[Twisted-Python] UncatchableExceptions

James Y Knight foom at fuhm.net
Sat Oct 30 00:31:00 EDT 2004

On Oct 30, 2004, at 12:06 AM, Bob Ippolito wrote:
> On Oct 29, 2004, at 17:52, Andrew Bennetts wrote:
>> <foom> exarkun: I suspect we should introduce a UncatchableExceptions
>>        constant somewhere
>> <foom> exarkun: and require that all except:'s are preceded by except
>>        UncatchableExceptions: raise
>> <exarkun> foom: It's possible that is a good idea.
>> <exarkun> foom: I'm not really sure, though.
>> <spiv> foom: With (KeyboardInterrupt, SystemExit, MemoryError, 
>> SystemError) ?
>> <foom> spiv: yes
>> I guess this would live in twisted.python somewhere, and the coding 
>> standard
>> would be updated to require its use instead of bare "except:"
>> Python-dev have discussed a similar measure for the python standard 
>> library
>> (in the exceptions module), but hadn't come to any consensus last 
>> time I
>> looked.
>> Thoughts?  Objections?
> Here is a link to the most recent discussion about this on python-dev:
> http://mail.python.org/pipermail/python-dev/2004-September/048609.html

I would like to point out that the method from the above-quoted IRC 
conversation is *NOT* what I'd like to see added in Python. I'd much 
prefer something like in the linked python-dev mail.

_However_, Twisted is supposed to work on 2.2, 2.3, and 2.4, none of 
which have the hypothetical new exception hierarchy that doesn't suck. 
Therefore, IMO, the best solution to fix things in Twisted, that will 
both work right now, and forwardly compatible, is to do as above and 
require that all except:'s (and except Exception's) are preceded by an 
except somemodule.UncatchableExceptions.


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