GeezerVison

Bug

time.strptime("2016 52 0", "%Y %W %w") resolves to 2017-01-01 but currently returns tm_yday=367. This is outside the documented 1–366 range; on Windows, passing the result to time.strftime() raises ValueError. A rollover from %U or %j can also leave a valid-looking but incorrect tm_yday.

_strptime converts the ordinal to a date and updates its year, month, and day, but leaves julian relative to the input year. Recompute julian from the resolved date when the year changes.

Tests

• Added regression cases for %W, %U, and %j crossing into the next year. These failed before the fix and pass afterward.
• PCbuild\amd64\python.exe -X dev -m test test_strptime test_time test_datetime: 1,292 tests run, 123 skipped; success.
• PCbuild\amd64\python.exe Tools\patchcheck\patchcheck.py: success.
• Full local Windows suite (-X dev -m test -j4): 50,966 tests run; 443 test files passed, 3 unrelated files failed. test_os.test_device_encoding fails because this runner presents stdin as a TTY but os.device_encoding(0) is None (the module passes with piped stdin). test_posixpath.test_realpath_invalid_paths expects FileNotFoundError for a NUL path but gets ValueError (reproduces in isolation). test_ssl.test_pha_required_nocert saw a localized Windows connection-reset message that did not match its English regex (the module passes in isolation).

Fixes #73267.

AI assistance was used to investigate and prepare this change. The patch and test results were reviewed before submission.