R: [Python-Dev] Deprecating string exceptions (original) (raw)

Skip Montanaro skip@pobox.com
Thu, 28 Mar 2002 10:30:26 -0600 

Guido> You're looking at this all wrong.  In the past, we've focused on
Guido> saying "unqualified except is wrong".  But IMO "except Exception"
Guido> or "except StandardError" is just as wrong!  You're still
Guido> catching way more exceptions than is good for you.

Point taken.

>> * I'm not saying you can't use "except:".  I'm not advocating a
>>   semantic change to the meaning of "except:".  (I am suggesting that
>>   KeyboardInterrupt should not inherit from StandardError.)  I'm
>>   saying that the recommended usage for application programmers
>>   should be to avoid it.

Guido> Sorry.  I told you I hadn't read the thread the first time around.

So, do we agree on this point?

Guido> We should fix the "except:" examples by catching a very specific
Guido> error, like AttributeError, TypeError or KeyError.  *Not* by
Guido> catching Exception or StandardError.

Correct. That's what the long-standing bug #411881 is about. It just deals with the standard library however, and doesn't delve into the stuff in Tools, Demos, etc.

Skip