Vetted (Clojure JIRA)

[CLJ-1125] Clojure can leak memory when used in a servlet container

Fri, 14 Jun 2013 10:56:13 -0500

When used within a servlet container
(Jetty/Tomcat/JBossAS/Immutant/etc), the thread locals Var.dvals (used
to store dynamic bindings) and LockingTransaction.transaction (used to
store the currently active transaction(s)) prevent all of the classes
loaded by an application's clojure runtime from being garbage collected,
resulting in a memory leak.

The issue comes from threads living beyond the lifetime of a
deployment - servlet containers use thread pools that are shared
across all applications within the container. Currently, the dvals and
transaction thread locals are not discarded when they are no longer
needed, causing their contents to retain a hard reference to their
classloaders, which, in turn, causes all of the classes loaded under
the application's classloader to be retained until the thread exits
(which is generally at JVM shutdown).

I've attached a patch that does the following:

Var.dvals is now removed when the thread bindings are popped
Var.dvals no longer has an initialValue, so checking to see if it is
set will no longer set it to an empty Frame
The outer transaction in LockingTransaction.transaction now removes
the thread local when it is finished

There is still the opportunity for memory leaks if agents or futures
are used, and the executors used for them are not shutdown when the
app is undeployed. That's a solvable problem, but should probably be
solved by the containers themselves (and/or the war generation tools)
instead of in clojure itself.

This patch has a small performance impact: its use of a try/finally
around running transactions to remove the outer transaction adds
4-6 microseconds to each transaction call on my hardware.

Providing an automated test for this patch is difficult - I've tested
it locally with repeated deployments to a container while monitoring
GC and permgen. All of clojure's tests pass with it applied.

The above is a condensation of:
https://groups.google.com/d/topic/clojure-dev/3CXDe8_9G58/discussion

I'm happy to provide whatever feedback/work is needed to get this
applied.

[CLJ-1184] Evaling #{do ...} or [do ...] is treated as the do special form

Sun, 9 Jun 2013 16:31:55 -0500

Evaluating a persistent collection for which the function 'first' returns the symbol 'do' leads to that collection being treated as the do special form, even though it may be a vector or even a set. IMHO, the expected result would be to report that 'do' cannot be resolved. For the cause, see the if condition on line 6604 of Compiler.java in clojure-1.5.1.

E.g.:
[do 1 2]
;=> 2

#{"hello" "goodbye" do}
;=> "hello"
; Wat?

[CLJ-1083] Incorrect ArityException message for function names containing ->

Fri, 7 Jun 2013 14:01:34 -0500

user=> (defn a->b [])
#'user/a->b
user=> (a->b 1)
ArityException Wrong number of args (1) passed to: user$a clojure.lang.AFn.throwArity (AFn.java:437)

Note that the reported function name in the stack trace is "user$a", where it should be "user$a->b" (or some mangled variant thereof?)

See discussion here: https://groups.google.com/d/msg/clojure/PVNoLclhhB0/_NWqyE0cPAUJ

[CLJ-787] transient blows up when passed a vector created by subvec

Tue, 28 May 2013 11:50:25 -0500

Subvectors created with subvec from a PersistentVector cannot be made transient:

user=> (transient (subvec [1 2 3 4] 2))
ClassCastException clojure.lang.APersistentVector$SubVector cannot be cast to clojure.lang.IEditableCollection  clojure.core/transient (core.clj:2864)

[CLJ-1202] protocol fns with dashes may get compiled into property access when used higher order

Fri, 10 May 2013 15:19:29 -0500

user=> (defprotocol Foo (-foo [x]))
Foo
user=> (deftype Bar [] Foo (-foo [_] :baz))
user.Bar
user=> (map -foo [(Bar.)])
IllegalArgumentException No matching field found: foo for class user.Bar  
clojure.lang.Reflector.getInstanceField (Reflector.java:271)

I would have expected to see (:baz). The full stack is:

