14 2:41 PM ]

Yes and maybe make sense for this case. But in general, the report is misleading for common defn forms (how often you will see function definitions written this way, unless you want multi-arity function) and should have the same report as for second sample; in both cases it is the same cause.





[CLJ-1624] Support get from arbitrary java.util.List data types Created: 23/Dec/14  Updated: 23/Dec/14

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

Type: Enhancement Priority: Minor
Reporter: Mike Anderson Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: interop

Attachments: File clj-1624.diff    
Patch: Code
Approval: Triaged

 Description   

Currently "get", "get-in" and related functions in clojure.core work on Clojure vectors, maps and Java arrays, but do not work on instances of java.util.List

(def al (java.util.Arrays/asList (object-array [1 2 3 4])))
(get al 2)
=> nil

This makes it inconvenient to work with nested structures of Java objects that could otherwise be viewed as similar to nested Clojure data structures.

This is also inconsistent with other clojure.core functions that do support arbitrary java.util.List instances (e.g. "nth" and "count")

With a small change to RT.java, it is possible to allow core functions to operate on arbitrary instances of java.util.List. There does not appear to be any significant downside to this change (it is not on the fast path so will not affect regular ILookup or Map checks).



 Comments   
Comment by Mike Anderson [ 23/Dec/14 12:31 AM ]

Patch for CLJ-1624





[CLJ-1613] :or defaults should refer to enclosing scope in map destructuring Created: 12/Dec/14  Updated: 30/Jul/15

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

Type: Enhancement Priority: Minor
Reporter: Michał Marczyk Assignee: Michał Marczyk
Resolution: Unresolved Votes: 1
Labels: None

Attachments: Text File 0001-CLJ-1613-evaluate-or-defaults-in-enclosing-scope-in-.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Michael Blume noticed that :or defaults can depend on the values of other keys, see https://groups.google.com/d/msg/clojure/6kOhpPOpHWM/ITjWwQFS_VQJ

Michael's Gist https://gist.github.com/MichaelBlume/4891dafdd31f0dcbc727 displays a case where an associative form involving :keys and :or compiles or not depending on the order of symbols in :keys. By tweaking that case one can arrive at expressions which always compile, but produce different values depending on :keys:

(let [foo 1
       bar 2
       {:keys [bar foo]
        :or {foo 3 bar (inc foo)}} {}]
  {:foo foo :bar bar})
;= {:foo 3, :bar 4}

(let [foo 1
      bar 2
      {:keys [foo bar]
       :or {foo 3 bar (inc foo)}} {}]
  {:foo foo :bar bar})
;= {:foo 3, :bar 2}

I believe that the most natural solution is to demand that :or defaults be evaluated in an enclosing scope where none of the destructuring-introduced locals are present. This approach is taken by the 0001 patch.



 Comments   
Comment by Michael Blume [ 12/Dec/14 2:27 AM ]

I suspect that this is the right thing to do but I think it's important to note that this will break existing code https://github.com/ngrunwald/ring-middleware-format/blob/master/src/ring/middleware/format_params.clj#L214

Comment by Michael Blume [ 06/Apr/15 4:43 PM ]

Update on my previous comment – ring-middleware-params has updated so that it doesn't depend on this behavior. I think we should definitely merge this patch so no one else depends on it.

Comment by Max Penet [ 08/Apr/15 10:46 AM ]

Since this involves :or keys evaluation, this might be worth checking if this should/could have an impact on http://dev.clojure.org/jira/browse/CLJ-1676 as well.

Comment by Stuart Halloway [ 30/Jul/15 11:11 AM ]

This is a behavior change, the docs do not promise the requested behavior and existing code may depend on the current behavior.

Comment by Andy Fingerhut [ 30/Jul/15 12:47 PM ]

Isn't this a case where if existing code works, it works by accident of the seq order of an unordered map? If so, any code that depends upon the existing behavior sometimes breaks, sometimes does not break, when the Clojure seq order on maps changes, which occurred Clojure 1.5.1 to Clojure 1.6.0, and again from 1.6.0 to 1.7.0.

Comment by Michael Blume [ 30/Jul/15 1:08 PM ]

Yes, it does, and I've seen existing code break due to those changes, hence the discussion that lead to this ticket.





[CLJ-1611] clojure.java.io/pushback-reader Created: 08/Dec/14  Updated: 26/May/15

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

Type: Enhancement Priority: Major
Reporter: Phill Wolf Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: io, reader

Attachments: Text File drupp-clj-1611-2.patch     Text File drupp-clj-1611.patch    
Patch: Code and Test
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-1607] docstring for clojure.core/counted? should be more specific Created: 29/Nov/14  Updated: 26/May/15

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

Type: Enhancement Priority: Minor
Reporter: Gary Fredericks Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: docstring

Attachments: Text File CLJ-1607-p1.patch    
Patch: Code
Approval: Triaged

 Description   

The docstring for counted? currently says:

Returns true if coll implements count in constant time

This tempts the user into thinking they can use this function to determine whether or not calling count on any collection is a constant-time operation, when in fact it only reflects whether or not an object implements the clojure.lang.Counted interface. Since count special-cases a handful of platform types, there are common cases such as Arrays and Strings that are constant time but will return false from counted?.

Proposed:

Returns true if coll, a Clojure collection, implements count in constant time. Note that this function will return false for host types even if the count function can return their size in constant time (as with arrays and strings).



 Comments   
Comment by Gary Fredericks [ 29/Nov/14 9:01 AM ]

Attached CLJ-1607-p1.patch with my first draft of a better docstring.

Comment by Gary Fredericks [ 29/Nov/14 9:08 AM ]

What would be the most accurate language to describe the exceptions? I used "some collections" in the first patch but perhaps "native collections" or "host collections" would be more helpful?

Comment by Alex Miller [ 29/Nov/14 9:44 AM ]

While I understand where you're coming from, I think the intent of "counted?" is not to answer the question "is this thing countable in constant time" for all possible types, but specifically for collections that participate in the Clojure collection library. This includes both internal collections like PHM, PHS, PV, etc but also external collections that mark their capabilities using those interfaces.

I believe count handles more cases than just collections that are counted in constant time (like seqs) so is not intended to be symmetric with counted?.

Comment by Gary Fredericks [ 29/Nov/14 9:55 AM ]

Sure, I wasn't suggesting changing what the function does – just changing the docstring to make it less likely to be misleading.

Comment by Gary Fredericks [ 29/Nov/14 10:00 AM ]

What about this sort of wording?

Returns true if coll, a Clojure collection, implements count in constant time.
Note that this function will return false for host types even if the count 
function can return their size in constant time (as with arrays and strings).
Comment by Alex Miller [ 30/Nov/14 9:52 PM ]

I think it's unlikely to pass vetting, but that's just my guess.

Comment by Gary Fredericks [ 01/Dec/14 8:53 AM ]

I'm trying to figure out where the disagreement is here; are you arguing any of these points, or something different?

  1. The docstring is not likely to confuse people by making them think it gives meaningful responses for host collections
  2. It's not a problem for us to solve if the docstring confuses people
  3. It is a problem we should solve, but the changes I've suggested are a bad solution
Comment by Alex Miller [ 01/Dec/14 9:18 AM ]

In general, the docstrings prefer concision and essence over exhaustive cases or examples. My suspicion is that the docstring says what Rich wants it to say and he would consider the points you've added to be implicit in the current docstring, and thus unnecessary. Specifically, "coll" is used pretty consistently to mean a Clojure collection (or sequence) across all of the docstrings. And there is an implicit else in the docstring that counted? will return false for things that are not Clojure collections. The words that are there (and not there) are carefully chosen.

I agree with you that more words may be necessary to describe fully what to expect from this or any other function in core. My experience from seeing Rich's response on things like this is that he may agree with that too, but he would prefer it to live somewhere outside the doc string in reference material or other sources. Not to say that we don't update docstrings, as that does happen pretty regularly; I just don't think this one will be accepted. I've asked Stu to give me a second set of eyes too.

Comment by Gary Fredericks [ 01/Dec/14 9:36 AM ]

That was helpful detail, thanks!

Comment by Reid McKenzie [ 01/Dec/14 12:42 PM ]

I think this one is fine as-is, because the docstring for count explicitly notes "Also works on ..." which are implied not to be counted?.





[CLJ-1599] Add a reset! that returns old value Created: 24/Nov/14  Updated: 02/Mar/15

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

Type: Enhancement Priority: Major
Reporter: Steven Yi Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: atom

Attachments: File get-and-set.diff    
Patch: Code
Approval: Triaged

 Description   

DESCRIPTION

This patch adds the equivalent of reset!, here called get-and-set!, to core to allow getting the last value from an atom and setting it to a new value. This is useful for atomically draining an atom of its value and setting to a new value. The implementation delegates to Java's AtomicReference.getAndSet().

The equivalent operation in Clojure code would be:

(defn get-and-set! [atm newv]
(loop [oldv @atm]
(if (compare-and-set! atm oldv newv)
oldv
(recur @atm))))

This is close to a 1:1 translation of the Java code in sun.misc.Unsafe's getAndSetObject, used by AtomicReference (as of current JDK9 source code).

APPLICATIONS

  • User may want to check if an operation has occurred before by using an atom as a flag. I.e.,

(def has-run-once (atom false))
...
(when-not (get-and-set! has-run-once true)
(do something))

  • User may want to use an atom similarly to a java.util.concurrent.LinkedTransferQueue, for the case of pairing up adds by writers and drainTo by readers:

Thread 1: (swap! atm conj item1)
Thread 2: (swap! atm conj item2)
Thread 3: (let [new-vals (get-and-set! atm [])]
(do-something new-vals))

ALTERNATIVES

  • For case of atom as flag, user can use existing compare-and-set!:

(def has-run-once (atom false))
...
(when-not (compare-and-set! has-run-once false true)
(do something))

Argument: get-and-set! is a little clearer in intent as it is using the value of the atom, rather than the success of the cas operation. Also, this would not be applicable to situations where the value stored is not a boolean.

  • User can just go ahead and use LinkedTransferQueue.

Argument: User not fluent in Java may not be readily able to use this.

==

Argument for: This seems like a sufficiently primitive operation to include in core for atoms. I am unsure of the rationale, but assume it was vetted to include into Java's AtomicReference for a reason. Also, if users are using atoms and have this available, they are less likely to try to do this incorrectly, such as:

(let [vals @some-atom]
(reset! some-atom [])
(do-something-with vals))

Argument against: This may not be sufficiently primitive enough to include in core. Users have a workaround to implement the get-and-set! operation in user-code as given above.

Note: This request is similar to CLJ-1454 (http://dev.clojure.org/jira/browse/CLJ-1454), but differs in that this is not a swap! operation that accepts an IFn argument. Also, I looked to add a test in test/clojure/test_clojure/atoms.clj, but saw that the other operations weren't tested. (I assume this is due to the other operations delegating to AtomicReference and hence not deemed test-worthy.)



 Comments   
Comment by Michael Blume [ 02/Mar/15 5:03 PM ]

I tend to wind up inevitably adding this to my projects, be nice to have it in core

Comment by Alex Miller [ 02/Mar/15 7:27 PM ]

So CLJ-1454 is swap! and return old and CLJ-1599 is reset! and return old?

Comment by Steven Yi [ 02/Mar/15 7:48 PM ]

Yes, I think that's an accurate interpretation of the two tickets.





[CLJ-1598] Make if forms compile directly to the appropriate branch expression if the test is a literal Created: 24/Nov/14  Updated: 26/May/15

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

Type: Enhancement Priority: Minor
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 2
Labels: compiler, performance, primitives

Attachments: Text File 0001-if-test-expr-of-an-if-statement-is-a-literal-don-t-e.patch    
Patch: Code
Approval: Triaged

 Description   

This allows expressions like `(cond (some-expr) 1 :else 2)` to be eligible for unboxed use, which is not currently possible since the cond macro always ends up with a nil else branch that the compiler currently takes into account.

With the attached patch, the trailing (if :else 2 nil) in the macroexpansion will be treated as 2 by the Compiler, thus allowing the unboxed usage of the cond expression.






[CLJ-1591] Symbol not being bound in namespace when name clashes with clojure.core Created: 14/Nov/14  Updated: 28/Dec/14

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

Type: Defect Priority: Minor
Reporter: Mike Anderson Assignee: Unassigned
Resolution: Unresolved Votes: 3
Labels: None

Approval: Triaged

 Description   

The following code fails (both in 1.6 and latest 1.7-alpha4):

user=> (ns foo)
nil
foo=>  (def inc inc)
WARNING: inc already refers to: #'clojure.core/inc in namespace: foo, being replaced by: #'foo/inc
#'foo/inc

;; Note inc is unbound at this point, which causes the exception below
foo=> inc
#<Unbound Unbound: #'foo/inc>
foo=> (ns bar)
nil
bar=> (require ['foo :refer ['inc]])
WARNING: inc already refers to: #'clojure.core/inc in namespace: bar, being replaced by: #'foo/inc
nil
bar=> (inc 8)

IllegalStateException Attempting to call unbound fn: #'foo/inc  clojure.lang.Var$Unbound.throwArity (Var.java:43)

Further investigation shows that foo/inc is unbound:

foo/inc
=> #<Unbound Unbound: #'foo/inc>

Further investigation also shows that replacing the (def inc inc) with almost anything else, e.g. (def inc dec), (def inc clojure.core/inc), or (def inc (fn [n] (+ n 1))), causes no exception (but the warnings remain).

I would expect:
a) foo/inc should be bound and have the same value as clojure.core/inc
b) No error when requiring foo/inc
c) bar/inc should be bound to foo/inc



 Comments   
Comment by Nicola Mometto [ 14/Nov/14 10:04 PM ]

The second error should be expected, the right syntax should be (require ['foo :refer ['inc]]) (note the leading quote before inc)

Comment by Mike Anderson [ 14/Nov/14 10:20 PM ]

Thanks for the catch Nicola - I've edited the description. Still get the same error however (just with a slightly different message)

Comment by Alex Miller [ 14/Nov/14 10:22 PM ]

See comment...

Comment by Mike Anderson [ 14/Nov/14 10:24 PM ]

@Alex what comment? Note that the error still occurs even with the right syntax....

Comment by Mike Anderson [ 14/Nov/14 10:26 PM ]

Appears to have been closed prematurely

Comment by Alex Miller [ 14/Nov/14 10:39 PM ]

I can't reproduce with the correct syntax:

Clojure 1.7.0-master-SNAPSHOT
user=> (ns foo)
nil
foo=> (def inc inc)
WARNING: inc already refers to: #'clojure.core/inc in namespace: foo, being replaced by: #'foo/inc
#'foo/inc
foo=> (ns bar)
nil
bar=> (require ['foo :refer ['inc]])
WARNING: inc already refers to: #'clojure.core/inc in namespace: bar, being replaced by: #'foo/inc
nil
Comment by Mike Anderson [ 14/Nov/14 10:55 PM ]

The problem is that the var is still unbound and causes e.g. the following error:

=> (foo/inc 8)
IllegalStateException Attempting to call unbound fn: #'foo/inc clojure.lang.Var$Unbound.throwArity (Var.java:43)

I don't think that should be expected - or am I missing something?

Comment by Alex Miller [ 14/Nov/14 10:57 PM ]

Ah, will take a look. But not right now.

Comment by Andy Fingerhut [ 15/Nov/14 1:09 PM ]

Updated the description with a few more details. The exception goes away if you do (def inc (fn [n] (+ n 1))) instead of (def inc inc), for example. The warnings remain.

