Re: Infinite loop in objc_storeWeak

[David Chisnall]

Can you try to produce a reduced test case?  I've tried a few things and I 
can't make it not work.  For example, this code:

int main(void)
{
    BBWeakRef *o = [BBWeakRef refWithTarget: [NSObject new]];
    NSLog(@"%@", o.target);
}

Logs (null) as expected.  A backtrace might help.  As would compiling libobjc2 
without optimisations (you can't actually be infinite looping in a loop that 
counts from 0 to 3, you must be looping in the outer loop for some reason).  
The most likely cause of this is that you're trying to create a weak reference 
to an object that's already been deallocated.  Perhaps you could try 
GSZombieEnabled=YES as well?

David

On 15 Jun 2012, at 14:38, Thomas Davie wrote:

> 
> On 15 Jun 2012, at 14:24, David Chisnall wrote:
> 
>> Hi Thomas,
>> 
>> A couple of questions:
>> 
>> Are you using the release version of libobjc or svn?  Your line numbers 
>> don't match up with mine, so it may be that this is a bug that's already 
>> fixed in svn.  I'm currently waiting for Quentin to test another bug fix and 
>> then I'll be doing a new release next week.
> 
> Hi David,
> I was at version 1.6, I have just pulled trunk, and tried again, I'm hitting 
> the same thing, but now reporting line 561 of arc.m.
> 
>> 
>> The second question is whether you remembered to initialise the weak pointer 
>> to 0, or call objc_initWeak() for the first store?
> 
> The weak pointer is an ivar, so it should be 0 initialised, yes.  Just for 
> completeness I've included my code below.
> 
> Thanks
> 
> Tom Davie
> 
> BBWeakRef.h
>> #import <Foundation/Foundation.h>
>> 
>> @interface BBWeakRef : NSObject
>> 
>> + (id)refWithTarget:(id)target;
>> - (id)initWithTarget:(id)target;
>> 
>> @property (weak) id target;
>> 
>> @end
> 
> BBWeakRef.m
>> #import "BBWeakRef.h"
>> 
>> @implementation BBWeakRef
>> 
>> @synthesize target = _target;
>> 
>> + (id)refWithTarget:(id)target
>> {
>>     return [[BBWeakRef alloc] initWithTarget:target];
>> }
>> 
>> - (id)initWithTarget:(id)target
>> {
>>     self = [super init];
>> 
>>     if (nil != self)
>>     {
>>         [self setTarget:target];
>>     }
>> 
>>     return self;
>> }
>> 
>> - (NSUInteger)hash
>> {
>>     return [[self target] hash];
>> }
>> 
>> - (BOOL)isEqual:(id)other
>> {
>>     if ([other isKindOfClass:[BBWeakRef class]])
>>     {
>>         return [[(BBWeakRef *)other target] isEqual:[self target]];
>>     }
>>     return NO;
>> }
>> 
>> @end
> 


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