IllegalArgumentException No matching field found: foo for class user.Bar
	clojure.lang.Reflector.getInstanceField (Reflector.java:271)
	clojure.lang.Reflector.invokeNoArgInstanceMember (Reflector.java:300)
	user/eval79/fn--80/G--71--82 (NO_SOURCE_FILE:11)
	user/eval79/fn--80/G--70--85 (NO_SOURCE_FILE:11)
	clojure.core/map/fn--4207 (core.clj:2485)
	clojure.lang.LazySeq.sval (LazySeq.java:42)
	clojure.lang.LazySeq.seq (LazySeq.java:60)
	clojure.lang.RT.seq (RT.java:484)
	clojure.core/seq (core.clj:133)
	clojure.core/print-sequential (core_print.clj:46)
	clojure.core/fn--5406 (core_print.clj:143)
	clojure.lang.MultiFn.invoke (MultiFn.java:231)
nil

I suspect this is somehow related to the property access changes to make Clojure/ClojureScript compatible. I was in fact prepping core.logic for a unified code base and was adopting the ClojureScript protocol naming convention when I encountered this issue.

~~CLJ-872~~ added dash property support to Clojure.

[CLJ-124] GC Issue 120: Determine mechanism for controlling automatic shutdown of Agents, with a default policy and mechanism for changing that policy as needed

Fri, 12 Apr 2013 09:52:24 -0500

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

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

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

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

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

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

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

- would be bound by default to true

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

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

------

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

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

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

[CLJ-1058] StackOverflowError on exception in reducef for PersistentHashMap fold

Fri, 12 Apr 2013 09:42:02 -0500

If reducef throws an exception, the PHM fold code can descend into an infinite loop, causing a stack overflow which masks the problem. This situation is commented "aargh" in PersistentHashMap.java line 444 (as of 412a51d).

To reproduce:

user> (require '[clojure.core.reducers :as r])
nil
user> (r/fold (fn ([]) ([ret k v] (+ 3 "foo") ret)) (into {} (map (juxt identity identity) (range 10000))))
;; boom

This results in a stack like: https://raw.github.com/gist/3bab917287a7fd635a84/f38bfe3e270556e467f3fc02062af7ea10781390/gistfile1.txt

[CLJ-420] Some compiler exceptions erroneously using REPL line numbers.

Fri, 12 Apr 2013 09:42:02 -0500

Certain kinds of errors in loaded source files are coming back tagged with the correct source file, but what seems to be the REPL line number.

http://groups.google.com/group/clojure/browse_frm/thread/beb36e7228eabd69/a7ef16dcc45834bc?hl=en#a7ef16dcc45834bc

jawolfe@[~/Projects/testproj]: cat > src/test.clj

bla
jawolfe@[~/Projects/testproj]: cat > src/test2.clj

(bla)
jawolfe@[~/Projects/testproj]: lein repl
user=> (require 'test)
java.lang.Exception: Unable to resolve symbol: bla in this context
(test.clj:1)
user=> (require 'test)a
java.lang.Exception: Unable to resolve symbol: bla in this context
(test.clj:2)
user=> (require 'test)
java.lang.Exception: Unable to resolve symbol: bla in this context
(test.clj:3)
user=> (require 'test2)
java.lang.Exception: Unable to resolve symbol: bla in this context
(test2.clj:2)
user=> (require 'test2)
java.lang.Exception: Unable to resolve symbol: bla in this context
(test2.clj:2)
user=> (require 'test2)
java.lang.Exception: Unable to resolve symbol: bla in this context
(test2.clj:2)
user=> (require 'test)
java.lang.Exception: Unable to resolve symbol: bla in this context
(test.clj:7)
user=>

[CLJ-1105] defrecord classes implement IPersistentCollection but not .empty, clojure.walk assumes collections support empty

Fri, 12 Apr 2013 09:42:00 -0500

Using clojure.walk functions fails surprisingly for data containing records defined with defrecord:

user=> (defrecord Foo [x])
user.Foo
user=> (def f (Foo. :x))
#'user/f
user=> (use 'clojure.walk)
nil
user=> (postwalk identity {:foo f})
UnsupportedOperationException Can't create empty: user.Foo user.Foo (NO_SOURCE_FILE:1)

This seems to be because clojure.walk/walk guards a call to (empty form) with a (coll? form) check. The check succeeds because records implement IPersistentCollection, but (empty form) throws an exception. This looks to me like a bug in clojure.walk (it should check records separately and either treat them as atomic or implement a way of walking through them) but perhaps it is a sign of some unclarity in the contract of collections.