Comment by Tom Crayford [ 20/Nov/14 11:07 AM ]

Unsure if this is the same issue (I think it might be?), but I reproduced the exact same error message with AOT compilation involved:

reproduced in this git repository: https://github.com/yeller/compiler_update_not_referenced_bug

clone it, run `lein do clean, uberjar, test`, and that error message will show up every time for me

Comment by Andy Fingerhut [ 20/Nov/14 5:43 PM ]

Mike, I think replacing (def inc inc) in your example with (def inc clojure.core/inc) should be considered as a reasonable workaround for this issue, unless you have some use case where you need to def inc to something that is not in clojure.core (and if so, why?)

The reason (def inc inc) behaves this way is, if not absolutely necessary, at least commonly used in Clojure programs to define recursive functions, e.g. (defn fib [n] (if (<= n 1) 1 (+ (fib (dec n)) (fib (- n 2))))), so that the occurrences of fib in the body are resolved to the fib being defined.

Comment by Alex Miller [ 22/Nov/14 9:05 AM ]

Moving to 1.7 until I can look at this more deeply.

Comment by Mike Anderson [ 23/Nov/14 6:08 PM ]

Andy - yes the workaround is fine for me right now.

I don't think this is an urgent issue but it may be exposing a subtle complexity regarding assumptions about the state of the namespace at different times. Perhaps the semantics should be something like:

  • The def statement itself should be run before the var is interned. e.g. (def inc (inc 5)) should result in (def inc 6)
  • Anything complied / deferred to run after completion of the def statement should use the new var (i.e. the new var should be referenced by fns, lazy sequences etc.)
Comment by Andy Fingerhut [ 23/Nov/14 6:36 PM ]

I'm not sure what your proposal means in a case like this:

(def inc (fn [x] (inc x)))

Is the second inc to be interpreted/resolved before or after the new inc is created? Because it is (fn ...) it should be the after-behavior? What else besides fn should cause the after-behavior, rather than the before-behavior?

Even more fun (not saying that people often write code like this, but the compiler can handle it today):

(def inc (if (> (inc y) 5)
           (fn [x] (inc x))
           (fn [x] (dec x))))

I think the current compiler behavior of 'in the body of a def, the def'd symbol always refers to the new var, not any earlier def'd vars' is fairly straightforward to explain.

Comment by Tom Crayford [ 23/Nov/14 9:15 PM ]

Should I file the AOT issue reproduced in that thing as a new issue?

Comment by Andy Fingerhut [ 24/Nov/14 5:16 PM ]

Tom: Alex Miller or another screener would be best to say whether the AOT issue should be a separate ticket, but my best guess would be "go for it". I tried to look at the link you gave but it seems not to point to anything. Could you double-check that link?

Comment by Tom Crayford [ 24/Nov/14 6:48 PM ]

Andy,

Great. I'll write one up tomorrow sometime. I accidentally left that repo as private, should be visible now.

Comment by Andy Fingerhut [ 24/Nov/14 8:11 PM ]

This comment is really most relevant for ticket CLJ-1604, where it has been copied:

Tom, looked at your project. Thanks for that. It appears not to have anything like (def inc inc) in it. It throws exception during test step of 'lein do clean, uberjar, test' consistently for me, too, but compiles with only warnings and passes tests with 'lein do clean, test'. I have more test results showing in which Clojure versions these results change. To summarize, the changes to Clojure that appear to make the biggest difference in the results are below (these should be added to the new ticket you create – you are welcome to do so):

Clojure 1.6.0, 1.7.0-alpha1, and later changes up through the commit with description "CLJ-1378: Allows FnExpr to override its reported class with a type hint": No errors or warnings for either lein command above.

Next commit with description "Add clojure.core/update, like update-in but takes a single key" that adds clojure.core/update: 'lein do clean, test' is fine, but 'lein do clean, uberjar' throws exception during compilation, probably due to CLJ-1241.

Next commit with description "fix CLJ-1241": 'lein do clean, test' and 'lein do clean, uberjar' give warnings about clojure.core/update, but no errors or exceptions. 'lein do clean, uberjar, test' throws exception during test step that is same as the one I see with Clojure 1.7.0-alpha4. Debug prints of values of clojure.core/update and int-map/update (in data.int-map and in Tom's namespace compiler-update-not-referenced-bug.core) show things look fine when printed inside data.int-map, and in Tom's namespace when not doing the uberjar, but when doing the uberjar, test, int-map/update is unbound in Tom's namespace.

In case it makes a difference, my testing was done with Mac OS X 10.9.5, Leiningen 2.5.0 on Java 1.7.0_45 Java HotSpot(TM) 64-Bit Server VM

Comment by Nicola Mometto [ 25/Nov/14 3:44 PM ]

Tom, I've opened a ticket with a patch fixing the AOT issue: http://dev.clojure.org/jira/browse/CLJ-1604





[CLJ-1585] Report boxed math warning on function that boxes primitive return value Created: 11/Nov/14  Updated: 28/Dec/14

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

Type: Enhancement Priority: Minor
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: errormsgs, math

Attachments: Text File clj-1585.patch    
Patch: Code
Approval: Triaged

 Description   

With the new :warn-on-boxed (CLJ-1325), these examples do not report a boxed math warning although they each do boxing:

user=> (defn f1 [^long x] (inc x))
f1
user=> (defn f2 [x] (aget (long-array [1 2]) 0))
f2
user=> (defn f3 [x] (aget (int-array [1 2]) 0))
f3
user=> (defn f4 [^String s] (.indexOf s "a"))

Cause: emitBoxReturn has a hard-coded call to box a prim return value.

Solution: If *unchecked-math* is set to :warn-on-boxed, emit a warning on boxing of primitive numeric return types.

Patch:



 Comments   
Comment by Alex Miller [ 12/Nov/14 12:39 AM ]

Attached patch does the job, but from trying it out on some real code, it finds both problematic cases and lots of cases that could safely be ignored and/or where there is no obvious way to fix the warning. I think it may need some more tuning to reduce the rate of unfixable things a bit.





[CLJ-1579] source-fn can fail due to reading namespace-aliased keywords while in another namespace context Created: 05/Nov/14  Updated: 21/Nov/14

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

Type: Defect Priority: Minor
Reporter: Reid McKenzie Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None

Attachments: Text File 0001-Read-src-in-appropriate-ns-context.patch    
Patch: Code
Approval: Triaged

 Description   

clojure.repl/source-fn functions by using a custom reader to read a source form at the location specified by line & file metadata on a given symbol. While this works well for most things, I encountered an issue when applying source-fn to code containing keyword namespace aliases ala ::T/foo. ::T/foo is a legitimate namespace keyword in the context where it occurs, because a namespace alias to T is created in the ns header. When the keyword ::T/foo is read then, it resolves to :my-other.ns/foo as one would expect because ns has the appropriate alias. However when attempting to read source via clojure.repl/source-fn, ns may no longer be the original read context of the indicated form thus leading to the erroneous exception java.lang.RuntimeException: Invalid token: ::T/foo.

The solution is that the reading operation of clojure.repl/source-fn must be wrapped in (binding [*ns* (.ns v)] ...) so that source reading will take place in the original load reading context thus preventing this error.

A patched equivalent function exists here, https://github.com/clojure-grimoire/lein-grim/blob/master/src/grimoire/doc.clj#L50-L74, and I will submit a patch against 1.6.0 in the morning.






[CLJ-1567] Unused local in clojure.core/condp definition Created: 17/Oct/14  Updated: 20/Oct/14

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

Type: Enhancement Priority: Trivial
Reporter: Jan Krajicek Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: ft, newbie

Attachments: Text File 0001-Remove-unused-local-in-clojure.core-condp.patch    
Patch: Code
Approval: Triaged

 Description   

The 'gres' local in clojure.core/condp definition is not used:

https://github.com/clojure/clojure/blob/eccff113e7d68411d60f7204711ab71027dc5356/src/clj/clojure/core.clj#L6071

Screened by: Alex Miller



 Comments   
Comment by Bozhidar Batsov [ 19/Oct/14 12:07 AM ]

Patch added.





[CLJ-1545] Add unchecked-divide, unchecked-remainder Created: 02/Oct/14  Updated: 06/Oct/14

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

Type: Enhancement Priority: Major
Reporter: Andy Fingerhut Assignee: Colin Taylor
Resolution: Unresolved Votes: 0
Labels: math, newbie

Attachments: File CLJ-1545-2.diff     File CLJ-1545.diff    
Patch: Code and Test
Approval: Triaged

 Description   

This appears like it might be an oversight that these are missing. There are unchecked-divide-int and unchecked-remainder-int functions, but not equivalents for longs, even though there are equivalents for longs for every other unchecked operation. The JVM has bytecodes for long division and remainder.

The Clojure documentation in the section "Support for Java Primitives" on page http://clojure.org/java_interop has links for unchecked-divide and unchecked-remainder, but since they don't exist in Clojure, the API link targets don't exist.

It seems like a good idea to either add these to Clojure, or remove them from the documentation.



 Comments   
Comment by Colin Taylor [ 03/Oct/14 6:17 PM ]

Having a go at this.

Comment by Colin Taylor [ 04/Oct/14 6:02 AM ]
  • Added tests for unchecked-divide-int and unchecked-remainder-int too.
  • Unchecked fns only support binary arity and will throw CompilerException(ArityException)s where checked will not.
  • Is there any value to (int,long) (long,int) overrides for java interop cases e.g. using java collections from Clojure in high perf code?
Comment by Alex Miller [ 04/Oct/14 9:13 AM ]

Thanks for taking this on Colin!

1) When I apply the patch (git apply CLJ-1545.diff), I get a bunch of whitespace errors which will need to be cleaned up but also the patch seems to fail to apply at all on the changes in test/clojure/test_clojure/numbers.clj. It looks like perhaps the diff is just not the right diff format. You might want to check out the instructions at http://dev.clojure.org/display/community/Developing+Patches about using git format-patch.

2) If you could put a more useful git commit message, that would be helpful. Something like "CLJ-1545 Adds missing unchecked-divide and unchecked-remainder for primitive longs."

Thanks!

Comment by Colin Taylor [ 04/Oct/14 4:47 PM ]

Uggh, sorry Alex.

New patch with better commit message.

Comment by Alex Miller [ 04/Oct/14 7:24 PM ]

The patch format looks better. Pulling out farther to the ticket itself, afaict Clojure will already use the right byteocode for checked or unchecked so this may not even be needed?

If I compile (without the patch):

(defn foo-div ^long [^long a ^long b]
  (quot a b))

then the bytecode for that fn is:

public final long invokePrim(long, long);
    Code:
       0: lload_1
       1: lload_3
       2: ldiv
       3: lreturn

similarly, quot of two longs yields the same code but with lrem. I think patch has no net effect on the resulting bytecode?

Comment by Andy Fingerhut [ 04/Oct/14 7:42 PM ]

Alex, did you do the testing in your previous comment with *unchecked-math* true or false? If false, then I would think that if CLJ-1254 is judged a bug, then the behavior you saw is a bug, too, that misses the same corner case.

Comment by Alex Miller [ 04/Oct/14 10:19 PM ]

The current results are the same with either unchecked-math setting, but I see your point.

Refreshing my memory of the (/ Long/MIN_VALUE -1) case, I think you're right. The (new) unchecked-divide / remainder should do what the current (checked) forms do and the regular division and remainder cases should be making the overflow check. I think CLJ-1254 should cover the quot changes.

Comment by Colin Taylor [ 04/Oct/14 10:19 PM ]

user=> (dotimes [_ 6] (time (dotimes [_ 50000000] (unchecked-divide 4 (System/currentTimeMillis)))))
"Elapsed time: 1806.942 msecs"
"Elapsed time: 1808.747 msecs"
"Elapsed time: 1865.074 msecs"
"Elapsed time: 1802.777 msecs"
"Elapsed time: 1839.468 msecs"
"Elapsed time: 1830.61 msecs"
nil
user=> (dotimes [_ 6] (time (dotimes [_ 50000000] (/ 4 (System/currentTimeMillis)))))
"Elapsed time: 5003.598 msecs"
"Elapsed time: 4998.182 msecs"
"Elapsed time: 4941.237 msecs"
"Elapsed time: 5036.517 msecs"
"Elapsed time: 4965.867 msecs"
"Elapsed time: 4982.693 msecs"





[CLJ-1542] Docstring for deliver should describe its return value Created: 30/Sep/14  Updated: 30/Sep/14

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

Type: Enhancement Priority: Minor
Reporter: Gary Fredericks Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: docstring

Approval: Triaged

 Description   

It is presumably useful when delivering a promise to know if the delivery was successful or not (where it might be unsuccessful if it was already delivered, perhaps on another thread).

The deliver function seems to currently communicate this by returning a truthy value (the promise itself) on success and a falsy value (nil) on failure. If this is intentional, the docstring should say so so that users can comfortably rely on it.

In CLJ-1038 Rich elected for the docstring to not describe the return value; I'm not sure if that was a reluctance to fully specify the return value (promise vs nil) even if partially describing it (truthy vs falsy) would be okay.






[CLJ-1527] Clarify and align valid symbol and keyword rules for Clojure (and edn) Created: 18/Sep/14  Updated: 31/Jul/15

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: 11
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?





[CLJ-1516] Throw an exception if def name contains a dot Created: 29/Aug/14  Updated: 29/Aug/14

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

Type: Enhancement Priority: Minor
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler

Attachments: Text File 0001-throw-an-exception-on-def-names-containing-dots.patch    
Patch: Code
Approval: Triaged

 Description   

In this comment: http://dev.clojure.org/jira/browse/CLJ-1100?focusedCommentId=35510&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-35510 Rich said that Vars whose name contains a dot are not supported, but the current implementation allows their definition.
This patch makes `(def foo.bar)` throw a compile-time exception



 Comments   
Comment by Alex Miller [ 29/Aug/14 10:41 AM ]

I'm curious whether this breaks existing code in the wild.

Comment by Nicola Mometto [ 29/Aug/14 10:45 AM ]

I find this hard to believe given the current behaviour:

user=> (def a.b 1)
#'user/a.b
user=> a.b
CompilerException java.lang.ClassNotFoundException: a.b, compiling:(NO_SOURCE_PATH:0:0)

one would need to go out of his way and refer to the var namespace qualified everywhere to make it work

Comment by Nicola Mometto [ 29/Aug/14 11:03 AM ]

After a brief conversation on #clojure, I updated the patch to only throw on non-macro defs so that macros like clojure.core/.. and clojure.core.incubator/.?. will work fine





[CLJ-1509] Some clojure namespaces not AOT-compiled and included in the clojure jar Created: 20/Aug/14  Updated: 20/Aug/14

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

Type: Defect Priority: Minor
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: build

Patch: Code
Approval: Triaged

 Description   

There is a list of namespaces to AOT in build.xml and several namespaces are missing from that list, thus no .class files for those namespaces are created or included in the standard clojure jar file as part of the build.

Missing namespaces include:

  • clojure.core.reducers
  • clojure.instant
  • clojure.parallel
  • clojure.uuid

Proposal: Attached patch sorts the ns list alphabetically (for easier maintenance) and adds clojure.instant and clojure.uuid to the compiled namespaces. clojure.parallel is deprecated and requires the JSR-166 jar so was not included (perhaps it's a separate ticket to remove this). clojure.core.reducers uses a compile-time check to choose the fork/join packages to use so cannot be compiled early.

