[Python-Dev] Proposing a sys.special_exceptions tuple (original) (raw)

Nick Coghlan ncoghlan at email.com
Fri Oct 1 08:51:07 CEST 2004

Quoting Raymond Hettinger <python at rcn.com>:

Since we're trying to catch anything not special, is the intended usage something like this:

try: func() except specialexceptions: raise except: altfunc() # handle non-special exceptions

Yep. It's essentially a workaround for the fact that we can't do anything too drastic to the exception heirarchy without serious backwards compatibility problems, but have some 'critical' exceptions that most code shouldn't be suppressing.

At the moment, 'except:' is bad, and in most cases 'except Exception:' isn't any better (which surprised me - I didn't realise this until Tim brought it up recently). Tim suggested 'except StandardError:' which is an improvement but still not quite right (SystemExit and StopIteration make it through then, but MemoryError and KeyboardInterrupt still get eaten).

I'm dreaming of the day when I can hit 'Ctrl-C' on any Python script and actually have the darn thing stop without hitting it 10 more times ;)

Cheers, Nick.

-- Nick Coghlan Brisbane, Australia

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