[CLJ-701] Compiler loses 'loop's return type in some cases

Fri, 12 Apr 2013 09:42:00 -0500

(set! *warn-on-reflection* true)
(fn [] (loop [b 0] (recur (loop [a 1] a))))

Generates the following warnings:

recur arg for primitive local: b is not matching primitive, had: Object, needed: long
Auto-boxing loop arg: b

This is interesting for several reasons. For one, if the arg to recur is a let form, there is no warning:

(fn [] (loop [b 0] (recur (let [a 1] a))))

Also, the compiler appears to understand the return type of loop forms just fine:

(use '[clojure.contrib.repl-utils :only [expression-info]])
(expression-info '(loop [a 1] a))
;=> {:class long, :primitive? true}

The problem can of course be worked around using an explicit cast on the loop form:

(fn [] (loop [b 0] (recur (long (loop [a 1] a)))))

Reported by leafw in IRC: http://clojure-log.n01se.net/date/2011-01-03.html#10:31

[CLJ-1154] Compile.java closes out preventing java from reporting exceptions

Fri, 12 Apr 2013 09:31:03 -0500

I was trying to compile a project that has some native dependencies. I am using clojure-maven-plugin version 1.3.13 with Maven 2.0. I forgot to set java.library.path properly so that the native library could be found, and only got an error of

[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Clojure failed.
[INFO] ------------------------------------------------------------------------

I traced this down to Compile.java, where it is flushing and closing

out

in the finally block. The JVM uses out to write out a stack trace for any uncaught exceptions. When out is closed it is unable to write out the stack trace for the UnsatisfiedLinkError that was being thrown. This made it very difficult to debug what was happening.

[CLJ-823] Piping seque into seque can deadlock

Fri, 12 Apr 2013 09:23:49 -0500

I'm not sure if this is a supported scenario, but the following deadlocks in Clojure 1.3:

(let [xs (seque (range 150000))
ys (seque (filter odd? xs))]
(apply + ys))

As I understand it, the problem is that ys' fill takes place on an agent thread, so when it calls xs' drain, the (send-off agt fill) does not immediately trigger xs' fill, but is instead put on the nested list to be performed when ys' agent returns. Unfortunately, ys' fill will eventually block trying to take from xs, and so it never returns and the pending send-offs are never sent. Wrapping the send-off in drain to:

(future (send-off agt fill))

is a simple (probably not optimal) way to fix the deadlock.

[CLJ-1157] Classes generated by gen-class aren't loadable from remote codebase for mis-implementation of static-initializer

Fri, 12 Apr 2013 09:19:05 -0500

When a client program uses a remote service which uses RMI, and the service returns a object which created with gen-class with clojure as the return value, the return value is not loadable at client side.

At client side, a following exeption will be thrown.

