[Zope3-dev] Re: [Zope-dev] Re: tal:on-error is a bare except...

[Tres Seaver]

Jim Fulton wrote:
> Tres Seaver wrote:
> 
>> Jim Fulton wrote:
>>
> 
> ...
> 
>>> Hm. I wonder if SystemError would be appropriate here.
>>> (Zope may abuse SystemError, but we could fix that.)
>>
>>
>>
>> RuntimeError exists, but has the wrong bases (StandardError, which 
>> derives from Exception).  SystemError has StandardError as its base, too.
> 
> 
> I'm not trying to solve the problem of making an exception uncatchable.
> If we said that RuntimeError or SystemError (or whatever) shouldn't
> be caught by a bare excpt, then we could, with present Python
> say that the following is the correct idiom for a bare except:
> 
>   try:
>       ...
>   except:
>       if isinstance(sys.exc_info()[1], RuntimeError):
>           raise
>       ... do what we do for ctachable errors

OK.  I think the spelling would be better as follows:

   try:
       ...
   except RuntimeError:  # I'm not smart enough to catch these
       raise
   except:
       ....

That is how most of the "sprinkled" ConflictError checks look in Zope2 
code, anyway.


Tres.
-- 
===============================================================
Tres Seaver                                tseaver at zope.com
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