Patch: clj-1509.diff

Screened by:



 Comments   
Comment by Alex Miller [ 20/Aug/14 1:06 PM ]

Looking at this a bit further, clojure.core.reducers uses the compile-if macro to determine what version of fork/join is available so AOT-compiling this namespace would fix that decision at build time rather than runtime, so it cannot be included.





[CLJ-1493] Fast keyword intern Created: 06/Aug/14  Updated: 11/Sep/14

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

Type: Enhancement Priority: Major
Reporter: dennis zhuang Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: keywords, performance
Environment:

Mac OS X 10.9.4 / 2.6 GHz Intel Core i5 / 8 GB 1600 MHz DDR3
java version "1.7.0_17"
Java(TM) SE Runtime Environment (build 1.7.0_17-b02)
Java HotSpot(TM) 64-Bit Server VM (build 23.7-b01, mixed mode)


Attachments: File fast_keyword_intern.diff    
Patch: Code
Approval: Triaged

 Description   

Keyword's intern(Symbol) method uses recursive invocation to get a valid keyword instance.I think it can be rewrite into a 'for loop'
to reduce method invocation cost.
So i developed this patch, and make some simple benchmark.Run the following command line three times after 'ant jar':

java -Xms64m -Xmx64m -cp test:clojure.jar clojure.main -e "(time (dotimes [n 10000000] (keyword (str n))))"

Before patched:

"Elapsed time: 27343.827 msecs"
"Elapsed time: 26172.653 msecs"
"Elapsed time: 25673.764 msecs"

After patched:

"Elapsed time: 24884.142 msecs"
"Elapsed time: 23933.423 msecs"
"Elapsed time: 25382.783 msecs"

It looks the patch make keyword's intern a little more fast.

The patch is attached and test.

Thanks.

P.S. I've signed the contributor agreement, and my email is killme2008@gmail.com .



 Comments   
Comment by Alex Miller [ 07/Aug/14 9:01 AM ]

Looks intriguing (and would be a nice change imo). I ran this on a json parsing benchmark I used for the keyword changes and saw ~3% improvement.

Comment by dennis zhuang [ 07/Aug/14 9:54 PM ]

Updated the patch, remove the 'k == null' clause in for loop,it's not necessary.

Comment by Andy Fingerhut [ 11/Aug/14 1:29 AM ]

Dennis, while JIRA can handle multiple patches with the same name, it can be confusing for people discussing the patches, and for some scripts I have to evaluate them. Please consider giving the patches different names (e.g. with version numbers in them), or removing older ones if they are obsolete.

Comment by dennis zhuang [ 11/Aug/14 9:19 AM ]

Hi,andy

Thank you for reminding me.I deleted the old patch.

Comment by dennis zhuang [ 11/Sep/14 10:34 AM ]

I am glad to see it is helpful.I benchmark the patch with current master branch,it's fine too.





[CLJ-1492] PersistentQueue objects are improperly eval'd and compiled Created: 06/Aug/14  Updated: 07/Aug/14

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

Type: Defect Priority: Minor
Reporter: Jon Distad Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler
Environment:

OS X 10.9.4
java version "1.7.0_60"
Java(TM) SE Runtime Environment (build 1.7.0_60-b19)
Java HotSpot(TM) 64-Bit Server VM (build 24.60-b09, mixed mode)


Attachments: Text File 0001-Exclude-PersistentQueue-from-IPersistentList-eval-co.patch    
Patch: Code and Test
Approval: Triaged

 Description   

PersistentQueue objects do not follow the correct evaluation path in the Compiler.

The simplest case:

user=> (def q (conj clojure.lang.PersistentQueue/EMPTY 1 2 3))
#'user/q
user=> q
#<PersistentQueue clojure.lang.PersistentQueue@7861>
user=> (eval q)
CompilerException java.lang.ClassCastException: clojure.lang.PersistentQueue cannot be cast to java.util.List, compiling:(NO_SOURCE_PATH:4:1)

And you get the same exception when embedding a PersistentQueue:

user=> (eval `(fn [] ~q))
CompilerException java.lang.ClassCastException: clojure.lang.PersistentQueue cannot be cast to java.util.List, compiling:(NO_SOURCE_PATH:2:1)

Instead of the expected:

CompilerException java.lang.RuntimeException: Can't embed unreadable object in code: #<PersistentQueue clojure.lang.PersistentQueue@7861>, compiling:(NO_SOURCE_PATH:3:1)

Since PersistentQueue implements IPersistentCollection and IPersistentList, and is not called out explicitly in the compiler, it is falling into the same compile path as a list. The exception comes from the call to emitValue inside the emitConstants portion of the FnExpr emit path. PersistentQueue does not implement java.util.List and thus the cast in emitListAsObjectArray (Compiler.java:4479) throws. Implementing List would NOT, however, resolve this issue, but would mask it by causing all eval'd PersistedQueues to be compiled as PersistentLists.

The first case is resolved by adding `&& !(form instanceof PersistentQueue)` to the IPersistentCollection branch of Compiler.eval() (Compiler.java:6695-8), allowing the PersistentQueue to fall through to the ConstantExpr case in analyze (Compiler.java:6459). The embedding case is resolved by adding `&& !(value instanceof PersistentQueue)` to the IPersistentList branch in ObjExpr's emitValue (Compiler.java:4639).

This bug also precludes definition of data-readers for PersistentQueue as the read object throws an exception when it is passed to the Compiler.

The attached patch includes the two changes mentioned above, and tests for each case that illustrates the bug.

Clojure-dev thread: https://groups.google.com/forum/#!topic/clojure-dev/LDUQfqjFg9w






[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: 4
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-1488] Implement Named over Vars Created: 01/Aug/14  Updated: 28/Dec/14

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

Type: Enhancement Priority: Major
Reporter: Reid McKenzie Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None

Attachments: Text File 0001-Implement-clojure.lang.Named-over-Vars.patch    
Patch: Code
Approval: Triaged

 Description   

Vars, while a general reference structure, are used to implement bindings and have special reader and printer notation reflecting this reality. Unlike Keywords and Symbols which share the "namespace/name" notation of Vars, Vars do not implement the clojure.lang.Named interface while they print as if they were Named.

The attached patch implements Named over Vars.

Example:

user=> (name :clojure.core/conj)
"conj"
user=> (namespace :clojure.core/conj)
"clojure.core"
user=> (name 'clojure.core/conj)
"conj"
user=> (namespace 'clojure.core/conj)
"clojure.core"
user=> (name #'clojure.core/conj)
"conj"
user=> (namespace #'clojure.core/conj)
"clojure.core"
user=> (with-local-vars [x 1] (name x))
"--unnamed--"
user=> (with-local-vars [x 1] (namespace x))
nil
user=> (with-local-vars [x 1] (println x))
#<Var: --unnamed-->

This is useful for applications such as the CinC project where Vars are often taken directly as values in which context they would ideally be interchangeable with the Symbols the bound values of which they represent.



 Comments   
Comment by Nicola Mometto [ 02/Aug/14 11:42 AM ]

With this patch calling `name` on a unnamed Var will cause a NPE, I don't think this is desiderable.

Comment by Reid McKenzie [ 02/Aug/14 1:39 PM ]

I agree, however this behavior seems to be standard in Core.

Clojure 1.6.0
user=> (name nil)
NullPointerException clojure.core/name (core.clj:1518)
user=> (namespace nil)
NullPointerException clojure.core/namespace (core.clj:1526)

I'm also not convinced that the "name" or "namespace" of an unbound var is meaningful, in which case a NPE is probably acceptable.

Comment by Nicola Mometto [ 02/Aug/14 1:45 PM ]

I was not talking about unbound Vars, but about anonymous Vars, I'm assuming you miswrote.

I'd agree with you that throwing an exception could be a reasonable behaviour, except I can test for nil before calling name on it while there's no way to test whether a var is named or not, except trying to access directly the .name field which is excatly what this ticket is for.

Comment by Nicola Mometto [ 02/Aug/14 2:27 PM ]

Me and Reid have been talking about this issue over IRC, here's what's come up:

  • Vars can be either unnamed (as are Vars returned by with-local-vars) or contain both a namespace and a name part( that's the case for interned Vars)
  • there's currently no way to test for the "internedness" of a Var, so accessing either the .name or the .namespace field of the Var testing for nil is the only way to do it currently

given the above, the current patch seems unsatisfactory, here some proposed solutions:

  • make Var Named, make namespace return nil for an unnamed Var and name return "--unnamed--"
  • keep Var not implementing Named, add a "var-symbol" function returning either a namespaced symbol matching the ns+name of the Var or nil for an unnamed Var

Personally, I'd rather have the second solution implemented as I don't feel Var should be Named given that they can be unnamed and that strikes me as a contradicion

Comment by Reid McKenzie [ 02/Aug/14 3:16 PM ]

Added patches explicitly handling the unnamed var cases.

Comment by Reid McKenzie [ 02/Aug/14 3:33 PM ]

Squashed all patches into a single diff and updated attachments.





[CLJ-1483] Clarify the usage of replace(-first) with a function Created: 27/Jul/14  Updated: 29/Jul/14

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

Type: Enhancement Priority: Trivial
Reporter: Bozhidar Batsov Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: docstring, string

Attachments: Text File 0001-Clarify-the-usage-of-replace-first-with-pattern-func.patch    
Patch: Code
Approval: Triaged

 Description   

The documentation of replace and replace-first didn't feature any example usage of the pattern + function combo so I've added one.






[CLJ-1475] :post condition causes compiler error with recur Created: 25/Jul/14  Updated: 29/Jul/14

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

Type: Defect Priority: Minor
Reporter: Steve Miner Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler

Attachments: File clj-1475.diff    
Patch: Code and Test
Approval: Triaged

 Description   

Michael O'Keefe <michael.p.okeefe@gmail.com> posted on the mailing list an example of code that causes a compiler error only if a :post condition is added. Here's my slightly modified version:

(defn g
  [xs acc]
  {:pre [(or (nil? xs) (sequential? xs))]
   :post [(number? %)]}
  (if (seq xs)
     (recur (next xs) (+ (first xs) acc))
     acc))

CompilerException java.lang.UnsupportedOperationException: Can only recur from tail position

The work-around is to wrap the body in a loop that simply rebinds the original args.



 Comments   
Comment by Steve Miner [ 25/Jul/14 9:53 AM ]

A macro expansion shows that body is placed in a let form to capture the result for later testing with the post condition, but the recur no longer has a proper target. The work-around of using a loop form is easy once you understand what's happening but it's a surprising limitation.

Comment by Steve Miner [ 25/Jul/14 9:55 AM ]

Use a local fn* around the body and call it with the original args so that the recur has a proper target. Update: not good enough for handling destructuring. Patch withdrawn.

Comment by Michael Patrick O'Keefe [ 25/Jul/14 10:37 AM ]

Link to the original topic discussion: https://groups.google.com/d/topic/clojure/Wb1Nub6wVUw/discussion

Comment by Steve Miner [ 25/Jul/14 1:42 PM ]

Patch withdrawn because it breaks on destructured args.

Comment by Steve Miner [ 25/Jul/14 5:27 PM ]

While working on a patch, I came up against a related issue: Should the :pre conditions apply to every recur "call". Originally, I thought the :pre conditions should be checked just once on the initial function call and never during a recur. People on the mailing list pointed out that the recur is semantically like calling the function again so the :pre checks are part of the contract. But no one seemed to want the :post check on every recursion, so the :post would happen only at the end.

That means automatically wrapping a loop (or nested fn* call) around the body is not going to work for the :pre conditions. A fix would have to bring the :pre conditions inside the loop.

Comment by Steve Miner [ 26/Jul/14 8:54 AM ]

I'm giving up on this bug. My approach was adding too much complexity to handle an edge case. I recommend the "loop" work-around to anyone who runs into this problem.

(defn g2
  [xs acc]
  {:pre [(or (nil? xs) (sequential? xs))]
   :post [(number? %)]}
  (loop [xs xs acc acc]
    (if (seq xs)
       (recur (next xs) (+ (first xs) acc))
       acc)))
Comment by Ambrose Bonnaire-Sergeant [ 26/Jul/14 10:29 AM ]

Add patch that handles rest arguments and destructuring.

Comment by Michael Patrick O'Keefe [ 26/Jul/14 10:57 AM ]

With regard to Steve's question on interpreting :pre, to me I would expect g to act like the case g3 below which uses explicit recursion (which does work and does appear to check the :pre conditions each time and :post condition once):

(defn g3
  [xs acc]
  {:pre [(or (sequential? xs) (nil? xs)) (number? acc)]
   :post [(number? %)]}
  (if (seq xs)
    (g3 (next xs) (+ (first xs) acc))
    acc))
Comment by Ambrose Bonnaire-Sergeant [ 26/Jul/14 11:42 AM ]

Patch clj-1475.diff handles destructuring, preconditions and rest arguments

Comment by Steve Miner [ 26/Jul/14 4:04 PM ]

The clj-1475.diff patch looks good to me.

Comment by Alex Miller [ 27/Jul/14 7:18 AM ]

Please don't use "patch" as a label - that is the purpose of the Patch field. There is a list of good and bad labels at http://dev.clojure.org/display/community/Creating+Tickets

Comment by Steve Miner [ 27/Jul/14 11:32 AM ]

More knowledgeable commenters might take a look at CLJ-701 just in case that's applicable to the proposed patch.

Comment by Kevin Downey [ 29/Jul/14 1:35 AM ]

re clj-701

it is tricky to express loop expression semantics in jvm byte code, so the compiler sort of punts, hoisting expression loops in to anonymous functions that are immediately invoked, closing over whatever is in scope that is required by the loop, this has some problems like those seen in CLJ-701, losing type data which the clojure compiler doesn't track across functions, the additional allocation of function objects (the jit may deal with that pretty well, I am not sure) etc.

where the world of clj-701 and this ticket collide is the patch on this ticket lifts the function body out as a loop expression, which without the patch in clj-701 will have the issues I listed above, but we already have those issues anywhere something that is difficult to express in bytecode as an expression (try and loop) is used as an expression, maybe it doesn't matter, or maybe clj-701 will get fixed in some way to alleviate those issues.

general musings

it seems like one feature people like from asserts is the ability to disable them in production (I have never actually seen someone do that with clojure), assert and :pre/:post have some ability to do that (it may only work at macroexpansion time, I don't recall) since the hoisting of the loop could impact performance it might be nice to have some mechanism to disable it (maybe using the same flag assert does?).





[CLJ-1473] Badly formed pre/post conditions silently passed Created: 24/Jul/14  Updated: 19/Jul/15

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

Type: Enhancement Priority: Major
Reporter: Brandon Bloom Assignee: Unassigned
Resolution: Unresolved Votes: 4
Labels: errormsgs, ft

Attachments: Text File 0001-Validate-that-pre-and-post-conditions-are-vectors.patch     Text File CLJ-1473_v02.patch     Text File CLJ-1473_v03.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Before:

user=> ((fn [x] {:pre (pos? x)} x) -5) ; ouch!
-5
user=> ((fn [x] {:pre [(pos? x)]} x) -5) ; meant this
AssertionError Assert failed: (pos? x)  user/eval4075/fn--4076 (form-init5464179453862723045.clj:1)

After:

user=> ((fn [x] {:pre (pos? x)} x) -5)
CompilerException java.lang.IllegalArgumentException: Pre and post conditions should be vectors, compiling:(NO_SOURCE_PATH:1:2) 
user=> ((fn [x] {:pre [(pos? x)]} x) -5)                                  
AssertionError Assert failed: (pos? x)  user/eval2/fn--3 (NO_SOURCE_FILE:2)
user=> ((fn [x] {:post (pos? x)} x) -5)
CompilerException java.lang.IllegalArgumentException: Pre and post conditions should be vectors, compiling:(NO_SOURCE_PATH:3:2) 
user=> ((fn [x] {:post [(pos? x)]} x) -5)              
AssertionError Assert failed: (pos? x)  user/eval7/fn--8 (NO_SOURCE_FILE:4)

Patch: CLJ-1473_v03.patch
Screened by: Alex Miller



 Comments   
Comment by Alex Miller [ 29/Apr/15 1:54 PM ]

Would be nice to include the bad condition in the error (maybe via ex-info?) and also have tests.

