title: What could cause my NSException to be swallowed up?
body: <p>I have some assertion code that raises an NSException on bad input.</p>
  
  <p>Today, I messed up one of my methods and generated a condition which triggered the exception.  However, unlike usual, XCode didn't stop on the exception raise.  It kept going.  It took me a LOT of NSLog calls to figure this out, because it also unwound the entire call stack so I couldn't figure out where it was dying.</p>
  
  <p>I have a custom unhandled exception function defined (AND breakpointed), and everything was working until today (when I have no idea what changed).</p>
  
  <p>What could cause XCode and/or the Objective-C runtime to swallow my NSExceptions whole and not tell me?</p>
  
  <p>Interestingly, the code kept running just fine - went back out to the main run loop.</p>
  
  <p>==EDIT==</p>
  
  <p>This just happened to me again, 5 days later, in a different place.  Beginning to suspect buggy behavior in Xcode 4 while debugging.  Watch this space.</p>