Merge branch 'master' of https://github.com/pandas-dev/pandas into 26395

� Conflicts: �	pandas/tests/indexing/test_at.py

pandas/tests/indexing/test_at.py

@@ -119,6 +119,14 @@ def test_at_frame_raises_key_error2(self):
  with pytest.raises(KeyError, match="^0$"):
  df.loc["a", 0]
 
+ def test_at_getitem_mixed_index_no_fallback(self):
+ # GH#19860
+ ser = Series([1, 2, 3, 4, 5], index=["a", "b", "c", 1, 2])
+ with pytest.raises(KeyError, match="^0$"):
+ ser.at[0]
+ with pytest.raises(KeyError, match="^4$"):
+ ser.at[4]
+
 
 @pytest.mark.parametrize("func", ["at", "loc"])
 def test_at_assign_float_to_int_frame(func):