Comment by Brandon Bloom [ 03/May/15 12:11 PM ]

New patch includes tests. Unfortunately, can't call ex-info directly due to bootstrapping concerns. Instead, just calls ExceptionInfo constructor directly.

Comment by Alex Miller [ 04/May/15 9:41 AM ]

Bug in the reporting: {:post pre} should be {:post post}.

Test should be improved as it could have caught that.

Comment by Brandon Bloom [ 04/May/15 7:25 PM ]

Good catch with the pre/post copy/paste screw up. Didn't enhance the test though, since that would involve creating an ex-info friendly variant of fails-with-cause





[CLJ-1472] The locking macro fails bytecode verification on ART runtime Created: 23/Jul/14  Updated: 30/Jul/15

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

Type: Defect Priority: Minor
Reporter: Adam Clements Assignee: Unassigned
Resolution: Unresolved Votes: 4
Labels: None
Environment:

Android ART runtime


Attachments: Text File 0001-CLJ-1472-Locking-macro-without-explicit-monitor-ente.patch    
Patch: Code
Approval: Triaged

 Description   

Android ART runs compile time verification on bytecode and was failing on any usage of the locking macro. Examination of the bytecode as compared to a java synchronized block shows up a number of differences:
https://gist.github.com/AdamClements/2ae6c4919964b71eb470

Having the monitor-enter inside the try block seems wrong to me, as surely if the lock fails to be acquired, it shouldn't be released with monitor-exit. Moving the monitor enter outside the try block seems to have resolved the issue and android no longer complains about usages of locking and all clojure tests still pass.

Java's generated code goes further and catches any exceptions generated by the monitor-exit itself and retries indefinitely (I believe the logic is that then at least your deadlock is in the right place, and not next time something else attempts to acquire a lock on the same object). I don't think that this can be replicated in clojure without getting down to the bytecode emitting level though and it doesn't seem to be an issue for the ART verifier.



 Comments   
Comment by Adam Clements [ 24/Jul/14 11:17 AM ]

After using this a little more, I've found that moving this outside the try block breaks nREPL.

Looking at the bytecode, the monitorenter for the locking in clojure.tools.nrepl.middleware.session/session-out and in a few other places ends up in an entirely different method definition and we now get a JVM IllegalMonitorStateException as well as an ART verification error for this function.

Comment by Andy Fingerhut [ 01/Aug/14 9:08 PM ]

Adam, I cannot comment on whether your patch is of interest or not, but it is true that no patch will be committed to Clojure if the author has not signed a Contributor Agreement, which can now be done on-line at http://clojure.org/contributing

Comment by Adam Clements [ 04/Aug/14 4:24 PM ]

Uploaded a new patch (and signed the contributor agreement). This passes both the JVM and ART bytecode verification, The extra try/catch around the monitor exit is optional (verification passes with or without it) but where the java version retries monitor-exit indefinitely and shows the deadlock at the right time, without catching errors in the monitor-exit an undetermined monitor-enter in the future might fail, not showing up the actual bug.

It's not very pretty, but without finer grained control of the generated bytecode, this is the best I could do.

Comment by Adam Clements [ 25/Nov/14 8:31 AM ]

Have just tested with Lollipop, and this patch might no longer be sufficient.

Getting in touch with the ART guys to see if they can shed a little more light and verify whether it will work on the current master branch of AOSP

Comment by Adam Clements [ 25/Nov/14 9:49 AM ]

Bug filed with AOSP project, hopefully they can shed some light on whether it is our problem and if so how we can fix it.

https://code.google.com/p/android/issues/detail?id=80823

Comment by Adam Clements [ 28/Nov/14 11:03 AM ]

I have uploaded an alternative implementation of the locking macro (0001-CLJ-1472-Locking-macro-without-explicit-monitor-ente.patch) which cheats a little - the synchronized block is actually implemented in Java and so guarantees compatibility. This is at the cost of a little extra indirection and the naming/location could probably be better.

But it does fix the bug and work on all versions of android, android + art and the jvm. Would this approach be acceptable?

Comment by Kevin Downey [ 08/Dec/14 1:12 PM ]

I have yet to see any evidence that the bytecode clojure is generating in some way violates the jvm spec, so I suspect the issue is clojure requires a jvm to run, and android doesn't provide a jvm, just something that looks like one if you don't tread outside the beaten path.

Comment by Kevin Downey [ 08/Dec/14 1:27 PM ]

given the structured locking verbiage in https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-2.html#jvms-2.11.10, `(locking nil)` may generate bytecode whose runtime behavior violates structured locking. the first patch on this issue can cause the compiler to emit monitorenter/exit instructions in different methods, which definitely violates structured locking

Comment by Adam Clements [ 09/Dec/14 10:45 AM ]

Yes, the first patch was definitely wrong, I left it for some context to the conversation, but it's probably best to just remove it for clarity.

For anyone following this conversation who doesn't want to decompile and observe the bytecode, here's a gist with the difference between a java synchronized block and clojure locking https://gist.github.com/AdamClements/2ae6c4919964b71eb470

I'm finding it hard to work out where the deviation from the spec occurs too, though I can see the difference with the Java version, if anything, the Clojure version looks closer to what's described in the spec than the Java one!

If someone with more knowledge than me on the subject could engage on the AOSP bug https://code.google.com/p/android/issues/detail?id=80823 then perhaps we could settle this as an android bug which is too focussed on the java implementation rather than the JVM spec, or perhaps they'll find something that's wrong with the Clojure implementation. I have uploaded the original clojure behaviour and asked them for some more explanation on why it is failing.

Comment by Adam Clements [ 09/Dec/14 11:09 AM ]

The response from the ART guys about what they think we're violating is:

The section on "Structured locking" contains the following:

"[...] implementations [...] are permitted but not required to enforce
both of the following two rules guaranteeing structured locking. [...]"

ART currently enforces both rules at verification time, including

"At no point during a method invocation may the number of monitor exits
performed by T on M since the method invocation exceed the number of
monitor entries performed by T on M since the method invocation."

Comment by Adam Clements [ 09/Dec/14 11:32 AM ]

If for example instruction https://gist.github.com/AdamClements/2ae6c4919964b71eb470#file-test_locks-class-L24 or the monitor-enter itself on the next line were to fail, couldn't it could end up in the finally clause and attempt to release the lock even though it has never been captured?

I think this violates the structured locking rules in the jvm spec you linked to.

Comment by Kevin Downey [ 09/Dec/14 1:15 PM ]

an interesting question about structured locking, is does the specification refer to the static bytecode or the runtime behavior of the bytecode. given the bytecode linked(https://gist.github.com/AdamClements/2ae6c4919964b71eb470#file-test_locks-class-L24), the static bytecode has the same number of entries and exits, but the dynamic behavior may be different. I wonder which one the art guys claim to be enforcing at verification time (it seems like it would have to be the static bytecode, not the dynamic properties, but then they shouldn't be failing to verify this). looking at the google code issue, the comment https://code.google.com/p/android/issues/detail?id=80823#c6 was made by the same dev as https://code.google.com/p/android/issues/detail?id=80823#c3, so I sort of suspect there is some miscommunication going on. It is not clear in what context the dev is replying in, since in the previous comment you mention splitting monitor-enter and exit across methods. I think things would be much clearer if all patches, specialized clojure android builds, etc, were gotten rid of, then with a vanilla clojure jar you get a javap dump of what fails to verify, then just take that over to the android issue tracker and ask "hey, this fails to verify, why?"

Comment by Adam Clements [ 11/Dec/14 9:15 AM ]

Yeah, I shouldn't have confused it with the patched versions. The gist and the currently uploaded version use the vanilla clojure version of the locking macro now though.

I think the issue comes from the exception table and the instructions that covers. If line 24 can throw for example, you would end up at runtime with a monitor-exit, having never encountered a monitor-enter.





[CLJ-1458] Use transients in merge and merge-with Created: 04/Jul/14  Updated: 22/Jun/15

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

Type: Enhancement Priority: Critical
Reporter: Yongqian Li Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: performance

Attachments: Text File 0001-very-simple-test-of-the-merge-function.patch     Text File clj-1458-4.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.

Patches:

  • clj-1458-4.patch (code)
  • merge-test-2.patch (tests)

Move merge and merge-with later to leverage transduce. Leave older version as merge1 for use in cases prior to new merge and merge-with definition.

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.





[CLJ-1456] The compiler ignores too few or too many arguments to throw Created: 30/Jun/14  Updated: 04/May/15

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

Type: Enhancement Priority: Major
Reporter: Alf Kristian Støyle Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler, ft

Attachments: Text File clj-1456-4.patch     Text File v3_0001-CLJ-1456-counting-forms-to-catch-malformed-throw-for.patch    
Patch: Code and Test
Approval: Triaged

 Description   

The compiler does not fail on "malformed" throw forms:

user=> (defn foo [] (throw))
#'user/foo

user=> (foo)
NullPointerException   user/foo (NO_SOURCE_FILE:1)

user=> (defn bar [] (throw Exception baz))
#'user/bar

user=> (bar)
ClassCastException java.lang.Class cannot be cast to java.lang.Throwable  user/bar (NO_SOURCE_FILE:1)

; This one works, but ignored-symbol, should probably not be ignored
user=> (defn quux [] (throw (Exception. "Works!") ignored-symbol))
#'user/quux

user=> (quux)
Exception Works!  user/quux (NO_SOURCE_FILE:1)

The compiler can easily avoid these by counting forms.

Patch: clj-1456-4.patch

Screened by: Alex Miller



 Comments   
Comment by Alf Kristian Støyle [ 30/Jun/14 11:56 AM ]

Not sure how to create a test for the attached patch. Will happily do so if anyone has a suggestion.

Comment by Alex Miller [ 30/Jun/14 12:23 PM ]

Re testing, I think the examples you give are good - you should add tests to test/clojure/test_clojure/compilation.clj that eval the form and expect compilation errors. I'm sure you can find similar examples.

Comment by Alf Kristian Støyle [ 30/Jun/14 2:01 PM ]

Newest patch also contains a few tests.

Comment by Andy Fingerhut [ 29/Aug/14 4:54 PM ]

All patches dated Jun 30 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 this patch. See section "Updating Stale Patches" on this wiki page for some tips on updating patches: http://dev.clojure.org/display/community/Developing+Patches

Alf, it can help avoid confusion if different patches have different file names. JIRA lets you create multiple attachments with the same name, but I wouldn't recommend it.

Comment by Alf Kristian Støyle [ 30/Aug/14 2:18 AM ]

It was easy to fix the patch. Uploaded the new patch v3_0001-CLJ-1456-counting-forms-to-catch-malformed-throw-for.patch, which applies cleanly to the current master.

Comment by Andy Fingerhut [ 08/Jan/15 6:07 PM ]

Alf, 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 Alf Kristian Støyle [ 10/Jan/15 9:12 AM ]

Removed both obsolete attachments. So shouldn't be confusing any more

Comment by Alex Miller [ 04/May/15 9:31 AM ]

-4 patch is same, just refreshed to apply to master





[CLJ-1454] Add a swap! that returns old value Created: 28/Jun/14  Updated: 02/Mar/15

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

Type: Enhancement Priority: Major
Reporter: Philip Potter Assignee: Unassigned
Resolution: Unresolved Votes: 7
Labels: atom

Approval: Triaged

 Description   

Sometimes, when mutating an atom, it's desirable to know what the value before the swap happened. The existing swap! function returns the new value, so is unsuitable for this use case. Currently, the only option is to roll your own using a loop and compare-and-set!

An example of this would be where the atom contains a PersistentQueue and you want to atomically remove the head of the queue and process it: if you run (swap! a pop), you have lost the reference to the old head of the list so you can't process it.

It would be good to have a new function swap-returning-old! which returned the old value instead of the new.



 Comments   
Comment by Philip Potter [ 28/Jun/14 4:00 PM ]

Overtone already defines functions like this in overtone.helpers.ref, which get used by overtone.libs.event. These return both the old and the new value, although in all existing use cases only the old value gets used.

flatland/useful defines a trade! fn which returns the old value, although the implementation is less clean than a compare-and-set! based solution would be.

Comment by Philip Potter [ 29/Jun/14 6:23 AM ]

Chris Ford suggested "swap-out!" as a name for this function. I definitely think "swap-returning-old!" isn't the ideal name.

Comment by Jozef Wagner [ 30/Jun/14 1:33 AM ]

I propose a switch! name. The verb switch is defined as "substitute (two items) for each other; exchange.", and as you get the old value back, it evokes slightly the exchange of items.

Comment by Philip Potter [ 30/Jun/14 3:03 AM ]

Medley also has a deref-swap! which does the same thing.

Comment by Alex Miller [ 30/Jun/14 8:20 AM ]

I think deref-swap! seems like a morally equivalent name to Java's AtomicReference.getAndSet() which is the same idea.

Comment by Philip Potter [ 30/Jun/14 1:19 PM ]

Funny you say that Alex, because prismatic/plumbing defines a get-and-set! (also defined by other projects), equivalent to deref-reset! in medley. Plumbing also defines swap-pair! which returns both old and new values, like the overtone fn, although once again the only usage I can find only uses the old value.

Comment by Alex Miller [ 30/Jun/14 3:37 PM ]

I think it's important to retain the notion that you are not switching/exchanging values but applying the update model of applying a function to the old value to produce the new value. I don't even particularly like "swap!" as I think that aspect is lost in the name (alter and alter-var-root are better). I like that "deref-swap!" combines two words with existing connotations and orders them appropriately.

Comment by Timothy Baldridge [ 30/Jun/14 3:43 PM ]

except that that naming doesn't fit well compared to functions like nfirst which are defined as (comp next first). This function is not (comp deref swap!).





[CLJ-1452] clojure.core/*rand* for seedable randomness Created: 20/Jun/14  Updated: 19/Jul/15

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

Type: Enhancement Priority: Major
Reporter: Gary Fredericks Assignee: Unassigned
Resolution: Unresolved Votes: 6
Labels: math

Attachments: Text File CLJ-1452.patch    
Patch: Code and Test
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





[CLJ-1451] Add take-until Created: 20/Jun/14  Updated: 09/Jan/15

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

Type: Enhancement Priority: Major
Reporter: Alexander Taggart Assignee: Unassigned
Resolution: Unresolved Votes: 4
Labels: None

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-take-until.patch    
Patch: Code and Test
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)

Impl:

(defn take-until
  "Returns a lazy sequence of successive items from coll until
  (pred item) returns true, including that item. pred must be
  free of side-effects."
  [pred coll]
  (lazy-seq
    (when-let [s (seq coll)]
      (if (pred (first s))
        (cons (first s) nil)
        (cons (first s) (take-until pred (rest s)))))))

List of other suggested names: take-upto, take-to, take-through. It is not easy to find something in English that is short and unambiguously means "up to and including". That is one of the dictionary definitions for "through".



