Fix strpfromiso silently corrupting non-UTC timestamps - #562
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fit-alessandro-berti merged 1 commit intoJul 27, 2026
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…-intelligence-solutions#561) fix_naivety() used replace(tzinfo=timezone.utc) on already-aware datetimes, which relabels the timezone without converting the wall-clock value. A timestamp like 2026-07-23T10:00:00+05:00 (05:00 UTC) was silently stored as 2026-07-23T10:00:00+00:00, shifted by the source offset. Fix: only relabel (assume UTC) when the parsed value has no offset at all; convert via astimezone() when it does, matching the already-correct tz_convert("UTC") behavior in the sibling fix_dataframe_column() function. Adds regression tests covering positive/negative offsets, the existing Z-suffix path, naive input, and the aware-disabled branch. Signed-off-by: Praveen Mittal <pkmittal28@gmail.com>
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Dear @mittalpk thank you for your report. Could you start the contribution level agreement as in https://processintelligence.solutions/pm4py/contributing ? |
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Thanks @fit-alessandro-berti |
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Fixes #561
Summary
strpfromiso(the default ISO8601 date parser for Python >= 3.7) silently corrupts any timestamp that has a non-UTC offset, wheneverENABLE_DATETIME_COLUMNS_AWAREis enabled — which is the default for everyone except cuDF/RAPIDS installs.fix_naivety()calleddt.replace(tzinfo=timezone.utc)on an already-aware datetime.replace()only relabels the timezone; it does not convert the wall-clock value. A timestamp like2026-07-23T10:00:00+05:00(which is05:00 UTC) was silently stored as2026-07-23T10:00:00+00:00— shifted by 5 hours, with no warning or error.Fix
Only relabel (assume UTC) when the parsed value has no offset at all (nothing to convert from — same behavior as before for naive input). When it does have an offset, convert via
astimezone(timezone.utc), matching the already-correcttz_convert("UTC")behavior in the siblingfix_dataframe_column()function a few lines above it in the same file.Testing
Added
tests/dt_parsing_test.pycovering:Z-suffix path (still correct)ENABLE_DATETIME_COLUMNS_AWARE = Falsebranch (unchanged)Verified the two offset-conversion tests fail against the pre-fix code and pass against the fix. Also ran the existing
business_hours_test.pyandxes_impexp_test.py/xes_deep_coverage_test.pysuites (downstream consumers of this parser) — all pass, no regressions.How did I verify:
python -m pytest tests/dt_parsing_test.py tests/business_hours_test.py tests/xes_impexp_test.py tests/xes_deep_coverage_test.py -vfrom thetests/directory, all green.