gh-123681: Check NORMALIZE_CENTURY behavior at runtime; require C99#136022
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…at the compile time It is needed to support cross-compiling. Remove macros Py_NORMALIZE_CENTURY and Py_STRFTIME_C99_SUPPORT.
encukou requested review from abalkin, corona10, ericsnowcurrently, erlend-aasland and pganssle as code owners
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If remove the C99 check in the C code, we should also remove _can_support_c99() in Lib/_pydatetime.py.
Look in #122272 for reasons for adding this check at first place.
| self.check_strftime_y2k('Y') | ||
| self.check_strftime_y2k('G') | ||
| deftest_strftime_y2k_c99(self): |
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Should not it be decorated with cpython_only?
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Good point! The meaning of cpython_only is not very clear.
This test might be usable for other implementations as well, so I think it's best for other implementations to skip the test if it doesn't work for them. IMO, cpython_only is best for things like bytecode details or sys.getsizeof.
But, that's just my opinion of course.
Lii43 approved these changes Jun 30, 2025
encukou added the 🔨 test-with-buildbots 
bedevere-bot commented Jul 9, 2025
🤖 New build scheduled with the buildbot fleet by @encukou for commit a52be23 🤖 Results will be shown at: https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F136022%2Fmerge If you want to schedule another build, you need to add the 🔨 test-with-buildbots label again. |
bedevere-bot removed the 🔨 test-with-buildbots 
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encukou commented Jul 10, 2025
The buildbot failures are unrelated. |
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encukou commented Aug 18, 2025
@serhiy-storchaka, are you OK with merging this? If you think #128444 is preferable then I'll defer to you. |
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serhiy-storchaka commented Aug 18, 2025
I think #128444 is preferable for backporting. In 3.15 we can remove checks for the C99 features. We will have a lot of time to test this and restore workarounds if this does not work on some obscure platforms. |
serhiy-storchaka approved these changes Aug 18, 2025
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On other hand, support for non-c99 strftime was removed in 3.14 a while ago, and there were no complains during beta testing. So, this LGTM if you plan to backport it to 3.14. We should fix 3.14 in one way or another.
encukou commented Aug 19, 2025
Misc/NEWS.d/next/Build/2025-01-03-13-02-06.gh-issue-123681.gQ67nK.rst Outdated Show resolvedHide resolved
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encukou merged commit 719e5c3 into python:main 44 checks passed
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Thanks @encukou for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14. |
miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Aug 19, 2025
… C99 (pythonGH-136022) A runtime check is needed to support cross-compiling. Remove the _Py_NORMALIZE_CENTURY macro. Remove _pydatetime.py's _can_support_c99. (cherry picked from commit 719e5c3) Co-authored-by: Petr Viktorin <[email protected]> Co-authored-by: Serhiy Storchaka <[email protected]>
GH-137947 is a backport of this pull request to the 3.14 branch. |
bedevere-bot commented Aug 19, 2025
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encukou added a commit that referenced this pull request Oct 7, 2025
…e C99 (GH-136022) (GH-137947) A runtime check is needed to support cross-compiling. Remove the _Py_NORMALIZE_CENTURY macro. Remove _pydatetime.py's _can_support_c99. (cherry picked from commit 719e5c3) Co-authored-by: Petr Viktorin <[email protected]> Co-authored-by: Serhiy Storchaka <[email protected]>
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This is a continuation of #128444.
CPython requires C11, so all C99 features should work.
We might need workaround if a supported platform misbehaves (hence this PR -- I want to feed the buildbots). But, IMO, any workarounds for unsupported platforms best left to the respective forks.
Serhiy's runtime check for
normalize_centuryis left in; I don't know about the details there.test_strftime_y2kfails on embedded Linux #123681