Fix binary operations on attrs for Series and DataFrame

pandas/core/base.py

@@ -1480,9 +1480,9 @@ def _arith_method(self, other, op):
         with np.errstate(all="ignore"):
             result = ops.arithmetic_op(lvalues, rvalues, op)
 
-        return self._construct_result(result, name=res_name)
+        return self._construct_result(result, name=res_name, other=other)
 
-    def _construct_result(self, result, name):
+    def _construct_result(self, result, name, other=None):
         """
         Construct an appropriately-wrapped result from the ArrayLike result
         of an arithmetic-like operation.

pandas/core/frame.py

@@ -7879,7 +7879,7 @@ def _cmp_method(self, other, op):
 
         # See GH#4537 for discussion of scalar op behavior
         new_data = self._dispatch_frame_op(other, op, axis=axis)
-        return self._construct_result(new_data)
+        return self._construct_result(new_data, other=other)
 
     def _arith_method(self, other, op):
         if self._should_reindex_frame_op(other, op, 1, None, None):
@@ -7892,7 +7892,7 @@ def _arith_method(self, other, op):
 
         with np.errstate(all="ignore"):
             new_data = self._dispatch_frame_op(other, op, axis=axis)
-        return self._construct_result(new_data)
+        return self._construct_result(new_data, other=other)
 
     _logical_method = _arith_method
 
@@ -8088,8 +8088,7 @@ def _align_for_op(
 
         Parameters
         ----------
-        left : DataFrame
-        right : Any
+        other : Any
         axis : int
         flex : bool or None, default False
             Whether this is a flex op, in which case we reindex.
@@ -8101,6 +8100,7 @@ def _align_for_op(
         left : DataFrame
         right : Any
         """
+
         left, right = self, other
 
         def to_series(right):
@@ -8200,7 +8200,6 @@ def to_series(right):
                         "`left, right = left.align(right, axis=1)` "
                         "before operating."
                     )
-
             left, right = left.align(
                 right,
                 join="outer",
@@ -8209,6 +8208,9 @@ def to_series(right):
             )
             right = left._maybe_align_series_as_frame(right, axis)
 
+            # Ensure attributes are consistent between the aligned and original objects
+            if right.attrs != getattr(other, "attrs", {}):
+                right.attrs = getattr(other, "attrs", {}).copy()
         return left, right
 
     def _maybe_align_series_as_frame(self, series: Series, axis: AxisInt):
@@ -8269,9 +8271,9 @@ def _flex_arith_method(
 
                 new_data = self._dispatch_frame_op(other, op)
 
-        return self._construct_result(new_data)
+        return self._construct_result(new_data, other=other)
 
-    def _construct_result(self, result) -> DataFrame:
+    def _construct_result(self, result, other=None) -> DataFrame:
         """
         Wrap the result of an arithmetic, comparison, or logical operation.
 
@@ -8283,6 +8285,8 @@ def _construct_result(self, result) -> DataFrame:
         -------
         DataFrame
         """
+        if not getattr(self, "attrs", None) and getattr(other, "attrs", None):
+            self.__finalize__(other)
         out = self._constructor(result, copy=False).__finalize__(self)
         # Pin columns instead of passing to constructor for compat with
         #  non-unique columns case
@@ -8308,7 +8312,7 @@ def _flex_cmp_method(self, other, op, *, axis: Axis = "columns", level=None):
         self, other = self._align_for_op(other, axis, flex=True, level=level)
 
         new_data = self._dispatch_frame_op(other, op, axis=axis)
-        return self._construct_result(new_data)
+        return self._construct_result(new_data, other=other)
 
     @Appender(ops.make_flex_doc("eq", "dataframe"))
     def eq(self, other, axis: Axis = "columns", level=None) -> DataFrame:

pandas/core/indexes/base.py

@@ -7148,10 +7148,10 @@ def _logical_method(self, other, op):
         rvalues = extract_array(other, extract_numpy=True, extract_range=True)
 
         res_values = ops.logical_op(lvalues, rvalues, op)
-        return self._construct_result(res_values, name=res_name)
+        return self._construct_result(res_values, name=res_name, other=other)
 
     @final
-    def _construct_result(self, result, name):
+    def _construct_result(self, result, name, other=None):
         if isinstance(result, tuple):
             return (
                 Index(result[0], name=name, dtype=result[0].dtype),

pandas/core/series.py

@@ -5858,7 +5858,7 @@ def _cmp_method(self, other, op):
 
         res_values = ops.comparison_op(lvalues, rvalues, op)
 
