My code was crashing, with output on the console:
*** Assertion failure in -[NSTextFieldCell _objectValue:forString:], AppKit.subproj/NSCell.m:1131 An uncaught exception was raised Invalid parameter not satisfying: aString != nil
So I set a breakpoint at - [NSException raise]. I hit the breakpoint, but the next call on the stack was runModalForWindow — there was no indication of what code of mine was doing the mischief. I tried -[NSCell setStringValue:], but hit lots of cases where nothing was wrong. Finally, after some googling, I tried breaking on:
-[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:]
Which was perfect. The call stack showed exactly where I was setting the text field string value to nil, which in turn uncovered a bug in my network error checking.
Posted by Jim Matthews 