BUG: pickling ArrowExtensionArray with _pa_data rename

pandas/core/arrays/arrow/array.py

@@ -433,11 +433,15 @@ def __abs__(self) -> Self:
     # https://issues.apache.org/jira/browse/ARROW-10739 is addressed
     def __getstate__(self):
         state = self.__dict__.copy()
-        state["_data"] = self._pa_array.combine_chunks()
+        state["_pa_array"] = self._pa_array.combine_chunks()
         return state
 
     def __setstate__(self, state) -> None:
-        state["_pa_array"] = pa.chunked_array(state["_data"])
+        if "_data" in state:
+            data = state.pop("_data")
+        else:
+            data = state["_pa_array"]
+        state["_pa_array"] = pa.chunked_array(data)
         self.__dict__.update(state)
 
     def _cmp_method(self, other, op):

pandas/tests/extension/test_arrow.py

@@ -2351,3 +2351,20 @@ def test_concat_empty_arrow_backed_series(dtype):
     expected = ser.copy()
     result = pd.concat([ser[np.array([], dtype=np.bool_)]])
     tm.assert_series_equal(result, expected)
+
+
+# _data was renamed to _pa_data
+class OldArrowExtensionArray(ArrowExtensionArray):
+    def __getstate__(self):
+        state = super().__getstate__()
+        state["_data"] = state.pop("_pa_array")
+        return state
+
+
+def test_pickle_old_arrowextensionarray():
+    data = pa.array([1])
+    expected = OldArrowExtensionArray(data)
+    result = pickle.loads(pickle.dumps(expected))
+    tm.assert_extension_array_equal(result, expected)
+    assert result._pa_array == pa.chunked_array(data)
+    assert not hasattr(result, "_data")