Re: NSZombie

[Richard Frith-Macdonald]

On 26 Jun 2010, at 13:15, Sergey Golovin wrote:

> Hi!
> 
> Perhaps I passed some changes. I have a trouble  with the following program:
> 
> ------------------------------------------------------------------------------------------------------------------------
>   #import <Foundation/Foundation.h>
> 
>   int main(int argc, char **argv, char **env) {
>     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
>     NSObject *anObject = AUTORELEASE([NSObject new]);
> 
>     RELEASE(anObject);
>     RELEASE(anObject);
>     [pool release];
> 
>     return 0;
>   }
> ------------------------------------------------------------------------------------------------------------------------
> 
> I get the segmentation fault with NSZombieEnabled=NO as supposed.
> But I get nothing with NSZombieEnabled=YES. 
> 
> Is it a valid behavior?

It's wrong ... you should get an error message.

This appears to be a bug/feature of the objective-c runtime.
There is a category 'Object(NSObjectCompat)', which adds a dummy implementation 
for -release to the 'Object' class.
The 'NSZombie' class does NOT inherit from 'Object'.
Yet it appears that the implementation of 'release' from the category is being 
used.

A proper fix for this would probably be to cure the issue in the objc runtime.

A workaround is simply remove the category which defines -release for Object 
... this seems to work, and I make the change in subversion trunk.