Exception in thread "main" java.lang.ExceptionInInitializerError
        at java.io.ObjectStreamClass.hasStaticInitializer(Native Method)
        at java.io.ObjectStreamClass.computeDefaultSUID(ObjectStreamClass.java:1723)
        at java.io.ObjectStreamClass.access$100(ObjectStreamClass.java:69)
        at java.io.ObjectStreamClass$1.run(ObjectStreamClass.java:247)
        at java.io.ObjectStreamClass$1.run(ObjectStreamClass.java:245)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.io.ObjectStreamClass.getSerialVersionUID(ObjectStreamClass.java:244)
        at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:600)
        at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1601)
        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1514)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1750)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1347)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)
        at sun.rmi.server.UnicastRef.unmarshalValue(UnicastRef.java:324)
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:173)
        at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:194)
        at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:148)
        at $Proxy0.getResult(Unknown Source)
        at client.SampleClient$_main.doInvoke(SampleClient.clj:12)
        at clojure.lang.RestFn.invoke(RestFn.java:397)
        at clojure.lang.AFn.applyToHelper(AFn.java:159)
        at clojure.lang.RestFn.applyTo(RestFn.java:132)
        at client.SampleClient.main(Unknown Source)
 Caused by: java.io.FileNotFoundException: Could not locate remoteserver/SampleInterfaceImpl__init.class or remoteserver/SampleInterfaceImpl.clj on classpath: 
        at clojure.lang.RT.load(RT.java:434)
        at clojure.lang.RT.load(RT.java:402)
        at clojure.core$load$fn__5039.invoke(core.clj:5520)
        at clojure.core$load.doInvoke(core.clj:5519)
        at clojure.lang.RestFn.invoke(RestFn.java:408)
        at clojure.lang.Var.invoke(Var.java:415)
        at remoteserver.SampleInterfaceImpl.<clinit>(Unknown Source)
        ... 23 more

HOW TO REPRODUCT THIS ISSUE

If you want to see this issue at your computer, clone my example project from my github.

git clone git://github.com/tyano/clojure_genclass_fix.git

and build them (You must have installed Leiningen 2):

cd clojure_genclass_fix
sh build.sh

start rmiregistry:

rmiregistry &

start remoteserver:

cd remoteserver
sh start.sh

You will see a message "Server ready. " or "Server ready. (rebind)".

At last, start client program:

cd ../client
sh start.sh

Without my patch, you will see a same Exception described above. But with clojure with my patch, you will see a right response message: "response = this is sample."

THE REASON

The reason of this problem is in bytecodes generated by gen-class. A gen-classed class (in this case, SampleInterfaceImpl.class) uses a static-initializer for loading SampleInterfaceImpl__init.class (which load other classes which implements functions in the class). The static-initializer is like bellow: (the following code is decompiled with JD - http://java.decompiler.free.fr/?q=jdgui )

static
  {
    RT.var("clojure.core", "load").invoke("/remoteserver/SampleInterfaceImpl");
  }

Very simple code. it seems non-problematic. But RT.load changes the classloader for loading __init.class in the processing! RT.load in default uses a context-classloader for loading classes. But all classes depending on a gen-classed class must be loaded a same classloader with a main gen-classed class. In this case, RT.load must use a remote URLClassLoader which load a main class.

So, gen-class must be create bytecodes that is same with the following java code.

static
  {
    Var.pushThreadBindings(RT.map(new Object[] { Compiler.LOADER, SampleInterfaceImpl.class.getClassLoader() }));
    try {
        RT.var("clojure.core", "load").invoke("/remoteserver/SampleInterfaceImpl");
    }
    finally 
    {
        Var.popThreadBindings();
    }
  }

With this code, RT.load will uses a same classloader which load SampleInterfaceImpl.class.
My patch for gen-class will create bytecodes equal to the above example.

You can use an attached patch '20130204_fix_classloader.diff', or pull 'fix_classloader' branch from my github repositry ( git@github.com:tyano/clojure.git ).

[CLJ-348] reify allows use of qualified name as method parameter

Fri, 1 Mar 2013 12:33:02 -0600

This should complain about using a fully-qualified name as a parameter:

(defmacro lookup []
`(reify clojure.lang.ILookup
(valAt [_ key])))

Instead it simply ignores that parameter in the method body in favour of clojure.core/key.

[CLJ-1073] Make print-sequential interruptible

Fri, 1 Mar 2013 10:18:01 -0600

This allows print-sequential to be interrupted by Thread.interrupt(), rather than requiring clients to resort to Thread.stop(). This is especially helpful when printing very large sequences.

