share _wrap_joined_index (pandas-dev#30599)

Author: jbrockmendel

pandas/core/indexes/datetimelike.py

@@ -35,6 +35,7 @@
 import pandas.core.indexes.base as ibase
 from pandas.core.indexes.base import Index, _index_shared_docs
 from pandas.core.indexes.numeric import Int64Index
+from pandas.core.ops import get_op_result_name
 from pandas.core.tools.timedeltas import to_timedelta
 
 from pandas.tseries.frequencies import DateOffset, to_offset
@@ -924,6 +925,22 @@ def _is_convertible_to_index_for_join(cls, other: Index) -> bool:
             return True
         return False
 
+    def _wrap_joined_index(self, joined, other):
+        name = get_op_result_name(self, other)
+        if (
+            isinstance(other, type(self))
+            and self.freq == other.freq
+            and self._can_fast_union(other)
+        ):
+            joined = self._shallow_copy(joined)
+            joined.name = name
+            return joined
+        else:
+            kwargs = {}
+            if hasattr(self, "tz"):
+                kwargs["tz"] = getattr(other, "tz", None)
+            return self._simple_new(joined, name, **kwargs)
+
 
 def wrap_arithmetic_op(self, other, result):
     if result is NotImplemented:

pandas/core/indexes/datetimes.py

@@ -632,20 +632,6 @@ def snap(self, freq="S"):
         # we know it conforms; skip check
         return DatetimeIndex._simple_new(snapped, name=self.name, tz=self.tz, freq=freq)
 
-    def _wrap_joined_index(self, joined, other):
-        name = get_op_result_name(self, other)
-        if (
-            isinstance(other, DatetimeIndex)
-            and self.freq == other.freq
-            and self._can_fast_union(other)
-        ):
-            joined = self._shallow_copy(joined)
-            joined.name = name
-            return joined
-        else:
-            tz = getattr(other, "tz", None)
-            return self._simple_new(joined, name, tz=tz)
-
     def _parsed_string_to_bounds(self, reso, parsed):
         """
         Calculate datetime bounds for parsed time string and its resolution.

pandas/core/indexes/timedeltas.py

@@ -31,7 +31,6 @@
     DatetimelikeDelegateMixin,
     DatetimeTimedeltaMixin,
 )
-from pandas.core.ops import get_op_result_name
 
 from pandas.tseries.frequencies import to_offset
 
@@ -283,18 +282,6 @@ def _union(self, other, sort):
                     result._set_freq("infer")
             return result
 
-    def _wrap_joined_index(self, joined, other):
-        name = get_op_result_name(self, other)
-        if (
-            isinstance(other, TimedeltaIndex)
-            and self.freq == other.freq
-            and self._can_fast_union(other)
-        ):
-            joined = self._shallow_copy(joined, name=name)
-            return joined
-        else:
-            return self._simple_new(joined, name)
-
     def _fast_union(self, other):
         if len(other) == 0:
             return self.view(type(self))