[Python-Dev] Backwards Incompatibility in logging module in 3.4?

[Don Spaulding]

On Thu, Jun 12, 2014 at 6:45 PM, Victor Stinner <victor.stinner at gmail.com>
wrote:

> Hi,
>
> 2014-06-13 0:38 GMT+02:00 Don Spaulding <donspauldingii at gmail.com>:
> > Is this a bug or an intentional break?  If it's the latter, shouldn't
> this
> > at least be mentioned in the "What's new in Python 3.4" document?
>
> IMO the change is intentional. The previous behaviour was not really
> expected.
>

I agree that the change seems intentional.  However, as Nick mentioned, the
ticket doesn't really discuss the repercussions of changing the output of
the function.  As far as I can tell, this function has returned an int when
given a string since it was introduced in Python 2.3.  I think it's
reasonable to call a function's behavior "expected" after 11 years in the
wild.


>
> Python 3.3 documentation is explicit: the result is a string and the
> input paramter is an integer. logging.getLevelName("DEBUG") was more
> an implementation
>
> https://docs.python.org/3.3/library/logging.html#logging.getLevelName
> "Returns the textual representation of logging level lvl. If the level
> is one of the predefined levels CRITICAL, ERROR, WARNING, INFO or
> DEBUG then you get the corresponding string. If you have associated
> levels with names using addLevelName() then the name you have
> associated with lvl is returned. If a numeric value corresponding to
> one of the defined levels is passed in, the corresponding string
> representation is returned. Otherwise, the string ‘Level %s’ % lvl is
> returned."
>
> If your code uses something like
> logger.setLevel(logging.getLevelName("DEBUG")), use directly
> logger.setLevel("DEBUG").
>
> This issue was fixed in OpenStack with this change:
> https://review.openstack.org/#/c/94028/6/openstack/common/log.py,cm
> https://review.openstack.org/#/c/94028/6
>
> Victor
>

I appreciate the pointer to the OpenStack fix.  I've actually already
worked around the issue in my project (although without much elegance, I'll
readily admit).

I opened up an issue on the tracker for this:
http://bugs.python.org/issue21752

I apologize if that was out of turn.
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