EXC_BAD_ACCESS is _class_getName when throwing NSException with ARC enabled

text

Throwing an exception like this:

  @throw [NSException exceptionWithName:@"Exception" reason:@"none" userInfo:nil];

in a method, and trying to catch it in a method up the stack, causes a EXC_BAD_ACCESS in:

#0	0x36221fd0 in _class_getName ()
#1	0x36221fbc in object_getClassName ()
#2	0x362261fe in objc_exception_throw ()

But only on an iOS device.
The exact same code works as expected without a crash on the simulator.

Workarounds:
* Use CFBridgingRetain() on the exception (shown in the example project)
* or store the exception to a local variable first and then throw it

Filed as rdar://10330762

@tylercollier: what version of Xcode are you using, and on which version of iOS are you running on the device?

Xcode 4.2.1 build 4D502, iOS 5.0.1 (9A405). I found your post because I was having the same problem with my own app, but your app doesn't produce the same observations. I'm not sure what the difference is.

@tylercollier: It seems the specific bug I have reported to Apple and which the demo exposes was fixed, as it doesn't crash any more for me. It did definitely crash at the time of reporting, I confirmed that with various Xcode/iOS combos back then.

So it seems you're seeing a different, but maybe similar issue?

@kommen, might I have a fixed version of Xcode/iOS now too? My issue was exactly the same as yours. Using [NSException exceptionWithName] would cause EXC_BAD_ACCESS on a device but not the simulator. Using your project, which I modified slightly to run on an iPhone instead of an iPad because I have the former and not the latter, I don't see that issue. And I just reran my project and the EXC_BAD_ACCESS did not happen.

@tylercollier: Yeah, so it looks like Apple fixed that then.