Open Radar

 
Summary:
========

Using NSOperationQueue results in a memory leak.

Steps to Reproduce:
===================

The following code reproduces the problem. The flow is as follows:
1) Queue up a batch of 1000 trivial NSOperations
2) Wait for the queue to empty
3) Sleep for a second to ensure there is no CPU load
4) Force a collection4
5) Rinse and repeat

Compile the following code with:
gcc -x objective-c main.m -o test -fobjc-gc-only -framework Cocoa -g

#import <Cocoa/Cocoa.h>
#include <libkern/OSAtomic.h>

volatile int64_t globalCounter;

@interface Operation : NSOperation
+ (Operation*) operation;
@end

@implementation Operation
+ (Operation*) operation
{
        return [[[Operation alloc] init] autorelease];
}

- (void) main
{
        OSAtomicIncrement64(&globalCounter);
}
@end

int main(int argc, char **argv)
{
        NSOperationQueue *queue = [[NSOperationQueue alloc] init];
        int64_t counter = 0;

        [queue setMaxConcurrentOperationCount:4];

        while (1) {
                [queue addOperation:[Operation operation]];
                counter++;

                if (counter % 1000 == 0) {
                        while ([[queue operations] count]) {
                                usleep(100);
                        }

                        usleep(1000 * 1000);
                        [[NSGarbageCollector defaultCollector] collectExhaustively];
                }
        }
}

Expected Results:
=================

No memory leak

Actual Results:
===============

Memory leak... a pretty quick one too!

Notes:
======
Please note, I have tried this on 10.5.7 and Snow Leopard 10A421, both platforms reproduce the problem. It is not reproducible with retain/release code.