REGR: revert ExtensionBlock.set to be in-place

Author: jorisvandenbossche

pandas/core/internals/blocks.py

@@ -1589,7 +1589,7 @@ def should_store(self, value: ArrayLike) -> bool:
 
     def set(self, locs, values):
         assert locs.tolist() == [0]
-        self.values[:] = values
+        self.values = values
 
     def putmask(
         self, mask, new, inplace: bool = False, axis: int = 0, transpose: bool = False,

pandas/tests/indexing/test_iloc.py

@@ -694,6 +694,7 @@ def test_series_indexing_zerodim_np_array(self):
         result = s.iloc[np.array(0)]
         assert result == 1
 
+    @pytest.mark.xfail(reason="https://github.com/pandas-dev/pandas/issues/33457")
     def test_iloc_setitem_categorical_updates_inplace(self):
         # Mixed dtype ensures we go through take_split_path in setitem_with_indexer
         cat = pd.Categorical(["A", "B", "C"])