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:
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).
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.
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 :-(
