BUG: pivot dropping wrong column level with numeric columns and ea dtype (#56528)

Author: phofl

doc/source/whatsnew/v2.2.0.rst

@@ -676,6 +676,7 @@ Reshaping
 - Bug in :meth:`DataFrame.melt` where an exception was raised if ``var_name`` was not a string (:issue:`55948`)
 - Bug in :meth:`DataFrame.melt` where it would not preserve the datetime (:issue:`55254`)
 - Bug in :meth:`DataFrame.pivot_table` where the row margin is incorrect when the columns have numeric names (:issue:`26568`)
+- Bug in :meth:`DataFrame.pivot` with numeric columns and extension dtype for data (:issue:`56528`)
 
 Sparse
 ^^^^^^

pandas/core/reshape/reshape.py

@@ -572,7 +572,7 @@ def _unstack_extension_series(
 
     # equiv: result.droplevel(level=0, axis=1)
     #  but this avoids an extra copy
-    result.columns = result.columns.droplevel(0)
+    result.columns = result.columns._drop_level_numbers([0])
     return result
 
 

pandas/tests/reshape/test_pivot.py

@@ -2520,11 +2520,12 @@ def test_pivot_empty(self):
         expected = DataFrame(index=[], columns=[])
         tm.assert_frame_equal(result, expected, check_names=False)
 
-    def test_pivot_integer_bug(self):
-        df = DataFrame(data=[("A", "1", "A1"), ("B", "2", "B2")])
+    @pytest.mark.parametrize("dtype", [object, "string"])
+    def test_pivot_integer_bug(self, dtype):
+        df = DataFrame(data=[("A", "1", "A1"), ("B", "2", "B2")], dtype=dtype)
 
         result = df.pivot(index=1, columns=0, values=2)
-        tm.assert_index_equal(result.columns, Index(["A", "B"], name=0))
+        tm.assert_index_equal(result.columns, Index(["A", "B"], name=0, dtype=dtype))
 
     def test_pivot_index_none(self):
         # GH#3962