API: Copy inputs in Index subclass constructors by default (GH#63388) #63398
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All checks are passing now. I've updated the PR to reflect the latest changes. |
mroeschke
requested changes
Dec 17, 2025
pandas/core/indexes/datetimes.py
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| if isinstance(data, (ExtensionArray, np.ndarray)): | ||
| # GH 63388 | ||
| if copy is not False: | ||
| if dtype is None or astype_is_view( | ||
| data.dtype, | ||
| pandas_dtype(dtype), | ||
| ): | ||
| data = data.copy() | ||
| copy = False |
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Can you create a @classmethod (place it in indexes/base.py near _raise_scalar_data_error), that encapsulates this logic and can be called here instead?
Extracts the copy/view validation logic into a shared classmethod on the base Index class, as requested during review.
Updates DatetimeIndex, TimedeltaIndex, PeriodIndex, and IntervalIndex to use the shared validation logic, reducing code duplication.
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AGENTS.md.Description:
This PR aligns the behavior of
DatetimeIndex,TimedeltaIndex,PeriodIndex, andIntervalIndexwith the baseIndexclass (andSeries) regarding thecopyparameter.Before, these constructors would ignore
copy=Noneand default to not copying the input data.Now,
copy=Nonedefaults toTruefornp.ndarrayandExtensionArrayinputs, ensuring that the resulting Index does not share memory with the mutable input array by default.Changes:
__new__signatures indatetimes.py,timedeltas.py,period.py, andinterval.pyto acceptcopy: bool | None.copyisNone(orTrue) and the input is an array/EA.Indexdocstring for thecopyparameter.dtypearguments (e.g."datetime64[ns]") are converted toDtypeObjbefore the view checks, preventingAttributeError.test_constructor_int64_nocopyandtest_array_tz) to explicitly passcopy=False. Since the default behavior changed tocopy=True, these tests required an update to continue verifying that the view based construction is still possible when requested.