The other day I posted about how NSOperationQueue is broken and can't be used. At Rogue Amoeba we liked the API so much we decided to create a non-broken version, so we've released RAOperationQueue. It's not a 100% replacement, as it has some significant limitations (and some benefits) compared to NSOperationQueue, but we've found it to be very useful. For more information, click the link above.

I just hit a subtle but commonly known bug for the first time. I thought I'd share my fun with the world. Everybody reading this blog should know about autorelease pools and how they work in Cocoa. As everybody knows, every time you go through the event loop, Cocoa blows away the old pool and makes a new one for you, so that all of your autoreleased objects go away and your new ones go into a fresh pool. That way you never build up more objects than get produced during a single event loop cycle.

The most interesting bugs for me are the bugs which appear at the confluence of many different things. Module A has a small defect, which happens to expose a lack in module B, causing it to feed bad data to module C, which then behaves oddly. With a difference in any of those modules, the problem might never have appeared. I recently saw a non-bug which is a great example of this kind of interaction.