REF: Use _maybe_copy_input in Index subclasses (GH#63388)

Updates DatetimeIndex, TimedeltaIndex, PeriodIndex, and IntervalIndex to use the shared validation logic, reducing code duplication.

Author: zacharym-collins

pandas/core/indexes/datetimes.py

@@ -37,10 +37,8 @@
 )
 from pandas.util._exceptions import find_stack_level
 
-from pandas.core.dtypes.astype import astype_is_view
 from pandas.core.dtypes.common import (
     is_scalar,
-    pandas_dtype,
 )
 from pandas.core.dtypes.dtypes import (
     ArrowDtype,
@@ -49,7 +47,6 @@
 from pandas.core.dtypes.generic import ABCSeries
 from pandas.core.dtypes.missing import is_valid_na_for_dtype
 
-from pandas.core.arrays import ExtensionArray
 from pandas.core.arrays.datetimes import (
     DatetimeArray,
     tz_to_dtype,
@@ -689,15 +686,8 @@ def __new__(
 
         name = maybe_extract_name(name, data, cls)
 
-        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
+        # GH#63388
+        data, copy = cls._maybe_copy_input(data, copy, dtype)
 
         if (
             isinstance(data, DatetimeArray)

pandas/core/indexes/interval.py

@@ -35,7 +35,6 @@
 )
 from pandas.util._exceptions import rewrite_exception
 
-from pandas.core.dtypes.astype import astype_is_view
 from pandas.core.dtypes.cast import (
     find_common_type,
     infer_dtype_from_scalar,
@@ -62,7 +61,6 @@
 from pandas.core.dtypes.missing import is_valid_na_for_dtype
 
 from pandas.core.algorithms import unique
-from pandas.core.arrays import ExtensionArray
 from pandas.core.arrays.datetimelike import validate_periods
 from pandas.core.arrays.interval import (
     IntervalArray,
@@ -265,15 +263,8 @@ def __new__(
     ) -> Self:
         name = maybe_extract_name(name, data, cls)
 
-        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
+        # GH#63388
+        data, copy = cls._maybe_copy_input(data, copy, dtype)
 
         with rewrite_exception("IntervalArray", cls.__name__):
             array = IntervalArray(

pandas/core/indexes/period.py

@@ -27,16 +27,13 @@
     set_module,
 )
 
-from pandas.core.dtypes.astype import astype_is_view
 from pandas.core.dtypes.common import (
     is_integer,
-    pandas_dtype,
 )
 from pandas.core.dtypes.dtypes import PeriodDtype
 from pandas.core.dtypes.generic import ABCSeries
 from pandas.core.dtypes.missing import is_valid_na_for_dtype
 
-from pandas.core.arrays import ExtensionArray
 from pandas.core.arrays.period import (
     PeriodArray,
     period_array,
@@ -241,15 +238,8 @@ def __new__(
 
         freq = validate_dtype_freq(dtype, freq)
 
-        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
+        # GH#63388
+        data, copy = cls._maybe_copy_input(data, copy, dtype)
 
         # PeriodIndex allow PeriodIndex(period_index, freq=different)
         # Let's not encourage that kind of behavior in PeriodArray.

pandas/core/indexes/timedeltas.py

@@ -7,8 +7,6 @@
     cast,
 )
 
-import numpy as np
-
 from pandas._libs import (
     index as libindex,
     lib,
@@ -21,15 +19,13 @@
 from pandas._libs.tslibs.dtypes import abbrev_to_npy_unit
 from pandas.util._decorators import set_module
 
-from pandas.core.dtypes.astype import astype_is_view
 from pandas.core.dtypes.common import (
     is_scalar,
     pandas_dtype,
 )
 from pandas.core.dtypes.dtypes import ArrowDtype
 from pandas.core.dtypes.generic import ABCSeries
 
-from pandas.core.arrays import ExtensionArray
 from pandas.core.arrays.timedeltas import TimedeltaArray
 import pandas.core.common as com
 from pandas.core.indexes.base import (
@@ -172,15 +168,8 @@ def __new__(
     ):
         name = maybe_extract_name(name, data, cls)
 
-        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
+        # GH#63388
+        data, copy = cls._maybe_copy_input(data, copy, dtype)
 
         if is_scalar(data):
             cls._raise_scalar_data_error(data)