COMPAT: Fix numpy 2.1 timedelta * DateOffset (#59441)

Author: mroeschke

pandas/core/arrays/timedeltas.py

@@ -467,6 +467,10 @@ def __mul__(self, other) -> Self:
  if is_scalar(other):
  # numpy will accept float and int, raise TypeError for others
  result = self._ndarray * other
+ if result.dtype.kind != "m":
+ # numpy >= 2.1 may not raise a TypeError
+ # and seems to dispatch to others.__rmul__?
+ raise TypeError(f"Cannot multiply with {type(other).__name__}")
  freq = None
  if self.freq is not None and not isna(other):
  freq = self.freq * other
@@ -494,6 +498,10 @@ def __mul__(self, other) -> Self:
 
  # numpy will accept float or int dtype, raise TypeError for others
  result = self._ndarray * other
+ if result.dtype.kind != "m":
+ # numpy >= 2.1 may not raise a TypeError
+ # and seems to dispatch to others.__rmul__?
+ raise TypeError(f"Cannot multiply with {type(other).__name__}")
  return type(self)._simple_new(result, dtype=result.dtype)
 
  __rmul__ = __mul__

pandas/tests/arithmetic/test_timedelta64.py

@@ -1460,7 +1460,13 @@ def test_td64arr_mul_int(self, box_with_array):
  def test_td64arr_mul_tdlike_scalar_raises(self, two_hours, box_with_array):
  rng = timedelta_range("1 days", "10 days", name="foo")
  rng = tm.box_expected(rng, box_with_array)
- msg = "argument must be an integer|cannot use operands with types dtype"
+ msg = "|".join(
+ [
+ "argument must be an integer",
+ "cannot use operands with types dtype",
+ "Cannot multiply with",
+ ]
+ )
  with pytest.raises(TypeError, match=msg):
  rng * two_hours