FIX: DatetimeIndex.array should return DatetimeArray instead of ExtensionArray #1373
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…sionArray - Override array property in DatetimeIndex to return DatetimeArray - Add test case to verify the correct type is returned - Fixes issue where type checkers incorrectly identified return type
Dr-Irv
requested changes
Sep 17, 2025
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You need to make sure you set up the environment for testing. See https://github.com/pandas-dev/pandas-stubs/blob/main/docs/setup.md
I am pretty sure the pre-commit step will fail on this code.
You need to NOT use AI to do a contribution. The testing procedure that is documented is incorrect and doesn't follow the instructions in that link.
- establish the current poetry environment and run a complete test suite - Use the check (assrt_Type (...)) pattern required by project standards - Fix import order and code formatting through preset hook - All tests and type of chips now passionally pass
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Description
This PR fixes the type annotation issue where
DatetimeIndex.arrayandpd.to_datetime().arraywere incorrectly typed as returningExtensionArrayinstead of the specificDatetimeArray.Related Issue
Fixes #1371 -
to_datetime().array gives the generic ExtensionArray, but it turns out to be DatetimeArrayProblem
The current type stubs incorrectly specify that
DatetimeIndex.arrayreturns the genericExtensionArraytype, when in reality it returns the specificDatetimeArraytype at runtime. This caused type checkers (mypy and pyright) to incorrectly identify the return type.Solution
DatetimeArrayinpandas-stubs/core/indexes/datetimes.pyi@property def array(self) -> DatetimeArray: ...to theDatetimeIndexclasstest_datetime_index_array_property()intests/indexes/test_indexes.pyto verify the correct type is returnedChanges Made
pandas-stubs/core/indexes/datetimes.pyi- Added proper type annotationtests/indexes/test_indexes.py- Ensures the fix works correctlyVerification
DatetimeArrayas the return typeTesting
The fix has been verified with:
python -m pytest tests/indexes/test_indexes.py::test_datetime_index_array_property -v- Test passespd.to_datetime().arrayandpd.DatetimeIndex().arraywork correctly