[jkubicek]

Our app uses this method to cache images and we were seeing huge memory leaks due to this bug. Like the example showed, the bug manifested itself in a retain count being incremented on property access. Our solution was something like this:

    if ([self.data retainCount] != [self.data retainCount]) {
      [[[self.data release] release] release];
    }

Written from memory, so excuse any mistakes. First (and only) time I've ever seen a legitimate use for `retainCount`. @bbum would be proud (or perhaps horrified).

[bennyg]

So in the first line, it has 1 and then checking to see if it's equal bumps it to 2 allocs, and finally the third call, to begin releasing, brings it to 3 (then removal of all 3)?

That's super weird - I have yet to encounter something along these lines in my Cocoa work so far. Solid idea to beat the system there. I just hope it's got a nice comment above it haha.

[asarazan]

Yeah this is the general idea we went with. We did our best to synchronize around it, but unfortunately we can never have total control, which necessarily introduces race conditions.

I would imagine this is what leads to the 0.4% crash rate I mentioned at the top of the article :-(