REGR: fix calling numpy bitwise ufunc with Index objects (#48149)

Author: jorisvandenbossche

doc/source/whatsnew/v1.4.4.rst

@@ -16,6 +16,7 @@ Fixed regressions
 ~~~~~~~~~~~~~~~~~
 - Fixed regression in taking NULL :class:`objects` from a :class:`DataFrame` causing a segmentation violation. These NULL values are created by :meth:`numpy.empty_like` (:issue:`46848`)
 - Fixed regression in :func:`concat` materializing :class:`Index` during sorting even if :class:`Index` was already sorted (:issue:`47501`)
+- Fixed regression in calling bitwise numpy ufuncs (for example, ``np.bitwise_and``) on Index objects (:issue:`46769`)
 - Fixed regression in :func:`cut` using a ``datetime64`` IntervalIndex as bins (:issue:`46218`)
 - Fixed regression in :meth:`DataFrame.select_dtypes` where ``include="number"`` included :class:`BooleanDtype` (:issue:`46870`)
 - Fixed regression in :meth:`DataFrame.loc` not updating the cache correctly after values were set (:issue:`47867`)

pandas/core/indexes/base.py

@@ -939,11 +939,19 @@ def __array_ufunc__(self, ufunc: np.ufunc, method: str_t, *inputs, **kwargs):
         if any(isinstance(other, (ABCSeries, ABCDataFrame)) for other in inputs):
             return NotImplemented
 
-        result = arraylike.maybe_dispatch_ufunc_to_dunder_op(
-            self, ufunc, method, *inputs, **kwargs
-        )
-        if result is not NotImplemented:
-            return result
+        # TODO(2.0) the 'and', 'or' and 'xor' dunder methods are currently set
+        # operations and not logical operations, so don't dispatch
+        # This is deprecated, so this full 'if' clause can be removed once
+        # deprecation is enforced in 2.0
+        if not (
+            method == "__call__"
+            and ufunc in (np.bitwise_and, np.bitwise_or, np.bitwise_xor)
+        ):
+            result = arraylike.maybe_dispatch_ufunc_to_dunder_op(
+                self, ufunc, method, *inputs, **kwargs
+            )
+            if result is not NotImplemented:
+                return result
 
         if "out" in kwargs:
             # e.g. test_dti_isub_tdi

pandas/tests/indexes/test_numpy_compat.py

@@ -178,3 +178,16 @@ def test_numpy_ufuncs_reductions(index, func, request):
         assert isna(expected)
     else:
         assert result == expected
+
+
+@pytest.mark.parametrize("func", [np.bitwise_and, np.bitwise_or, np.bitwise_xor])
+def test_numpy_ufuncs_bitwise(func):
+    # https://github.com/pandas-dev/pandas/issues/46769
+    idx1 = Index([1, 2, 3, 4], dtype="int64")
+    idx2 = Index([3, 4, 5, 6], dtype="int64")
+
+    with tm.assert_produces_warning(None):
+        result = func(idx1, idx2)
+
+    expected = Index(func(idx1.values, idx2.values))
+    tm.assert_index_equal(result, expected)