[Python-modules-team] Bug#1001289: colorclass: needs update for python3.10: 'Mapping' from 'collections' is removed

[Paul Gevers]

Source: colorclass
Version: 2.2.0-2.1
Severity: serious
X-Debbugs-CC: debian-ci at lists.debian.org
Tags: sid bookworm
User: debian-ci at lists.debian.org
Usertags: needs-update
Control: affects -1 src:python3-defaults

Dear maintainer(s),

With a recent upload of python3-defaults the autopkgtest of colorclass 
fails in testing when that autopkgtest is run with the binary packages 
of python3-defaults from unstable. It passes when run with only packages 
from testing. In tabular form:

                        pass            fail
python3-defaults       from testing    3.9.8-1
colorclass             from testing    2.2.0-2.1
all others             from testing    from testing

I copied some of the output at the bottom of this report. 
https://docs.python.org/3.9/library/collections.html says:
"""
Deprecated since version 3.3, will be removed in version 3.10: Moved 
Collections Abstract Base Classes to the collections.abc module. For 
backwards compatibility, they continue to be visible in this module 
through Python 3.9.
"""
Time to move on.

Currently this regression is blocking the migration of python3-defaults 
to testing [1]. Of course, python3-defaults shouldn't just break your 
autopkgtest (or even worse, your package), but it seems to me that the 
change in python3-defaults was intended and your package needs to update 
to the new situation.

If this is a real problem in your package (and not only in your 
autopkgtest), the right binary package(s) from python3-defaults should 
really add a versioned Breaks on the unfixed version of (one of your) 
package(s). Note: the Breaks is nice even if the issue is only in the 
autopkgtest as it helps the migration software to figure out the right 
versions to combine in the tests.

More information about this bug and the reason for filing it can be found on
https://wiki.debian.org/ContinuousIntegration/RegressionEmailInformation

Paul

[1] https://qa.debian.org/excuses.php?package=python3-defaults

https://ci.debian.net/data/autopkgtest/testing/amd64/c/colorclass/17344288/log.gz

Testing with python3.10:
Traceback (most recent call last):
   File "<string>", line 1, in <module>
   File "/usr/lib/python3/dist-packages/colorclass/__init__.py", line 
11, in <module>
     from colorclass.codes import list_tags  # noqa
   File "/usr/lib/python3/dist-packages/colorclass/codes.py", line 4, in 
<module>
     from collections import Mapping
ImportError: cannot import name 'Mapping' from 'collections' 
(/usr/lib/python3.10/collections/__init__.py)
autopkgtest [20:13:20]: test autodep8-python3

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