[Python-Dev] Revert #12085 fix for del attribute error message (original) (raw)

Terry Reedy tjreedy at udel.edu
Sun Sep 22 01:55:05 CEST 2013

On 9/21/2013 6:15 PM, R. David Murray wrote:

On Sat, 21 Sep 2013 17:16:41 -0400, Terry Reedy <tjreedy at udel.edu> wrote:

When an AttributeError is raised in a del method, it is caught and ignored, except that it is not completely ignored but is replaced by a warning message sent to stderr. Example: >>> class C(): def del(self): raise AttributeError

>>> c=C() >>> del c Exception AttributeError: AttributeError() in <bound method C._del_ of_ _<_main_.C object at 0x000000000351A198>> ignored This is a replacement for a traceback. In later Python versions, the full traceback is printed.

The above is 3.3.2. In 3.4.0a2, the traceback of the ignored exception is indeed printed.

Exception ignored in: <bound method C.__del__ of <__main__.C object at 0x00000000039946D8>> Traceback (most recent call last): File "<pyshell#0>", line 2, in del AttributeError:

In the general case it represents a bug in the code that should be fixed. Most such errors arise from the vagaries of module finalization (such as your issue 19021),

Lets call that a buglet ;-). Not really harmful, but annoying. Accepting that even such buglets 'should' be fixed in the stdllib, so that the message does not appear, is there any reason not to make it a RuntimeWarning so that users who care about clean output can filter it out while waiting for us to fix it?

This would be a separate issue from #12085.

but not all of them do: the rest represent real bugs in del methods (which are executed asynchronously in the general case).

Which is why the message should be printed, so the developer can decide.

-- Terry Jan Reedy

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