Public bug reported:
Python 3.4 released with a backward incompatible change in the logging module.
This bug has been tracked and fixed
upstream in http://bugs.python.org/issue22386. Summary is that
logging.getLevelName(lvl)
would return an integer value for a string lvl and a string value for an
integer lvl.
It mapped the two representations of log levels to each other. This behavior
existed
in python2.6 through python3.3 but was removed in 3.4. The new behavior in 3.4
was to
only map integer lvl values to strings.
[Impact]
Any python code that aims to be compatible with python2.6 and python3.4 must
carry its
own log level mappings (which may change under it because the loglevels are
extensible)
or access private data within the python logging module. Both approaches are
fragile
but thankfully upstream python 3.4 has patched this behavior so a downstream
update
to Trusty python3.4 would allow code to easily support 2.6 and 3.4.
[Test Case]
As detailed in the upstream bug you can test this easily via the
interactive interpreter.
Desired Behavior:
>>> logging.getLevelName('INFO')
20
>>> logging.getLevelName(20)
'INFO'
>>>
Current Trusty Behavior:
# This function call should return 20.
>>> logging.getLevelName('INFO')
'Level INFO'
>>> logging.getLevelName(20)
'INFO'
>>> logging.getLevelName(logging.INFO)
'INFO'
>>>
[Regression Potential]
The upstream patch is tiny and comes with a test case to track the desired
behavior
(upstream already had tests for the other behavior of this function). Beacuse
this
patch is so small and comes with new tests I think the regression potential is
very
small. Probably the only thing to consider is that new python3.4 code may have
come
to rely on this new backward incompatible behavior. But that would only be the
case
if code specifically looked for the mapping of 'Level %s' % 'stringlevelhere'.
** Affects: python
Importance: Unknown
Status: Unknown
** Affects: python3.4 (Ubuntu)
Importance: Undecided
Status: New
** Bug watch added: Python Roundup #22386
http://bugs.python.org/issue22386
** Also affects: python via
http://bugs.python.org/issue22386
Importance: Unknown
Status: Unknown
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https://bugs.launchpad.net/bugs/1382607
Title:
Backport python3.4 logging module backward incompatibility fix.
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