 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





[CLJ-1446] (def v) with no init supplied destroys #'v metadata Created: 13/Jun/14  Updated: 31/Jul/15

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

Type: Enhancement Priority: Minor
Reporter: Nahuel Greco Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None

Approval: Triaged

 Description   

(def a) destroys #'a metadata, check this:

(def ^:mykey a 1)

(meta #'a)              ;; ok, :mykey is present

(let [v (def a)]
   [(meta v)            ;; NO :mykey present, metadata destroyed
    (identical? v #'a)  ;; true, we are talking of the same var
   ])

(meta #'a)              ;; NO :mykey present

If this is not a bug but a "feature", then we have at least two problems:

1- The def special form documentation doesn't state this behaviour at all, it needs to be clarified. With the current documentation it seems as doing a def with no init supplied will not make any side-effect at all, and this is not true for the var metadata.

2- defmulti uses this form to lookup the var and check if it already binds to a MultiFn, if that is the case then defmulti does nothing... but it really does something, defmulti will destroy the original var metadata in the (supposedly non-destructive) check. This is the involved defmulti fragment:

(let [v# (def ~mm-name)]
  (when-not (and (.hasRoot v#) (instance? clojure.lang.MultiFn (deref v#)))
   ...


 Comments   
Comment by Alex Miller [ 13/Jun/14 4:14 PM ]

I think this is mostly a dupe of CLJ-1148 but I'll leave it as it states the specific problem more precisely.

Comment by Nahuel Greco [ 13/Jun/14 7:35 PM ]

Alex Miller: It seems CLJ-1148 is an special case where this problem shows, but the patches in CLJ-1148 only fixes the issues for defonce, not generally for def, not for defmulti and not clarifies this behaviour in the def special form documentation.

Comment by Stuart Halloway [ 31/Jul/15 2:49 PM ]

I am pretty sure we have been here before, and decided that def is working as desired. (If anybody can find the thread/ticket please add a link.) I think this should be a doc enhancement.

If the behavior of defmethod is a separate bug, please make a separate ticket for that, showing an example problem.

Comment by Andy Fingerhut [ 31/Jul/15 3:00 PM ]

CLJ-1213 might be related, but it doesn't mention metadata, only (def foo) without init value given.





[CLJ-1416] Support transients in gvec Created: 06/May/14  Updated: 02/Oct/14

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

Type: Enhancement Priority: Minor
Reporter: Michał Marczyk Assignee: Michał Marczyk
Resolution: Unresolved Votes: 1
Labels: collections, transient

Attachments: Text File 0001-CLJ-1416-transients-hash-caching-for-gvec-Object-met.patch     Text File 0002-CLJ-1416-transients-hash-caching-interop-improvement.patch     Text File 0003-CLJ-1416-transients-hash-caching-interop-improvement.patch     Text File 0004-CLJ-1416-transients-hash-caching-interop-improvement.patch    
Patch: Code
Approval: Triaged

 Description   

Vectors of primitives produced by vector-of do not support transients.

core.rrb-vector implements transient support for vectors of primitives. Such transient-enabled vectors of primitives can be obtained in a number of ways: (1) using a gvec instance as an argument to fv/catvec (if RRB concatenation happens, which is not guaranteed) or fv/subvec; (2) passing a gvec instance to fv/vec, which as of core.rrb-vector 0.0.11 will simply rewrap the gvec tree in an RRB wrapper; (3) using fv/vector-of instead of clojure.core/vector-of. Native support in gvec would still be useful as part of an effort to make supported functionality consistent across vector flavours (see CLJ-787 in this connection); gvec is also simpler and still has (and is likely to maintain) a performance edge.

A port of core.rrb-vector's transient support to gvec is available here:

https://github.com/michalmarczyk/clojure/tree/transient-gvec

I'll bring it up to date with current master shortly.

See the clojure-dev thread for some benchmarks:

https://groups.google.com/d/msg/clojure-dev/9ozYI1e5SCM/BAIazVOkUmcJ



 Comments   
Comment by Michał Marczyk [ 13/May/14 5:32 AM ]

Here's the current version of the patch (0001-CLJ-1416-transients-hash-caching-for-gvec-Object-met.patch). It includes a few additional changes – here's the commit message:

CLJ-1416: transients, hash caching for gvec, Object methods for gvec seqs

  • Adds transient support to gvec
  • Adds hash{eq,Code} caching to gvec and gvec seqs
  • Implements hashCode, equals, toString for gvec seqs

https://github.com/michalmarczyk/clojure/tree/transient-gvec-1.6

Comment by Michał Marczyk [ 05/Jul/14 2:59 AM ]

Here's an updated patch with some additional interop-related improvements.

The new commit message:

CLJ-1416: transients, hash caching, interop improvements for gvec

  • Adds transient support to gvec
  • Adds hash{eq,Code} caching to gvec and gvec seqs
  • Implements hashCode, equals, toString for gvec seqs
  • Correctly implements iterator-related methods for gvec and gvec seqs
  • Introduces throw-unsupported and caching-hash (both marked private)
Comment by Andy Fingerhut [ 29/Aug/14 4:48 PM ]

Patch 0002-CLJ-1416-transients-hash-caching-interop-improvement.patch dated Jul 5 2014 no longer applied cleanly to latest master after some commits were made to Clojure on Aug 29, 2014. It did apply cleanly before that day.

I have not checked how easy or difficult it might be to update this patch. See section "Updating Stale Patches" on this wiki page for some tips on updating patches: http://dev.clojure.org/display/community/Developing+Patches

Comment by Michał Marczyk [ 29/Aug/14 5:07 PM ]

Patch updated to apply cleanly to master.

Comment by Brandon Bloom [ 02/Oct/14 12:28 PM ]

Maybe this should be another ticket, but it would affect this patch, so I'll mention it here:

The ArrayManager interface is an incomplete abstraction. The original gvec code plus the new transients codepaths rely on System/arraycopy, rather than .arraycopy on the manager object. This means that it's impossible to create gvecs backed by non-JVM arrays. Or, in my case, to create a gvec of nibbles backed by an array of longs. See https://gist.github.com/brandonbloom/441a4b5712729dec7467

Comment by Brandon Bloom [ 02/Oct/14 1:34 PM ]

The current patch has a bug on line 762:

(let [node ^clojure.core.VecNode (.ensureEditable this node)

There is no such signature, only these:

(ensureEditable [this]
(ensureEditable [this node shift]

I discovered this problem using https://github.com/ztellman/collection-check

Comment by Michał Marczyk [ 02/Oct/14 2:46 PM ]

Thanks for the catch! Fixed patch attached. (There was in fact one more bug in editableArrayFor, also fixed in this version.)

Comment by Michał Marczyk [ 02/Oct/14 2:57 PM ]

As for gvecs of nibbles, could that be a separate ticket with patches building on top of this one?

On a separate note, core.rrb-vector could support vectors of nibbles as an extra feature (and adopt built-in gvec's representation if indeed the built-in gvec comes to support this feature at some point). Do you think that'd be useful?

Comment by Michał Marczyk [ 02/Oct/14 3:01 PM ]

Of course vectors of nibbles could be implemented today with a separate vector type wrapping a gvec of longs, but the implementation would be more involved. I wonder what kind of performance difference there would be between the wrapper approach and the "nibble AM" approach…





[CLJ-1414] sort's docstring should say whether it is stable Created: 02/May/14  Updated: 28/Dec/14

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

Type: Enhancement Priority: Major
Reporter: Phill Wolf Assignee: Unassigned
Resolution: Unresolved Votes: 2
Labels: collections, docstring, ft

Attachments: Text File clj-1414-v1.patch    
Patch: Code
Approval: Triaged

 Description   

sort's docstring does not address whether the sort will be stable.

Stability is a useful property. It appears to be customary among programming tools to document whether their sort is stable. Java's Collections javadoc pledges a stable sort. The man-page of GNU coreutils sort in Ubuntu mentions its stability. The perldoc of Perl's sort function indicates it is a stable sort now but was not always.

Pillars of the Clojure community have commented on sort's stability:

(1) A recent book assembled by Cognitect consultants, "Clojure Cookbook", says Clojure's sort function "uses Java's built-in sort" and that "[t]he sort is also stable".

(2) In a 2011 discussion thread, "Clojure sort: is it specified to be stable for all targets?" https://groups.google.com/forum/#!topic/clojure/j3aNAmEJW9A , Stuart Sierra replied that "if it's not specified in the doc string, then it's not a promise. That said, [...] I would generally expect a language built-in `sort` routine to be stable, so take that for what it's worth."

Screened by: Alex Miller



 Comments   
Comment by Alex Miller [ 05/May/14 10:23 AM ]

Sounds reasonable. Needs patch from contributor.

Comment by Andy Fingerhut [ 30/Aug/14 3:07 PM ]

Patch clj-1414-v1.patch dated Aug 30 2014 adds the sentence "Guaranteed to be stable: equal elements will not be reordered." to the doc strings of both sort and sort-by.





[CLJ-1403] ns-resolve might throw ClassNotFoundException but should return nil Created: 14/Apr/14  Updated: 31/Jul/15

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

Type: Defect Priority: Major
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: None

Attachments: Text File 0001-CLJ-1403-ns-resolve-returns-nil-if-class-is-not-foun.patch    
Patch: Code and Test
Approval: Triaged

 Description   

The doc of ns-resolve states that in case the symbol cannot be resolved, it should return nil.

user=> (doc ns-resolve)
-------------------------
clojure.core/ns-resolve
([ns sym] [ns env sym])
  Returns the var or Class to which a symbol will be resolved in the
  namespace (unless found in the environment), else nil.  Note that
  if the symbol is fully qualified, the var/Class to which it resolves
  need not be present in the namespace.
nil

However if the symbol contains dots and is not a resolvable Class, a ClassNotFoundException is thrown

user=> (ns-resolve *ns* 'foo.bar)
ClassNotFoundException foo.bar  java.net.URLClassLoader$1.run (URLClassLoader.java:372)
user=> (pst *e)
ClassNotFoundException foo.bar
	java.net.URLClassLoader$1.run (URLClassLoader.java:372)
	java.net.URLClassLoader$1.run (URLClassLoader.java:361)
	java.security.AccessController.doPrivileged (AccessController.java:-2)
	java.net.URLClassLoader.findClass (URLClassLoader.java:360)
	clojure.lang.DynamicClassLoader.findClass (DynamicClassLoader.java:61)
	java.lang.ClassLoader.loadClass (ClassLoader.java:424)
	java.lang.ClassLoader.loadClass (ClassLoader.java:357)
	java.lang.Class.forName0 (Class.java:-2)
	java.lang.Class.forName (Class.java:340)
	clojure.lang.RT.classForName (RT.java:2065)
	clojure.lang.Compiler.maybeResolveIn (Compiler.java:6963)
	clojure.core/ns-resolve (core.clj:4026)
nil

The attached patch makes ns-resolve return nil in that case instead of throwing an exception



 Comments   
Comment by Alex Miller [ 14/Apr/14 2:07 PM ]

Can you include the (pst *e) ?

Comment by Nicola Mometto [ 14/Apr/14 2:10 PM ]

Added result of (pst *e) in the description

Comment by Andy Fingerhut [ 02/Oct/14 11:36 AM ]

Nicola, the patch 0001-CLJ-1403-ns-resolve-returns-nil-if-class-is-not-foun.patch dated 31 Aug 2014 applies cleanly to latest Clojure master as of Oct 1 2014, but fails to compile with JDK8. I haven't checked whether it compiles cleanly with other JDK versions yet.

Comment by Nicola Mometto [ 02/Oct/14 11:48 AM ]

Updated the patch so that it compiles fine on JDK8





[CLJ-1401] CompilerException / IllegalStateException when overriding vars Created: 10/Apr/14  Updated: 31/Jul/15

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

Type: Enhancement Priority: Minor
Reporter: Mike Anderson Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler, errormsgs

Approval: Triaged

 Description   
=> (ns foo)
nil
=> (def a 1)
#'foo/a
=> (ns bar (:require [foo :refer :all]))
nil
=> (def a 2)
CompilerException java.lang.IllegalStateException: a already refers to: #'foo/a in namespace: bar, compiling:(NO_SOURCE_PATH:4:1)
	clojure.lang.Compiler.analyzeSeq (Compiler.java:6745)
	clojure.lang.Compiler.analyze (Compiler.java:6529)
	clojure.lang.Compiler.analyze (Compiler.java:6490)
	clojure.lang.Compiler.eval (Compiler.java:6801)
	clojure.lang.Compiler.eval (Compiler.java:6760)
	clojure.core/eval (core.clj:3079)
	clojure.main/repl/read-eval-print--7095/fn--7098 (main.clj:240)
	clojure.main/repl/read-eval-print--7095 (main.clj:240)
	clojure.main/repl/fn--7104 (main.clj:258)
	clojure.main/repl (main.clj:258)
	clojure.main/repl-opt (main.clj:324)
	clojure.main/main (main.clj:422)
Caused by:
IllegalStateException a already refers to: #'foo/a in namespace: bar
	clojure.lang.Namespace.warnOrFailOnReplace (Namespace.java:88)
	clojure.lang.Namespace.intern (Namespace.java:72)
	clojure.lang.Compiler$DefExpr$Parser.parse (Compiler.java:534)
	clojure.lang.Compiler.analyzeSeq (Compiler.java:6738)
	clojure.lang.Compiler.analyze (Compiler.java:6529)

I would expect (at worst) a similar warning to the initial namespace loading, rather than an exception here.



 Comments   
Comment by Alex Miller [ 11/Apr/14 8:26 AM ]

Could you put together a better reproducible test case for this that does not depend on core.matrix? Also, please include the (pst *e) when it occurs.

Comment by Andy Fingerhut [ 11/Apr/14 10:19 AM ]

I have tried the smallest possible Leiningen project I could think of that would cause the warnings about redefinitions, to see if I could get the exception to occur. 'lein new try1' to create the skeleton project, then edit src/try1/core.clj to contain only the following function definitions:

(defn merge
  "This definition of merge replaces clojure.core/merge"
  [x y]
  (- x y))

(defn *
  [x y]
  (* x y))

Then start a REPL with 'lein repl', and I see this behavior:

user=> (require '[try1.core :as c])
WARNING: merge already refers to: #'clojure.core/merge in namespace: try1.core, being replaced by: #'try1.core/merge
WARNING: * already refers to: #'clojure.core/* in namespace: try1.core, being replaced by: #'try1.core/*
nil
user=> (require '[try1.core :as c] )
nil
user=> (require '[try1.core :as c] :reload)
WARNING: merge already refers to: #'clojure.core/merge in namespace: try1.core, being replaced by: #'try1.core/merge
WARNING: * already refers to: #'clojure.core/* in namespace: try1.core, being replaced by: #'try1.core/*
nil

Ths all looks like behavior as I would expect, and I did not see the exception that Mike reports.

It seems that either Ctrl+Alt+L in Counterclockwise does something different than (require ... :reload), or there is something different about Mike's namespace in addition to redefining names in clojure.core that is causing the problem.

Comment by Alex Miller [ 11/Apr/14 11:17 AM ]

Marking this as NR for now - would be happy to see it reopened with an easily reproducible test case.