See also clojure-dev discussion at https://groups.google.com/d/topic/clojure-dev/vs0RNUQXiYE/discussion

[CLJ-1100] Reader literals cannot contain periods

Thu, 14 Feb 2013 15:04:53 -0600

The LispReader tries to read a record instead of a literal if the tag contains periods:

https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/LispReader.java#L1171

Which effectively means that reader tags cannot contain periods.
The EDN spec is unclear on this:

edn supports extensibility through a simple mechanism. # followed immediately by a symbol starting with an alphabetic character indicates that that symbol is a tag.

(issue opened: https://github.com/edn-format/edn/issues/39)

If periods are allowed, then the LispReader should first check to see if the tag is in *data-readers* and only then if not try to initialize a Java class.

I'm happy to write the patch if this behavior is what is desired.

[CLJ-1082] Subvecs of primitive vectors cannot be reduced

Sat, 26 Jan 2013 07:29:55 -0600

I could reproduce on current 10/05 git.

Reduce doesn't work on subvecs of primitive vectors.
Root cause seems to be that RT/subvec and APersistentVector$SubVector make assumptions about implementation

If reduce on a subvec doesn't work then neither will nice ops like fold.

How to cause:

(let [prim-vec (into (vector-of :long) (range 10000))]
(reduce + (subvec prim-vec 1 500)))

->> ClassCastException clojure.core.Vec cannot be cast to clojure.lang.PersistentVector clojure.lang.APersistentVector$SubVector.iterator (APersistentVector.java:523)

[CLJ-1033] pr-str and read-string don't handle @ symbols inside keywords properly

Sun, 13 Jan 2013 22:58:37 -0600

user=> (read-string (pr-str {(keyword "key@other") :stuff}))
RuntimeException Map literal must contain an even number of forms  clojure.lang.Util.runtimeException (Util.java:170)

pr-str emits "{:key@other :stuff}", which read-string fails to interpret correctly. Either pr-str needs to escape the @ symbol, or read-string needs to handle the symbol inside a keyword.

Background: I'm passing a map with email addresses as keys through Storm bolts, which require a thrift-serializable form. Using the pr-str/read-string combo fails on these keys, so I've fallen back to JSON serialization.

[CLJ-1104] Concurrent with-redefs do not unwind properly, leaving a var permanently changed

Fri, 21 Dec 2012 23:05:10 -0600

On 1.4 and latest master:

user> (defn ten [] 10)
#'user/ten
user> (doall (pmap #(with-redefs [ten (fn [] %)] (ten)) (range 20 100)))
(20 21 22 23 24 25 34 27 28 29 30 31 32 33 34 35 36 37 38 39 39 35 42 43 44 45 48 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 79 87 88 89 90 91 92 93 94 95 97 92 98 99)
user> (ten)
79

Not sure if this is a bug per se, but the doc doesn't mention lack of concurrency safety and my expectation was that the original value would always be restored after any (arbitrarily interleaved) sequence of with-redefs calls.

[CLJ-1059] PersistentQueue doesn't implement java.util.List, causing nontransitive equality

Tue, 11 Dec 2012 13:58:01 -0600

PersistentQueue implements Sequential but doesn't implement java.util.List. Lists form an equality partition, as do Sequentials. This means that you can end up with nontransitive equality:

(def q (conj clojure.lang.PersistentQueue/EMPTY 1 2 3))
;=> #user/q
(def al (doto (java.util.ArrayList.) (.add 1) (.add 2) (.add 3)))
;=> #user/al
(def v [1 2 3])
;=> #user/v
(= al v)
;=> true
(= v q)
;=> true
(not= al q)
;=> true

This happens because PersistentQueue is a Sequential but not a List, ArrayList is a List but not a Sequential, and PersistentVector is both.

[CLJ-1102] Better handling of exceptions with empty stack traces

Fri, 30 Nov 2012 14:57:46 -0600

I don't know what I did to cause some exceptions to be thrown while running Clojure tests that return a length 0 array from (.getStackTrace throwable), but according to the Java docs this is legal. I searched all places in the Clojure code that call .getStackTrace and found two that don't handle this correctly, one of which causes an ArrayOutOfBoundsException (that is the one I found during my testing).

