Bug report

Bug description:

The PGO test suite fails on the test_datetime tests; in particular, the test_strftime_y2k test cases. It looks like the padding is wrong:

cpython-3.14> AssertionError: '1-01-01' != '0001-01-01'

I believe this is related to:

• test_strftime_y2k fails on embedded Linux #123681 (superseded by this issue)
• datetime.strftime("%Y") is not padding correctly #120713
• gh-123681: handle c99-specific specifiers for strftime when cross-compiling #123861

Note this is occuring in the python-build-standalone builds. I have not reproduced it independently. This isn't a problem during our x86_64_v4 builds because we're not running PGO on them. The normal x86_64 build is working.

cpython-3.14> test_system_transitions (test.datetimetester.ZoneInfoTest_Fast.test_system_transitions) ... ok
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=1, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '1-01-01' != '0001-01-01'
cpython-3.14> - 1-01-01
cpython-3.14> + 0001-01-01
cpython-3.14> ? +++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=1, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=48, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '48-01-01' != '0048-01-01'
cpython-3.14> - 48-01-01
cpython-3.14> + 0048-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=48, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=70, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '70-01-01' != '0070-01-01'
cpython-3.14> - 70-01-01
cpython-3.14> + 0070-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=70, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=999, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '999-01-01' != '0999-01-01'
cpython-3.14> - 999-01-01
cpython-3.14> + 0999-01-01
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDate_Fast.test_strftime_y2k) (year=999, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '9' != '09'
cpython-3.14> - 9
cpython-3.14> + 09
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=1, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '1-01-01' != '0001-01-01'
cpython-3.14> - 1-01-01
cpython-3.14> + 0001-01-01
cpython-3.14> ? +++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=1, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=48, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '48-01-01' != '0048-01-01'
cpython-3.14> - 48-01-01
cpython-3.14> + 0048-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=48, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=70, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '70-01-01' != '0070-01-01'
cpython-3.14> - 70-01-01
cpython-3.14> + 0070-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=70, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=999, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '999-01-01' != '0999-01-01'
cpython-3.14> - 999-01-01
cpython-3.14> + 0999-01-01
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTime_Fast.test_strftime_y2k) (year=999, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '9' != '09'
cpython-3.14> - 9
cpython-3.14> + 09
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=1, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '1-01-01' != '0001-01-01'
cpython-3.14> - 1-01-01
cpython-3.14> + 0001-01-01
cpython-3.14> ? +++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=1, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=48, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '48-01-01' != '0048-01-01'
cpython-3.14> - 48-01-01
cpython-3.14> + 0048-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=48, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=70, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '70-01-01' != '0070-01-01'
cpython-3.14> - 70-01-01
cpython-3.14> + 0070-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=70, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=999, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '999-01-01' != '0999-01-01'
cpython-3.14> - 999-01-01
cpython-3.14> + 0999-01-01
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestDateTimeTZ_Fast.test_strftime_y2k) (year=999, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '9' != '09'
cpython-3.14> - 9
cpython-3.14> + 09
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=1, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '1-01-01' != '0001-01-01'
cpython-3.14> - 1-01-01
cpython-3.14> + 0001-01-01
cpython-3.14> ? +++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=1, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=48, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '48-01-01' != '0048-01-01'
cpython-3.14> - 48-01-01
cpython-3.14> + 0048-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=48, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=70, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '70-01-01' != '0070-01-01'
cpython-3.14> - 70-01-01
cpython-3.14> + 0070-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=70, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=99, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '99-01-01' != '0099-01-01'
cpython-3.14> - 99-01-01
cpython-3.14> + 0099-01-01
cpython-3.14> ? ++
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=99, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '0' != '00'
cpython-3.14> - 0
cpython-3.14> + 00
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTi
cpython-3.14> me_Fast.test_strftime_y2k) (year=999, specifier='F')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '999-01-01' != '0999-01-01'
cpython-3.14> - 999-01-01
cpython-3.14> + 0999-01-01
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ======================================================================
cpython-3.14> FAIL: test_strftime_y2k (test.datetimetester.TestSubclassDateTime_Fast.test_strftime_y2k) (year=999, specifier='C')
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Traceback (most recent call last):
cpython-3.14>   File "/build/Python-3.14.0a3/Lib/test/datetimetester.py", line 1814, in test_strftime_y2k
cpython-3.14>     self.assertEqual(d.strftime(f"%{specifier}"), expected)
cpython-3.14>     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cpython-3.14> AssertionError: '9' != '09'
cpython-3.14> - 9
cpython-3.14> + 09
cpython-3.14> ? +
cpython-3.14>
cpython-3.14>
cpython-3.14> ----------------------------------------------------------------------
cpython-3.14> Ran 1058 tests in 3.495s
cpython-3.14>
cpython-3.14> FAILED (failures=48, skipped=52)
cpython-3.14> test test_datetime failed

You can see the run in CI here, though it does not include the test output because you have to hack the test suite to show verbose output with --pgo.

I believe this is basically a duplicate of #123681, but I figured I'd open a issue for discoverability.

CPython versions tested on:

3.14

Operating systems tested on:

Linux

Linked PRs

• gh-128104: Remove Py_STRFTIME_C99_SUPPORT; require C99-compliant strftime #128106