Comment by Mike Anderson [ 12/Apr/14 12:41 AM ]

To reproduce:

(ns op)
(defn * [a b] (clojure.core/* a b)) ;; gives warning
(ns use-op (:require [op :refer :all])) ;; gives warning
(ns use-op (:require [op :refer :all])) ;; gives error!

I believe Counterclockwise is simply loading the namespace again with CTRL-Alt+L, which is causing the ns form to be re-executed.

The docstring implies that ns can be used multiple times ("Sets ns to the namespace named by name (unevaluated), creating it if needed") so I would certainly expect multiple invocations of ns to be a no-op

Comment by Alex Miller [ 03/Nov/14 10:24 AM ]

Duped in CLJ-1578.

Comment by Mike Anderson [ 09/Jun/15 3:54 AM ]

This is still affecting me, and causing breakage with the latest versions of core.matrix. I don't know if this is a regression or not, but it certainly happens in 1.7.0-RC1

Any chance we can get a fix for 1.7? It is really annoying to have code fail because of this and force of refactoring of user code (my use case is adding a new var to clojure.core.matrix namespace, compiler error in user code that previously defined a var with the same name).

Comment by Mike Anderson [ 09/Jun/15 3:59 AM ]

Closing because I think this is better handled in the related issue

Comment by Mike Anderson [ 09/Jun/15 5:05 AM ]

Reopening because CLJ-1578 apparently does not resolve this specific issue, it only covers vars in clojure.core.

I'd still like to see this fixed for all namespaces, not just clojure.core.

Comment by Mike Anderson [ 09/Jun/15 5:08 AM ]

Reproduction:

=> (ns foo)
nil
=> (def a 1)
#'foo/a
=> (ns bar (:require [foo :refer :all]))
nil
=> (def a 2)
CompilerException java.lang.IllegalStateException: a already refers to: #'foo/a in namespace: bar, compiling:(NO_SOURCE_PATH:1:1)
=> clojure-version
{:major 1, :minor 7, :incremental 0, :qualifier "RC1"}

Stack trace:

CompilerException java.lang.RuntimeException: Unable to resolve symbol: pst in this context, compiling:(NO_SOURCE_PATH:1:1)
clojure.lang.Compiler.analyze (Compiler.java:6543)
clojure.lang.Compiler.analyze (Compiler.java:6485)
clojure.lang.Compiler$InvokeExpr.parse (Compiler.java:3737)
clojure.lang.Compiler.analyzeSeq (Compiler.java:6735)
clojure.lang.Compiler.analyze (Compiler.java:6524)
clojure.lang.Compiler.analyze (Compiler.java:6485)
clojure.lang.Compiler$BodyExpr$Parser.parse (Compiler.java:5861)
clojure.lang.Compiler$FnMethod.parse (Compiler.java:5296)
clojure.lang.Compiler$FnExpr.parse (Compiler.java:3925)
clojure.lang.Compiler.analyzeSeq (Compiler.java:6731)
clojure.lang.Compiler.analyze (Compiler.java:6524)
clojure.lang.Compiler.eval (Compiler.java:6789)
Caused by:
RuntimeException Unable to resolve symbol: pst in this context
clojure.lang.Util.runtimeException (Util.java:221)
clojure.lang.Compiler.resolveIn (Compiler.java:7029)
clojure.lang.Compiler.resolve (Compiler.java:6973)
clojure.lang.Compiler.analyzeSymbol (Compiler.java:6934)
clojure.lang.Compiler.analyze (Compiler.java:6506)
clojure.lang.Compiler.analyze (Compiler.java:6485)

Comment by Nicola Mometto [ 09/Jun/15 5:16 AM ]

As I already commented in CLJ-1578, I don't think this is a bug and I think this ticket should be declined.

Overriding non clojure.core vars has always (since 1.2 at least) caused an exception to be thrown.

Comment by Nicola Mometto [ 09/Jun/15 5:23 AM ]

Mike, maybe it would make sense to bring this issue up in the clojure-dev ml to get some opinions?

Comment by Mike Anderson [ 09/Jun/15 5:42 AM ]

Re-classify it as a feature request, if you prefer.

I still regard it as a defect because I expect :refer :all to work sanely.

Either way, this issue keeps breaking user code in my area (data science / exploratory statistics / data management). The ability to use / refer all is very useful for setting up a convenient namespace for exploratory work, so I don't accept that forcing users to explicitly require every single var used (as Nicola suggests in CLJ-1578) is a practical workaround.

I've also had it cause problems when working at the REPL and reloading namespaces.

If the Clojure core team really wants to keep this annoying behaviour, can we at least have some way to turn it off at the library level? Perhaps some namespace metadata that I can add to the clojure.core.matrix namespace to stop this from triggering?

Comment by Nicola Mometto [ 09/Jun/15 6:23 AM ]

Mike, this is just my personal opinion, I'm not a part of the core team and I don't speak for them, this is why I suggested you wrote on the clojure-dev ml.

Also to clarify, this issue you're reporting cannot manifest itself while reloading namespaces as the exception is thrown as soon as the redefinition happens.

Comment by Alex Miller [ 09/Jun/15 8:47 AM ]

You could use :exclude for this

(ns bar (:require [foo :refer :all :exclude (a)]))
Comment by Mike Anderson [ 09/Jun/15 9:30 AM ]

Hi Alex, that works as a fix when the problem occurs, but doesn't solve the problem of future user code breakage, unless the user accurately anticipates what symbols might get added to "bar" in the future. Which again seems like an unreasonable burden on the user.

What I'm arguing for, I guess, is a default presumption that if the user defines a var in their own namespace, they are happy to replace a similarly named var in any namespaces that they have previously use'd / refer-all'd.

If the user is genuinely concerned about overriding things by accident, I'd be happy with a warn-on-replace which does something analogous to warn-on-reflection. I proposed something similar in CLJ-1257 a while back, even wrote a patch that solves the whole problem in this way. Can we get that patch or something similar in 1.7?

Comment by Nicola Mometto [ 09/Jun/15 10:22 AM ]

CLJ-1746 is relevant and I like that proposal much better than CLJ-1257

Comment by Mike Anderson [ 09/Jun/15 10:43 AM ]

Hi Nicola, CLJ-1746 looks like a reasonable suggestion but still doesn't address the problem here, for the same reason that :exclude doesn't (see my comment to Alex)

The fundamental issue is that the current behaviour causes user code to break when libraries are upgraded to add new vars and requires changes to user code to fix / work around it. I consider that broken behaviour, or at least very bad design.

This is especially since we are encouraged to choose good names: I quote from the library coding standards(http://dev.clojure.org/display/community/Library+Coding+Standards)

"Use good names, and don't be afraid to collide with names in other namespaces. That's what the flexible namespace support is there for."

It isn't very flexible when user code keep breaking.....

Comment by Nicola Mometto [ 09/Jun/15 10:53 AM ]

From the same page, just a two lines below:
"Be explicit and minimalist about dependencies on other packages. (Prefer :require :refer in 1.4+ or :use :only in 1.0-1.3)."

If users carelessly import a whole package, I'd say that's their fault. Since clojure >1.3 the popular consensus has been that :use/:refer :all are not a good idea and people have been moving away from that, preferring :require :refer or :require :as instead.

The few that still use :use/:refer :all do it mostly for backward compatibility or in tests (I myself do it in tools.reader for the former reason).

I really don't think this is such a bad design choice as you seem to think, and I think that most people in the community would agree that the current behaviour and drive towards using :require :refer/require :as in lieu of :use/:refer :all is way more beneficial than harmful

Comment by Mike Anderson [ 09/Jun/15 11:42 AM ]

Hi Nicola, I have no issue with people using explicit :refer / :require, and I agree it is normal practice. It's good to be explicit and I generally do that myself (except in test / demo code).

However we aren't talking about that case : this issue is most relevant in those situations where users (for their own legitimate reasons) have decided to import a whole namespace. This is often convenient (e.g. REPL usage), sometimes it is valuable for specific purposes (e.g. testing).

I personally care about this mostly from the perspective of a library author: I want users to be able to use the library in whatever way is most convenient (which may include importing all vars), and I don't want user code to break randomly when I make a new release. Note that this also means I don't have control over user code so any solution that involves explicit requires, excludes, or some other manual workarounds is not a practical solution.

You can say "that's their fault" but this is currently supposed to be supported in Clojure so I think it ought to work sanely.

Comment by Alex Miller [ 09/Jun/15 12:00 PM ]

I think the library / evolution argument is a good one and I like that it reduces breakage due to evolution of 3rd party libraries. (I feel very strongly about this in clojure.core itself which is auto-referred, less strongly otherwise.)

On the flip side, if we remove this error, we should be explicit about what we are giving up to fully consider it. Presumably we are at least giving up a helpful error that occurs in the case of an accidental override. Are there other impacts?

I do not expect that we're going to change anything in 1.7.

Comment by Stuart Halloway [ 31/Jul/15 3:10 PM ]

Recategorizing as a feature request, as the current behavior was the original intent.

Could a namespace-reflecting macro provide for this use case without requiring a change to core?





[CLJ-1398] Update URLs in javadoc.clj Created: 02/Apr/14  Updated: 17/May/15

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

Type: Enhancement Priority: Trivial
Reporter: Eli Lindsey Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: None

Attachments: Text File 0001-update-apache-commons-javadoc-location.patch     Text File 0002-add-javadoc-lookup-for-guava-and-apache-commons-lang.patch     Text File 0003-add-javadoc-lookup-for-jdk8.patch    
Patch: Code
Approval: Triaged

 Description   

Three minor fixes/enhancements to javadoc.clj:

0001 corrects the URLs for apache commons javadoc (the ones used in javadoc.clj no longer resolve).
0002 adds javadoc lookup for guava and apache commons lang3.
0003 adds javadoc lookup for jdk8.

(Note: contributor agreement is in the mail)



 Comments   
Comment by Andy Fingerhut [ 04/Apr/14 11:22 AM ]

Eli, thanks for the patches. It appears that you are not currently on the list of Clojure contributors here: http://clojure.org/contributing

It is the policy of the Clojure team only to incorporate patches submitted by people who have signed and submitted a Clojure CA. Were you interested in doing that?

Comment by Eli Lindsey [ 04/Apr/14 11:27 AM ]

> It is the policy of the Clojure team only to incorporate patches submitted by people who have signed and submitted a Clojure CA. Were you interested in doing that?

Yup! I mailed off the CA to Rich on Wednesday when this was filed; should be arriving shortly.

Comment by Eli Lindsey [ 09/May/14 8:18 PM ]

Just to note - Clojure CA went through and I'm listed on the contributors page now.





[CLJ-1386] Add transient? predicate Created: 17/Mar/14  Updated: 20/Apr/15

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

Type: Enhancement Priority: Major
Reporter: Devin Walters Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: collections, transient
Environment:

N/A


Attachments: Text File 0004-Add-transient-predicate.patch    
Patch: Code and Test
Approval: Triaged

 Description   

I've encountered situations where I wanted to check whether something was transient in order to know whether I should call assoc! or assoc, conj! or conj, etc.

This patch adds `transient?` as a predicate fn.



 Comments   
Comment by Alex Miller [ 17/Mar/14 10:21 AM ]

Patch needs a docstring and a test.

Comment by Devin Walters [ 17/Mar/14 4:42 PM ]

Alex: I figured that would be the case! Sorry about that. I've updated the patch. It now includes a docstring and has tests of `transient?` for #{}, [], and {}.

Thanks!

Comment by Alex Miller [ 17/Mar/14 9:48 PM ]

Thanks - please don't use the labels "patch" or "test" - those are covered by the Patch field.

Comment by Devin Walters [ 18/Mar/14 9:17 AM ]

Ah, sorry for the mixup Alex. I assumed you removed "patch" as a label the first time around to flag this ticket as still needing a vetted patch. My mistake.

Comment by Andy Fingerhut [ 21/Mar/14 1:42 PM ]

Patch 0001-Add-transient-predicate.patch dated Mar 17, 2014 applies cleanly to latest Clojure master, but fails a test because the new function transient? has no :added metadata. See most other Clojure functions in clojure.core for examples.

It also generates a new warning while running tests:

WARNING: transient? already refers to: #'clojure.core/transient? in namespace: clojure.test-clojure.data-structures, being replaced by: #'clojure.test-clojure.data-structures/transient?

There is an older (but equivalent) definition of transient? in test file data_structures.clj that should be removed when adding it to clojure.core

Comment by Devin Walters [ 22/Mar/14 11:29 PM ]

@Andy, the reason I did not add :added metadata is because I do not know if/when this patch will be accepted, and as a result, I don't really know if it will sneak into 1.6.X or 1.7. For now, I've put it in as 1.7. If it's in the running to be added sooner than that, let me know and I'll adjust it.

RE: The warning. Good catch. I've submitted a new patch which removes the private version of transient? from data_structures.clj. All tests pass.

Edit to Add: The latest patch as of this comment is now 0002-Add-transient-predicate.patch.

Comment by Andy Fingerhut [ 06/Aug/14 2:16 PM ]

Patch 0002-Add-transient-predicate.patch dated Mar 22 2014 no longer applies cleanly to latest Clojure master due to some changes committed earlier today. I haven't checked whether this patch is straightforward to update.

Comment by Devin Walters [ 06/Aug/14 4:11 PM ]

I've updated the patch to 0003-Add-transient-predicate.patch. This patch applies cleanly to the latest version of master.

Comment by Andy Fingerhut [ 29/Aug/14 4:44 PM ]

Patch 0003-Add-transient-predicate.patch dated Aug 6 2013 no longer applied cleanly to latest master after some commits were made to Clojure on Aug 29, 2014. It did apply cleanly before that day.

I have not checked how easy or difficult it might be to update this patch.

Comment by Devin Walters [ 31/Aug/14 12:01 AM ]

I've updated the patch to 0004-Add-transient-predicate.patch. This patch applies cleanly to the latest version of master.





[CLJ-1385] Docstrings for `conj!` and `assoc!` should suggest using the return value; effect not always in-place Created: 16/Mar/14  Updated: 06/May/15

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

Type: Enhancement Priority: Minor
Reporter: Pyry Jahkola Assignee: Unassigned
Resolution: Unresolved Votes: 2
Labels: collections, docstring, ft

Attachments: Text File CLJ-1385-reword-docstrings-on-transient-update-funct-2.patch     Text File CLJ-1385-reword-docstrings-on-transient-update-funct.patch    
Patch: Code
Approval: Triaged

 Description   

The docstrings of both `assoc!` and `conj!` say "Returns coll.", possibly suggesting the transient edit happens (always) in-place, `coll` being the first argument. However, this is not the case and the returned collection should always be the one that's used.

Approach: Replace "Returns coll." with "Returns an updated collection." in `conj!`, `assoc!`, `pop!` docstrings.

Patch: CLJ-1385-reword-docstrings-on-transient-update-funct-2.patch

Screened by: Alex Miller



 Comments   
Comment by Alex Miller [ 16/Mar/14 8:49 AM ]

When modifying transient collections, it is required to use the collection returned from functions like assoc!. The ! here indicates its destructive nature. The transients page (http://clojure.org/transients) describes the calling pattern pretty explicitly: "You must capture and use the return value in the next call."

I do not agree that we should be guiding programmers away from using functions like assoc! – transients are used as a performance optimization and using assoc! or conj! in a loop is often the fastest version of that. However I do think it would be helpful to make the docstring more explicit.

Comment by Gary Fredericks [ 05/Apr/14 10:23 AM ]

Alex I think you must have misread the ticket – the OP is suggesting guiding toward using the return value of assoc!, not avoiding assoc! altogether.