[CLJ-1090] Indirect function calls through Var instances fail to clear locals

Fri, 30 Nov 2012 14:26:45 -0600

If you make a function call indirectly by invoking a Var object (which derefs itself and invokes the result), the invocation parameters remain in the thread's local stack for the duration of the function call, even though they are needed only long enough to be passed into the deref'd function. As a result, passing a lazy seq into a function invoked in its Var form may run out of memory if the seq is forced inside that function. For example:

(defn total [xs] (reduce + 0 xs))
(total (range 1000000000)) ; this works, though takes a while
(#'total (range 1000000000)) ; this dies with out of memory error

I can provide a patch if it would be useful. The fix should be trivial, something along the lines of wrapping each argN in clojure/lang/Var.java inside a Util.ret1(argN, argN = null) as is done in RestFn.java.

[CLJ-1056] defprotocol: invalid method overload syntax getting accepted

Thu, 29 Nov 2012 16:03:11 -0600

The compiler accepts both of these erroneous forms which while silly, are not imposible to come up with.

(defprotocol Foo (f ([this]) ([this arg])))
(defprotocol Bar (m [this]) (m [this arg]))

[CLJ-992] `iterate` reducer

Fri, 12 Oct 2012 08:10:52 -0500

Added a reducer implementation mirroring clojure.core/iterate.

[CLJ-1039] Using 'def with metadata {:type :anything} throws ClassCastException

Fri, 10 Aug 2012 13:40:31 -0500

In lein 1.7.1 (and CCW) the form (def ^{:type :anything} mydef 1) throws "ClassCastException clojure.lang.Var cannot be cast to clojure.lang.IObj clojure.core/with-meta (core.clj:211)".
This seems to be due to setting the :type metadata. With other metadata keys it works well.

If it is intended to forbid setting the :type metadata, then there should be an appropriate error message instead of the ClassCastException

In lein2 repl which is using "REPL-y 0.1.0-beta8" the exception does not occur.

Full stacktrace:
java.lang.ClassCastException: clojure.lang.Var cannot be cast to clojure.lang.IObj
at clojure.core$with_meta.invoke (core.clj:211)
clojure.core$vary_meta.doInvoke (core.clj:617)
clojure.lang.RestFn.invoke (RestFn.java:425)
clojure.core/fn (core_print.clj:76)
clojure.lang.MultiFn.invoke (MultiFn.java:167)
clojure.core$pr_on.invoke (core.clj:3266)
clojure.core$pr.invoke (core.clj:3278)
clojure.lang.AFn.applyToHelper (AFn.java:161)
clojure.lang.RestFn.applyTo (RestFn.java:132)
clojure.core$apply.invoke (core.clj:601)
clojure.core$prn.doInvoke (core.clj:3311)
clojure.lang.RestFn.invoke (RestFn.java:408)
clojure.main$repl$read_eval_print__6405.invoke (main.clj:246)
clojure.main$repl$fn__6410.invoke (main.clj:266)
clojure.main$repl.doInvoke (main.clj:266)
clojure.lang.RestFn.invoke (RestFn.java:512)
user$eval27$acc_3261auto__30$fn_32.invoke (NO_SOURCE_FILE:1)
clojure.lang.AFn.run (AFn.java:24)
java.lang.Thread.run (Thread.java:662)

[CLJ-731] Create macro to variadically unroll a combinator function definition

Fri, 28 Jan 2011 09:40:05 -0600

Clojure contains a set of combinators that are implemented in a similar, but slightly different way. That is, they are implemented as a complete set of variadic overloads on both the call-side and also on the functions that they return. Visually, they all tend to look something like:

(defn foo
  ([f]
     (fn
       ([] do stuff...)
       ([x] do stuff...)
       ([x y] do stuff...)
       ([x y z] do stuff...)
       ([x y z & args] do variadic stuff...)))
  ([f1 f2]
     (fn
       ([] do stuff...)
       ([x] do stuff...)
       ([x y] do stuff...)
       ([x y z] do stuff...)
       ([x y z & args] do variadic stuff...)))
  ([f1 f2 f3]
     (fn
       ([] do stuff...)
       ([x] do stuff...)
       ([x y] do stuff...)
       ([x y z] do stuff...)
       ([x y z & args] do variadic stuff...)))
  ([f1 f2 f3 & fs]
     (fn
       ([] do stuff...)
       ([x] do stuff...)
       ([x y] do stuff...)
       ([x y z] do stuff...)
       ([x y z & args] do variadic stuff...))))

