On 24. 06. 21 0:35, Barry Warsaw wrote:
Miro, what tests (outside of Python itself) do you think may break, and do you have a way to check that?
Any tests that import from asynchat, asyncore or smtpd (in the tests or in the tested code, even transitively trough other projects) if DeprecationWarnings are treated as errors by default -- many projects do this in tests (which is a very good way to get alerted of such deprecations when they happen) or even in setup.py (which I found rather weird). Some examples of such failures with different new DeprecationWarnings from the recent Python 3.10 pre-releases testing (mostly fixed now): - jinja2, subprocess-tee, sqlalchemy and more failed to build with Python 3.10: DeprecationWarning: There is no current event loop (treated as error) - colcon-ros, ruamel-yaml, flake8 and more failed to build with Python 3.10: DeprecationWarning: The distutils package deprecated and slated for removal in Python 3.12 (got it via setuptools usage, treated as error) - cherrypy failed to build with Python 3.10: pytest exited with no clear error message [1] Yes, we have a way to check all Fedora's Python packages by reusing our Python 3.10 pre-releases test-rebuild-everything mechanism, but it takes a few days to finish the builds and analyze the failures. Test failures caused by DeprecationWarnings are sometimes not obvious, e.g. not recognizable directly from the logs -- especially if they obscure some output that's checked for equality or line count (and all you get in the log is AssertionError: 20 != 21), or when they exit entire pytest session without any error message (arguably, that does not happen that often [1]). When such problems are found, it takes some time to report the problem to upstreams, fix the problem or workaround it (e.g. by filtering or ignoring the warning, which is not always trivial, especially when it propagates trough subprocess [2]). At this point of the release cycle, I'd rather recognize, triage and report regressions. [1] https://github.com/cherrypy/cherrypy/issues/1914#issuecomment-848780246 [2] https://github.com/pytest-dev/pytest/pull/8664
-Barry
On Wed, Jun 23, 2021, at 17:15, Miro Hrončok wrote:
On 23. 06. 21 23:49, Irit Katriel via Python-Dev wrote:
Barry and I are working on a patch to add deprecation warnings in 3.10 when
one
of these are imported [6]. Let us know if you have any comments on this plan.
With my Fedora Python maintainer hat on, I am not particularly happy about this.
DeprecationWarnings have a tendency to break tests. I assumed Python 3.10.0b1 to be the last release that intentionally breaks things that worked with Python 3.9.
It's not a strong opinion and if there is a consensus that adding new DeprecationWarnings is not considered "new feature" or "breaking change", I won't fight it, but it feels wrong.
-- Miro Hrončok -- Phone: +420777974800 IRC: mhroncok
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