And the docstring is not simply inexplicit, it's actually incorrect specifically in the case that the OP pointed out. conj! and assoc do not return coll at the point where array-maps transition to hash-maps, and the fact that they do otherwise is supposed to be an implementation detail as far as I understand it.

Comment by Alex Miller [ 05/Apr/14 11:55 AM ]

@Gary - you're right, I did misread that.

assoc and conj both explicitly say "return a new collection" whereas assoc! and conj! say "Returns coll." I read that as "returns the modified collection" without regard to whether it's the identical instance, but I can read it your way too.

Would saying "Returns updated collection." transmit the right idea? Using "collection" instead of "coll" removes the concrete tie to the variable and "updated" hints more strongly that you should use the return value.

Comment by Pyry Jahkola [ 05/Apr/14 12:47 PM ]

@Alex, that update makes it sound right to me, FWIW.

Comment by Gary Fredericks [ 05/Apr/14 2:37 PM ]

Yeah, I think that's better. Thanks Alex. I'd be happy to submit a patch for that but I'm assuming patches are too heavy for this kind of change?

Comment by Andy Fingerhut [ 06/Apr/14 3:35 PM ]

Patches are exactly what has been done in the past for this kind of change, if it is in a doc string and not on the clojure.org web page.

Comment by Alex Miller [ 06/Apr/14 4:13 PM ]

Yup, patch desired.

Comment by Gary Fredericks [ 06/Apr/14 5:32 PM ]

Glad I asked.

Patch is attached that also updates the docstring for pop! which had the same issue, though arguably it's less important since afaik pop! does always return the identical collection (but I don't think this is part of the contract).

Comment by Andy Fingerhut [ 06/Aug/14 2:14 PM ]

Patch CLJ-1385-reword-docstrings-on-transient-update-funct.patch dated Apr 6 2014 no longer applies to latest Clojure master cleanly, due to some changes committed earlier today. I suspect it should be straightforward to update the patch to apply cleanly, given that they are doc string changes, but there may have been doc string changes committed to master, too.

Comment by Gary Fredericks [ 06/Aug/14 3:04 PM ]

Attached a new patch.





[CLJ-1381] Improve support for extending protocols to primitive arrays Created: 13/Mar/14  Updated: 30/Jul/15

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

Type: Enhancement Priority: Major
Reporter: Alex Miller Assignee: Unassigned
Resolution: Unresolved Votes: 4
Labels: protocols

Approval: Triaged

 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




[CLJ-1373] LazySeq should utilize cached hash from its underlying seq. Created: 09/Mar/14  Updated: 23/Jun/15

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

Type: Enhancement Priority: Minor
Reporter: Jozef Wagner Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: collections, performance
Environment:

1.6.0 master SNAPSHOT


Attachments: File clj-1373.diff    
Patch: Code
Approval: Triaged

 Description   

Even if underlying seq contains a cached hash, LazySeq computes it every time.

user=> *clojure-version*
{:major 1, :minor 7, :incremental 0, :qualifier "master", :interim true}
user=> (def a (range 100000))
#'user/a
user=> (time (hash a))
"Elapsed time: 21.812 msecs"
375952610
user=> (time (hash a))        ;; hash is cached
"Elapsed time: 0.036 msecs"
375952610
user=> (def b (seq a))
#'user/b
user=> (time (hash b))
"Elapsed time: 0.042 msecs"   ;; uses cached hash
375952610
user=> (def c (lazy-seq b))
#'user/c
user=> (time (hash c))        ;; SHOULD use underlying hash
"Elapsed time: 27.758 msecs"
375952610
user=> (time (hash c))        ;; SHOULD use underlying hash
"Elapsed time: 17.846 msecs"
375952610

Approach: If seq produced by LazySeq implementing IHashEq, use it to calculate the hasheq().
Patch: clj-1373.diff



 Comments   
Comment by Jozef Wagner [ 09/Mar/14 9:20 AM ]

Added patch which checks if underlying seq implements IHashEq and if yes, uses that hash instead of recomputing.

Comment by Alex Miller [ 04/May/15 9:34 AM ]

In this patch, can you update the else case (the original code) to use s rather than this, so seq() is not re-called?

Comment by Jozef Wagner [ 04/May/15 12:30 PM ]

Added patch [^clj-1373-2.diff] that reuses s for else case.

Comment by Alex Miller [ 23/Jun/15 2:15 PM ]

The -2 patch doesn't compile so I guess that was a bad suggestion.





[CLJ-1372] Inconsistent hash with java collections Created: 09/Mar/14  Updated: 16/Mar/15

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

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: Triaged

 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.





[CLJ-1360] clojure.string/split strips trailing delimiters Created: 18/Feb/14  Updated: 30/Jul/15

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

Type: Defect Priority: Minor
Reporter: Tim McCormack Assignee: Unassigned
Resolution: Unresolved Votes: 2
Labels: None

Approval: Triaged

 Description   

clojure.string/split and clojure.string/split-lines inherit the bizarre default behavior of java.lang.String#split(String,int) in stripping trailing consecutive delimiters:

(clojure.string/split "banana" #"an")
⇒ ["b" "" "a"]
(clojure.string/split "banana" #"na")
⇒ ["ba"]
(clojure.string/split "nanabanana" #"na")
⇒ ["" "" "ba"]

In the case of split-lines, processing a file line by line and rejoining results in truncation of trailing newlines in the file. In both cases, the behavior is surprising and cannot be inferred from the docstrings.

This behavior should either be fixed or documented.



 Comments   
Comment by Andy Fingerhut [ 18/Feb/14 10:51 AM ]

Probably documenting would be safer than changing the behavior at this point, given that some people may actually rely on the current behavior after testing, deploying, etc.

I don't currently have a suggestion for a modified doc string, but note that there are examples of this behavior and how one can use an extra "-1" limit argument at the end to get all split strings: http://clojuredocs.org/clojure_core/clojure.string/split

Comment by Crispin Wellington [ 21/May/15 10:46 PM ]

This bug just bit me. +1 to be fixed. If we just document and leave the behavior as is, then we have a surprising and inconsistent behaving split (why are inner empty values kept, but outer ones stripped?) that is different to every other split you've ever used. The optional -1 limit argument looks hacky but a fix could keep this -1 argument working.

EDIT: this looks to be java's string class behavior: http://stackoverflow.com/questions/2170557/split-method-of-string-class-does-not-include-trailing-empty-strings
Would be nice if limit defaulted to -1 on that type of clojure.string/split call.

Comment by Stuart Halloway [ 19/Jul/15 8:03 AM ]

This is really gross, and the original developer has been punched in the neck. (Ow.)

I hate the Java leakage, but given that this is already out there, and that people are likely already relying on both the default and the negative-arg behavior, I think the least bad bet is to document precisely the semantics we have.





[CLJ-1351] Clojure emits an unused "swapThunk" method for functions with keyword callsites Created: 14/Feb/14  Updated: 29/Apr/15

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

Type: Enhancement Priority: Major
Reporter: Nicola Mometto Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: compiler, ft, performance

Attachments: Text File 0001-remove-unused-swapThunk-method-generation.patch    
Patch: Code
Approval: Triaged

 Description   

This method is no longer used, I did a quick git blame and it look like it was used for an earlier implementation of keyword callsites and forgot to be removed in this commit https://github.com/clojure/clojure/commit/c7af275d4ee33cdc1794c8df8fa1e6d39039ac84

Removing this should reduce a bit the size of compile functions.

Screened by: Alex Miller






[CLJ-1329] Unused local variable in PersistentVector.cons() Created: 22/Jan/14  Updated: 29/Apr/15

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

Type: Enhancement Priority: Trivial
Reporter: Smit Shah Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: collections, ft

Attachments: Text File clj-1329-2.patch     Text File fix.patch    
Patch: Code
Approval: Triaged

 Description   

in src/jvm/clojure/lang/PersistentVector.java:168, there is an integer i being defined which is not being used anywhere in the method.

Patch: clj-1329-2.patch
Screened by: Alex Miller



 Comments   
Comment by Stuart Halloway [ 31/Jan/14 6:14 PM ]

Smit, can you please submit a CA? http://clojure.org/contributing

Comment by Smit Shah [ 02/Feb/14 1:16 PM ]

Stuart, I will send the CA via post ASAP.
It might take a couple of days to reach Rich though.

Comment by Smit Shah [ 01/Mar/14 11:51 AM ]

Stuart, I have successfully submitted the CA (http://clojure.org/contributing).
I guess now merging this patch shouldn't be a problem

Comment by Alex Miller [ 02/Mar/14 11:37 AM ]

Thanks Smit!

Comment by Andy Fingerhut [ 01/Oct/14 6:43 PM ]

Smit, instructions for creating a patch in the format expected by the screeners is given on the wiki page below. The one you have attached is not in the expected format.

http://dev.clojure.org/display/community/Developing+Patches

Comment by Alex Miller [ 29/Apr/15 2:28 PM ]

Added new patch - same diff but proper format





[CLJ-1305] Add optional not-found argument when invoking vectors or sets as functions Created: 12/Dec/13  Updated: 30/Dec/14

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

Type: Enhancement Priority: Minor
Reporter: Dave Tenny Assignee: Unassigned
Resolution: Unresolved Votes: 3
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    
Patch: Code and Test
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.





[CLJ-1298] Add more type predicate fns to core Created: 21/Nov/13  Updated: 03/May/15

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

Type: Enhancement Priority: Major
Reporter: Alex Fowler Assignee: Unassigned
Resolution: Unresolved Votes: 19
Labels: None

Approval: Triaged

 Description   

Add more built-in type predicates:

1) Definitely missing: (atom? x), (ref? x), (deref? x), (named? x), (map-entry? x), (lazy-seq? x).
2) Very good to have: (throwable? x), (exception? x), (pattern? x).

The first group is especially important for writing cleaner code with core Clojure.



 Comments   
Comment by Alex Miller [ 21/Nov/13 8:42 AM ]

In general many of the existing predicates map to interfaces. I'm guessing these would map to checks on the following types:

atom? = Atom (final class)
ref? = IRef (interface)
deref? = IDeref (interface)
named? = Named (interface, despite no I prefix)
map-entry? = IMapEntry (interface)
lazy-seq? = LazySeq (final class)

throwable? = Throwable
exception? = Exception, but this seems less useful as it feels like the right answer when you likely actually want throwable?
pattern? = java.util.regex.Pattern

Comment by Alex Fowler [ 21/Nov/13 9:02 AM ]

Yes, they do, and sometimes the code has many checks like (instance? clojure.lang.Atom x). Ok, you can write a little function (atom? x) but it has either to be written in all relevant namespaces or required/referred there from some extra namespace. All this is just a burden. For example, we have predicates like (var? x) or (future? x) which too map to Java classes, but having them abbreviated often makes possible to write a cleaner code.

I feel the first group to be especially significant for it being about core Clojure concepts like atom and ref. Having to fall to manual Java classes check to work with them feels inorganic. Of course we can, but why then do we have (var? x), (fn? x) and other? Imagine, for example:

(cond
(var? x) (...)
(fn? x) (...)
(instance? clojure.lang.Atom x) (...)
(or (instance? clojure.lang.Named x) (instance? clojure.lang.LazySeq x)) (...))

vs

(cond
(var? x) (...)
(fn? x) (...)
(atom? x) (...)
(or (named? x) (lazy-seq? x)) (...))

The second group is too, essential since these concepts are fundamental for the platform (but you're right with the (exception? x) one).

Comment by Alex Fowler [ 22/Nov/13 6:35 AM ]

Also, obviously I missed the (boolean? x) predicate in the original post. Did not even guess it is absent too until I occasionally got into it today. Currently the most clean way we have is to do (or (true? x) (false? x)). Needles to say, it looks weird next to the present (integer? x) or (float? x).

Comment by Brandon Bloom [ 22/Jul/14 1:02 AM ]

Predicates for core types are also very useful for portability to CLJS.

Comment by Brandon Bloom [ 22/Jul/14 1:05 AM ]

I'd be happy to provide a patch for this, but I'd prefer universal interface support where possible. Therefore, this ticket, in my mind, is behind http://dev.clojure.org/jira/browse/CLJ-803 etc.

Comment by Alex Miller [ 22/Jul/14 6:12 AM ]

I don't think it's worth making a ticket for this until Rich has looked at it and determined which parts are wanted.

Comment by Alex Miller [ 02/Dec/14 4:33 PM ]

Someone asked about a boolean? predicate, so throwing this one on the list...

Comment by Reid McKenzie [ 02/Dec/14 4:51 PM ]

uuid? maybe. UUIDs have a bit of a strange position in that we have special printer handling for them built into core implying that they are intentionally part of Clojure, but there is no ->UUID constructor and no functions in core that operate on them so I could see this one being specifically declined.

Comment by Brandon Bloom [ 03/May/15 2:50 PM ]

This has been troubling me again with my first cljc project. So, I've added a whole bunch of tickets (with patches!) for individual predicates in both CLJ and CLJS.

Comment by Alex Miller [ 03/May/15 5:35 PM ]

As I said above, I don't want to mess with specific patches or tickets on this until Rich gets a look at this and we decide which stuff should and should not be included. So I'm going to ignore your other tickets for now...





[CLJ-1295] Speed up dissoc on array-maps Created: 15/Nov/13  Updated: 29/Apr/15

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

Type: Enhancement Priority: Major
Reporter: Andy Fingerhut Assignee: Unassigned
Resolution: Unresolved Votes: 2
Labels: ft, performance

Attachments: File clj-1295-1.diff    
Patch: Code
Approval: Triaged

 Description   

In latest Clojure master as of Nov 15 2013, the method without() in PersistentArrayMap.java first searches for a matching key using indexOf(key) and saves the result in i.

If a matching key was found, the code then copies the old array to the new smaller one, but unnecessarily repeats the comparison of every key in the map to the key being removed, even though its location is already stored in i.

Screened by: Alex Miller



 Comments   
Comment by Andy Fingerhut [ 15/Nov/13 7:05 PM ]

The patch clj-1295-1.diff changes PersistentArrayMap's without() to use System.arraycopy to copy only the necessary parts from the current array to newArray, similar to PersistentHashMap's method removePair().

Benchmark 1 has strings for keys, which are relatively slow to compare to each other.

(def m1 (array-map "abcdef" 1 "abcdeg" 2 "abcdeh" 3 "abcdei" 4))
(time (dotimes [i 100000000] (dissoc m1 "abcdei")))

1.6.0-alpha2 with no changes:
"Elapsed time: 29663.443 msecs"
"Elapsed time: 29490.225 msecs"
"Elapsed time: 29600.138 msecs"
"Elapsed time: 29627.948 msecs"

1.6.0-alpha2 with patch clj-1295-1.diff:
"Elapsed time: 6362.006 msecs"
"Elapsed time: 6121.006 msecs"
"Elapsed time: 6163.377 msecs"
"Elapsed time: 6155.299 msecs"
"Elapsed time: 6395.224 msecs"

Averages about 21% of the run time before the change.

Benchmark 2 has keywords for keys, which are compared via Java ==, so as fast as comparison can get.

