REF: de-duplicate _wrap_joined_index (#36282)

Author: jbrockmendel

pandas/core/indexes/base.py

@@ -3877,7 +3877,7 @@ def _join_monotonic(self, other, how="left", return_indexers=False):
 
     def _wrap_joined_index(self, joined, other):
         name = get_op_result_name(self, other)
-        return Index(joined, name=name)
+        return self._constructor(joined, name=name)
 
     # --------------------------------------------------------------------
     # Uncategorized Methods

pandas/core/indexes/category.py

@@ -767,7 +767,8 @@ def _wrap_joined_index(
         self, joined: np.ndarray, other: "CategoricalIndex"
     ) -> "CategoricalIndex":
         name = get_op_result_name(self, other)
-        return self._create_from_codes(joined, name=name)
+        cat = self._data._from_backing_data(joined)
+        return type(self)._simple_new(cat, name=name)
 
 
 CategoricalIndex._add_logical_methods_disabled()

pandas/core/indexes/datetimelike.py

@@ -603,7 +603,9 @@ def _wrap_joined_index(self, joined: np.ndarray, other):
         else:
             self = cast(DatetimeTimedeltaMixin, self)
             freq = self.freq if self._can_fast_union(other) else None
-        new_data = type(self._data)._simple_new(joined, dtype=self.dtype, freq=freq)
+
+        new_data = self._data._from_backing_data(joined)
+        new_data._freq = freq
 
         return type(self)._simple_new(new_data, name=name)
 

pandas/core/indexes/multi.py

@@ -3637,7 +3637,7 @@ def delete(self, loc):
 
     def _wrap_joined_index(self, joined, other):
         names = self.names if self.names == other.names else None
-        return MultiIndex.from_tuples(joined, names=names)
+        return self._constructor(joined, names=names)
 
     @doc(Index.isin)
     def isin(self, values, level=None):

pandas/core/indexes/numeric.py

@@ -33,7 +33,6 @@
 from pandas.core import algorithms
 import pandas.core.common as com
 from pandas.core.indexes.base import Index, maybe_extract_name
-from pandas.core.ops import get_op_result_name
 
 _num_index_shared_docs = dict()
 
@@ -262,10 +261,6 @@ class Int64Index(IntegerIndex):
     _engine_type = libindex.Int64Engine
     _default_dtype = np.dtype(np.int64)
 
-    def _wrap_joined_index(self, joined, other):
-        name = get_op_result_name(self, other)
-        return Int64Index(joined, name=name)
-
     @classmethod
     def _assert_safe_casting(cls, data, subarr):
         """
@@ -324,10 +319,6 @@ def _convert_index_indexer(self, keyarr):
 
     # ----------------------------------------------------------------
 
-    def _wrap_joined_index(self, joined, other):
-        name = get_op_result_name(self, other)
-        return UInt64Index(joined, name=name)
-
     @classmethod
     def _assert_safe_casting(cls, data, subarr):
         """