-        return self._construct_result(res_values, name=res_name)
+        return self._construct_result(res_values, name=res_name, other=other)
 
     def _logical_method(self, other, op):
         res_name = ops.get_op_result_name(self, other)
@@ -5868,7 +5868,7 @@ def _logical_method(self, other, op):
         rvalues = extract_array(other, extract_numpy=True, extract_range=True)
 
         res_values = ops.logical_op(lvalues, rvalues, op)
-        return self._construct_result(res_values, name=res_name)
+        return self._construct_result(res_values, name=res_name, other=other)
 
     def _arith_method(self, other, op):
         self, other = self._align_for_op(other)
@@ -5930,11 +5930,15 @@ def _binop(self, other: Series, func, level=None, fill_value=None) -> Series:
             result = func(this_vals, other_vals)
 
         name = ops.get_op_result_name(self, other)
-        out = this._construct_result(result, name)
+
+        out = this._construct_result(result, name, other)
         return cast(Series, out)
 
     def _construct_result(
-        self, result: ArrayLike | tuple[ArrayLike, ArrayLike], name: Hashable
+        self,
+        result: ArrayLike | tuple[ArrayLike, ArrayLike],
+        name: Hashable,
+        other: AnyArrayLike | DataFrame | None = None,
     ) -> Series | tuple[Series, Series]:
         """
         Construct an appropriately-labelled Series from the result of an op.
@@ -5943,6 +5947,7 @@ def _construct_result(
         ----------
         result : ndarray or ExtensionArray
         name : Label
+        other : Series, DataFrame or array-like, default None
 
         Returns
         -------
@@ -5952,8 +5957,8 @@ def _construct_result(
         if isinstance(result, tuple):
             # produced by divmod or rdivmod
 
-            res1 = self._construct_result(result[0], name=name)
-            res2 = self._construct_result(result[1], name=name)
+            res1 = self._construct_result(result[0], name=name, other=other)
+            res2 = self._construct_result(result[1], name=name, other=other)
 
             # GH#33427 assertions to keep mypy happy
             assert isinstance(res1, Series)
@@ -5969,6 +5974,8 @@ def _construct_result(
         # Set the result's name after __finalize__ is called because __finalize__
         #  would set it back to self.name
         out.name = name
+        if not getattr(self, "attrs", None) and getattr(other, "attrs", None):
+            out.__finalize__(other)
         return out
 
     def _flex_method(self, other, op, *, level=None, fill_value=None, axis: Axis = 0):

pandas/tests/generic/test_finalize.py

@@ -427,53 +427,6 @@ def test_binops(request, args, annotate, all_binary_operators):
     if annotate == "right" and isinstance(right, int):
         pytest.skip("right is an int and doesn't support .attrs")
 
-    if not (isinstance(left, int) or isinstance(right, int)) and annotate != "both":
-        if not all_binary_operators.__name__.startswith("r"):
-            if annotate == "right" and isinstance(left, type(right)):
-                request.applymarker(
-                    pytest.mark.xfail(
-                        reason=f"{all_binary_operators} doesn't work when right has "
-                        f"attrs and both are {type(left)}"
-                    )
-                )
-            if not isinstance(left, type(right)):
-                if annotate == "left" and isinstance(left, pd.Series):
-                    request.applymarker(
-                        pytest.mark.xfail(
-                            reason=f"{all_binary_operators} doesn't work when the "
-                            "objects are different Series has attrs"
-                        )
-                    )
-                elif annotate == "right" and isinstance(right, pd.Series):
-                    request.applymarker(
-                        pytest.mark.xfail(
-                            reason=f"{all_binary_operators} doesn't work when the "
-                            "objects are different Series has attrs"
-                        )
-                    )
-        else:
-            if annotate == "left" and isinstance(left, type(right)):
-                request.applymarker(
-                    pytest.mark.xfail(
-                        reason=f"{all_binary_operators} doesn't work when left has "
-                        f"attrs and both are {type(left)}"
-                    )
-                )
-            if not isinstance(left, type(right)):
-                if annotate == "right" and isinstance(right, pd.Series):
-                    request.applymarker(
-                        pytest.mark.xfail(
-                            reason=f"{all_binary_operators} doesn't work when the "
-                            "objects are different Series has attrs"
-                        )
-                    )
-                elif annotate == "left" and isinstance(left, pd.Series):
-                    request.applymarker(
-                        pytest.mark.xfail(
-                            reason=f"{all_binary_operators} doesn't work when the "
-                            "objects are different Series has attrs"
-                        )
-                    )
     if annotate in {"left", "both"} and not isinstance(left, int):
         left.attrs = {"a": 1}
     if annotate in {"right", "both"} and not isinstance(right, int):
@@ -497,6 +450,18 @@ def test_binops(request, args, annotate, all_binary_operators):
     assert result.attrs == {"a": 1}
 
 
+@pytest.mark.parametrize("left", [pd.Series, pd.DataFrame])
+@pytest.mark.parametrize("right", [pd.Series, pd.DataFrame])
+def test_attrs_binary_operations(all_binary_operators, left, right):
+    # GH 51607
+    attrs = {"a": 1}
+    left = left([1])
+    left.attrs = attrs
+    right = right([2])
+    assert all_binary_operators(left, right).attrs == attrs
+    assert all_binary_operators(right, left).attrs == attrs
+
+
 # ----------------------------------------------------------------------------
 # Accessors