(def m2 (array-map :abcdef 1 :abcdeg 2 :abcdeh 3 :abcdei 4))
(time (dotimes [i 100000000] (dissoc m2 :abcdei)))

1.6.0-alpha2 with no changes:
"Elapsed time: 5033.863 msecs"
"Elapsed time: 5028.327 msecs"
"Elapsed time: 5045.019 msecs"
"Elapsed time: 5004.751 msecs"
"Elapsed time: 5039.143 msecs"

1.6.0-alpha2 with patch clj-1295-1.diff:
"Elapsed time: 2874.748 msecs"
"Elapsed time: 2862.878 msecs"
"Elapsed time: 2887.778 msecs"
"Elapsed time: 2874.196 msecs"
"Elapsed time: 2861.807 msecs"

Averages about 57% of the run time before the change.

Comment by Ghadi Shayban [ 08/Dec/14 9:47 AM ]

A nice boost, but probably obsoleted by CLJ-1517

Comment by Andy Fingerhut [ 08/Dec/14 11:10 AM ]

Always happy to be obsoleted by something even better

Comment by Ghadi Shayban [ 08/Dec/14 11:43 AM ]

I dunno, seems like CLJ-1517 phase 1 is just vectors not maps, so this is still easy low-hanging fruit.

Comment by Alex Miller [ 08/Dec/14 1:07 PM ]

There will be a second ticket for maps, both will be targeted for 1.8.





[CLJ-1293] Portable "catch-all" mechanism Created: 05/Nov/13  Updated: 28/Dec/14

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

Type: Enhancement Priority: Critical
Reporter: Brandon Bloom Assignee: Unassigned
Resolution: Unresolved Votes: 4
Labels: None

Attachments: Text File CLJ-1293-v001.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Design page: http://dev.clojure.org/display/design/Platform+Errors

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

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.



 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.





[CLJ-1290] clojure.xml parse docstring omits InputSource Created: 01/Nov/13  Updated: 12/Mar/15

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

Type: Enhancement Priority: Minor
Reporter: Phill Wolf Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: docstring, newbie, xml

Attachments: Text File CLJ-1290.patch    
Patch: Code
Approval: Triaged

 Description   

The clojure.xml parse docstring mentions that parameter s "can be a File, InputStream or String naming a URI." But those choices do not cover a common case, parsing the value of a String. Actually, parse also allows InputSource, which solves the problem. The docstring should mention InputSource (or clarify its omission, if not inadvertent).

user> (use '[clojure.xml :as xml])
nil
user> (import '[java.io StringReader])
java.io.StringReader
user> (import '[org.xml.sax InputSource])
org.xml.sax.InputSource
user> (xml/parse (InputSource. (StringReader. "<egg>green</egg>")))
{:tag :egg, :attrs nil, :content ["green"]}

Approach: Update doc-string to reflect that s also can be an InputSource
Patch: CLJ-1290.patch
Screened by:



 Comments   
Comment by Édipo L Féderle [ 15/Sep/14 3:57 PM ]

You and mean that de (doc xml/parse) should include also "can be a xml String" ?
I don't know if I understand you right.
Thanks.

Comment by Phill Wolf [ 24/Sep/14 6:06 AM ]

InputSource is the use of xml/parse that is not encompassed by the docstring:

(xml/parse (InputSource. (StringReader. "<egg>green</egg>")))

Perhaps xml/parse aimed to hide InputSource by making specific provision for some of InputSource's capabilities. But reading a String is important, and xml/parse does not accept a StringReader, so InputSource remains important.





[CLJ-1289] aset-* and aget perform poorly on multi-dimensional arrays even with type hints. Created: 01/Nov/13  Updated: 14/Feb/14

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

Type: Enhancement Priority: Major
Reporter: Michael O. Church Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: arrays, performance
Environment:

Clojure 1.5.1.

Dependencies: criterium


Attachments: Text File CLJ-1289-p1.patch    
Patch: Code
Approval: Triaged

 Description   

Here's a transcript of the behavior. I don't know for sure that reflection is being done, but the performance penalty (about 1300x) suggests it.

user=> (use 'criterium.core)
nil
user=> (def b (make-array Double/TYPE 1000 1000))
#'user/b
user=> (quick-bench (aget ^"[[D" b 304 175))
WARNING: Final GC required 3.5198021166354323 % of runtime
WARNING: Final GC required 29.172288684474303 % of runtime
Evaluation count : 63558 in 6 samples of 10593 calls.
             Execution time mean : 9.457308 µs
    Execution time std-deviation : 126.220954 ns
   Execution time lower quantile : 9.344450 µs ( 2.5%)
   Execution time upper quantile : 9.629202 µs (97.5%)
                   Overhead used : 2.477107 ns

One workaround is to use multiple agets.

user=> (quick-bench (aget ^"[D" (aget ^"[[D" b 304) 175))
WARNING: Final GC required 40.59820310542545 % of runtime
Evaluation count : 62135436 in 6 samples of 10355906 calls.
             Execution time mean : 6.999273 ns
    Execution time std-deviation : 0.112703 ns
   Execution time lower quantile : 6.817782 ns ( 2.5%)
   Execution time upper quantile : 7.113845 ns (97.5%)
                   Overhead used : 2.477107 ns

Cause: The inlined version only applies to arity 2, and otherwise it reflects.



 Comments   
Comment by Gary Fredericks [ 08/Dec/13 9:28 PM ]

A glance at the source makes it obvious that the hypothesis is correct – the inlined version only applies to arity 2, and otherwise it reflects.

I thought this would be as simple as converting the inline function to be variadic (using reduce), but after trying it I realized this is tricky as you have to generate the correct type hints for each step. E.g., given ^"[[D" the inline function needs to type-hint the intermediate result with ^"[D". This isn't difficult if we're just dealing with strings that begin with square brackets, but I don't know for sure that those are the only possibilities.

Comment by Yaron Peleg [ 13/Feb/14 4:44 AM ]

Bump. I just got bitten bad by this.

There are two seperate issues here:
1) (aget 2d-array-doubles 0 0 ) doesn't emit a reflection warning.
2) It seems like the compiler has enough information to avoid the reflective call here.

Note this gets exp. worse as number of dimensions grows, i.e (get doubles3d 0 0 0)
will be 1M slower, etc' Not true, unless you iterate over all elements. it's
simply n_dims*1000x per lookup.

Nasty surprise, especially considering you often go to primitive arrays for speed,
and a common use case is an inner loop(s) that iterate over arrays.

Comment by Gary Fredericks [ 13/Feb/14 7:08 AM ]

I can probably take a stab at this.

Comment by Gary Fredericks [ 13/Feb/14 8:34 PM ]

I think the reflection warning problem is pretty much impossible to solve without changing code elsewhere in the compiler, because the reflection done in aget is a different kind than normal clojure reflection – it's explicitly in the function body rather than emitted by the compiler. Since the compiler isn't emitting it, it doesn't reasonably know it's even there. So even if aget is fixed for other arities, you still won't get the warning when it's not inlined.

I can imagine some sort of metadata that you could put on a function telling the compiler that it will reflect if not inlined. Or maybe a more generic not-inlined warning?

The global scope of adding another compiler flag seems about balanced by the seriousness of array functions not being able to warn on reflection.

Comment by Gary Fredericks [ 13/Feb/14 8:52 PM ]

Attached CLJ-1289-p1.patch which simply inlines variadic calls to aget. It assumes that if it sees a :tag on the array arg that is a string beginning with [, it can assume that the return value from one call to aget can be tagged with the same string with the leading [ stripped off.

I'm not a jvm expert, but having read through the spec a little bit I think this is a reasonable assumption.

Comment by Alex Miller [ 14/Feb/14 3:34 PM ]

I think this probably is actually true, but a more official way to ask that question would be to get the array class and ask for Class.getComponentType() (and less janky than string munging).

Comment by Gary Fredericks [ 14/Feb/14 3:40 PM ]

How would you get the array class based on the :tag type hint?

Comment by Gary Fredericks [ 14/Feb/14 7:05 PM ]

I see (-> s (Class/forName) (.getComponentType) (.getName)) does the same thing – is that route preferred, or is there another one?





[CLJ-1282] The quote special form should throw an exception if passed more than one form to quote Created: 23/Oct/13  Updated: 13/Jul/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: 5
Labels: errormsgs, ft, reader

Attachments: Text File CLJ-1282-p1.patch     Text File CLJ-1282-p2.patch    
Patch: Code and Test
Approval: Triaged

 Description   

Quote currently ignores all but the first argument. In the case of being called accidentally with multiple values, it should throw an exception specifying the error.

user> (quote 1 2 3)
1

Patch: CLJ-1282-p2.patch

Screened by: Alex Miller

------- Original: --------

Every once in a while, you can just go down the rabbit hole.

I had an errant expression in my code:

(-> message get-message-values 'DESTINATION_MERCHANT_ID)

One would think this would work; it certainly would if the key was a keyword and not a symbol.

One would expect this to expand to:

('DESTINATION_MERCHANT_ID (get-message-values message))

however, the reader is involved, so it is as if the source were:

(-> message get-message-values (quote DESTINATION_MERCHANT_ID))

which expands to:

(quote (-> message get-message-values) DESTINATION_MERCHANT_ID))

... hilarity ensues! Because quote currently ignores extra parameters, my code gets the quoted value '(clojure.core/-> message get-message-values) rather than the expected string from the map; this shifts us from the "there's a bug in my code" to "the nature of reality is broken".

The correct expression is:

(-> message get-message-values (get 'DESTINATION_MERCHANT_ID))

This took quite a while to track down; if the

special form checked that it was passed exactly one form to quote and threw an exception otherwise, I think I would have caught this much earlier. It could even identify the expression it is quoting, which would provide a lot better understanding of where I went wrong.



 Comments   
Comment by Howard Lewis Ship [ 23/Oct/13 2:02 PM ]

Sorry, can't edit the description now to correct the formatting errors.

Comment by Howard Lewis Ship [ 24/Oct/13 6:09 PM ]

I just wanted to point out that your description is shorter, but makes it appear that such a use is unlikely and therefore unimportant; the detail of my description is to point out a reasonable situation where something explicable, but completely counterintuitive and confusing, does occur.

Comment by Alex Miller [ 24/Oct/13 8:28 PM ]

That's why I left the original in there too.

Comment by Gary Fredericks [ 09/Dec/13 7:07 AM ]

(quote) currently returns nil. Do we have an opinion about that?

Comment by Gary Fredericks [ 09/Dec/13 9:32 AM ]

Attached p1, which throws an IllegalArgumentException (wrapped in a CompilerException of course) for anything but 1 arg, and includes the number of args that were passed.

I can't think of any reason why (quote) would be useful, so I decided to throw on that too. Very easy to change of course.

Also added a test that (eval '(quote 1 2 3)) throws.

Comment by Stuart Halloway [ 31/Jan/14 12:46 PM ]

I recommend the following changes:

  • throw an ex-info that includes the offending form in its map {:form ...}
  • check only for the map data, not exception type or message, in the tests
Comment by Andy Fingerhut [ 31/Jan/14 6:31 PM ]

Patch CLJ-1282-p1.patch no longer applies cleanly after commits made to Clojure master on Jan 31 2014, probably due to the patch committed for CLJ-1318, and probably only because some lines of context changed in the test file. That would be trivial to update, but Stu's comments above suggest that more significant changes need to be made.

Comment by Gary Fredericks [ 01/Feb/14 9:19 AM ]

Throwing an ex-info is easy enough. I don't know how to avoid at least incidentally checking for the exception type, since the ExceptionInfo is wrapped in a CompilerException. I'll make a patch that keeps the class name in the test but doesn't do any checks on the cause aside from the ex-data. Let me know if I should do anything different.

Comment by Gary Fredericks [ 01/Feb/14 9:58 AM ]

Attached CLJ-1282-p2.patch which is off of the current master and addresses Stu's points.

Comment by Alex Miller [ 04/Feb/14 11:23 PM ]

Moving back to Triaged for more looks.

Comment by Nicola Mometto [ 16/Feb/14 12:12 PM ]

Currently (quote) returns nil, is it intended that this patch makes that an error or was this by accident?

Comment by Gary Fredericks [ 16/Feb/14 12:23 PM ]

I consciously chose to make (quote) an error – I made a comment about that earlier and didn't get any feedback, so I unilaterally decided to make it an error due to the fact that I couldn't think of any possible use for (quote).

It's an easy switch if somebody thinks differently.

Comment by Nicola Mometto [ 16/Feb/14 1:13 PM ]

I'm sorry I did not notice your previois comment.
I'm asking because I need to know whether I should throw on (quote) for tools.analyzer, currently it is allowed but I too think that (quote) should be an error.

Comment by Alex Miller [ 29/Apr/15 11:51 AM ]

I also think (quote) should throw an error.

Comment by Stuart Halloway [ 13/Jul/15 5:35 PM ]

This is an API change request, not a defect, and the change recommended here could break (admittedly ill-advised) programs.





[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-1277] Speed up printing of time instants by adding type hints Created: 10/Oct/13  Updated: 03/Oct/14

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

Type: Enhancement Priority: Major
Reporter: Andy Fingerhut Assignee: Unassigned
Resolution: Unresolved Votes: 1
Labels: ft, performance

Attachments: Text File clj-1277-1.txt    
Patch: Code
Approval: Triaged

 Description   

There are several occurrences of reflection in instant.clj that slow down the printing of time instants.

Clojure Google group conversation link: https://mail.google.com/mail/u/0/?shva=1#label/clojure/1419e1e6f6cc5b3d

The addition of a few type hints is enough to speed the printing of time instants by a factor of about 3 to 4.5, in a few small benchmarks.

Patch: clj-1277-1.txt
Screened by: Alex Miller



 Comments   
Comment by Andy Fingerhut [ 10/Oct/13 12:07 AM ]

Patch clj-1277-1.txt adds 4 type hints that eliminate all reflection occurrences in source file instant.clj. Benchmarks show that it speeds up printing of java.util.Date and java.sql.Timestamp objects by a factor of about 3 to 4.5.

Latest Clojure master as of Oct 9 2013:

user=> (time (let [d (java.util.Date.)] (dotimes [i 3000000] (pr-str d))))
"Elapsed time: 24094.282 msecs"
user=> (import 'java.sql.Timestamp)
user=> (time (let [d (java.sql.Timestamp. 1300000000000)] (dotimes [i 2000000] (pr-str d))))
"Elapsed time: 20856.957 msecs"

That version of Clojure plus the patch clj-1277-1.txt:

user=> (time (let [d (java.util.Date.)] (dotimes [i 3000000] (pr-str d))))
"Elapsed time: 5085.847 msecs"
user=> (time (let [d (java.sql.Timestamp. 1300000000000)] (dotimes [i 2000000] (pr-str d))))
"Elapsed time: 7582.233 msecs"

Comment by Alexander Kiel [ 10/Oct/13 4:54 AM ]

Thanks for the patch Andy. But I don't like the (set! warn-on-reflection true). I think its better to use it only in the dev profile in leiningen. Not in real production code.

Comment by Andy Fingerhut [ 10/Oct/13 4:06 PM ]

Alexander, Leiningen is not used for building Clojure itself. The two supported choices are Maven and ant. Several Clojure source files, e.g. core/protocols.clj and core/reducers.clj, set warn-on-reflection to true, I believe so that if code is changed in such a way as to introduce a warning, it will be caught more quickly.

If the screeners or Rich think it is inappropriate, it is easy enough to remove.

Comment by Alex Miller [ 10/Oct/13 4:48 PM ]

Setting that is not uncommon in core clojure code and seems fine to me here.





[CLJ-1259] Speed up pprint Created: 09/Sep/13  Updated: 04/May/15

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

Type: Enhancement Priority: Major
Reporter: Andy Fingerhut Assignee: Unassigned
Resolution: Unresolved Votes: 1