To build this type of function for each combinator is tedious and error-prone.

There must be a way to implement a macro that takes a "specification" of a combinator including:

1. name
2. docstring
3. do stuff template
4. do variadic stuff template

And builds something like the function foo above. This macro should be able to implement the current batch of combinators (assuming that http://dev.clojure.org/jira/browse/CLJ-730 is completed first for the sake of verification).

[CLJ-47] GC Issue 43: Dead code in generated bytecode

Fri, 8 Oct 2010 10:21:00 -0500

Reported by Levente.Santha, Jan 11, 2009
The bug was described in detail in this thread: http://groups.google.com/
group/clojure/browse_thread/thread/81ba15d7e9130441

For clojure.core$last__2954.invoke the correct bytecode would be (notice 
the removed "goto    65" after "41:  goto    0"):

public java.lang.Object invoke(java.lang.Object)   throws 
java.lang.Exception;
  Code:
   0:   getstatic       #22; //Field const__0:Lclojure/lang/Var;
   3:   invokevirtual   #37; //Method clojure/lang/Var.get:()Ljava/lang/
Object;
   6:   checkcast       #39; //class clojure/lang/IFn
   9:   aload_1
   10:  invokeinterface #41,  2; //InterfaceMethod clojure/lang/IFn.invoke:
(Ljava/lang/Object;)Ljava/lang/Object;
   15:  dup
   16:  ifnull  44
   19:  getstatic       #47; //Field java/lang/Boolean.FALSE:Ljava/lang/
Boolean;
   22:  if_acmpeq       45
   25:  getstatic       #22; //Field const__0:Lclojure/lang/Var;
   28:  invokevirtual   #37; //Method clojure/lang/Var.get:()Ljava/lang/
Object;
   31:  checkcast       #39; //class clojure/lang/IFn
   34:  aload_1
   35:  invokeinterface #41,  2; //InterfaceMethod clojure/lang/IFn.invoke:
(Ljava/lang/Object;)Ljava/lang/Object;
   40:  astore_1
   41:  goto    0
   44:  pop
   45:  getstatic       #26; //Field const__1:Lclojure/lang/Var;
   48:  invokevirtual   #37; //Method clojure/lang/Var.get:()Ljava/lang/
Object;
   51:  checkcast       #39; //class clojure/lang/IFn
   54:  aload_1
   55:  aconst_null
   56:  astore_1
   57:  invokeinterface #41,  2; //InterfaceMethod clojure/lang/IFn.invoke:
(Ljava/lang/Object;)Ljava/lang/Object;
   62:  areturn

Our JIT reported incorrect stack size along the basic block introduced by 
the unneeded goto.
The bug was present in SVN rev 1205.

[CLJ-274] cannot close over mutable fields (in deftype)

Fri, 1 Oct 2010 09:35:00 -0500

Simplest case:

user=>
(deftype Bench [#^{:unsynchronized-mutable true} val]
Runnable
(run [_]
(fn [] (set! val 5))))

java.lang.IllegalArgumentException: Cannot assign to non-mutable: val (NO_SOURCE_FILE:5)

Functions should be able to mutate mutable fields in their surrounding deftype (just like inner classes do in Java).

Filed as bug, because the loop special form expands into a fn form sometimes:

user=>
(deftype Bench [#^{:unsynchronized-mutable true} val]
Runnable
(run [_]
(let [x (loop [] (set! val 5))])))
java.lang.IllegalArgumentException: Cannot assign to non-mutable: val (NO_SOURCE_FILE:9)