BUG: Fix implementation of temp_setattr (#45954)

Author: rhshadrach

pandas/core/common.py

@@ -545,8 +545,10 @@ def temp_setattr(obj, attr: str, value) -> Iterator[None]:
     """
     old_value = getattr(obj, attr)
     setattr(obj, attr, value)
-    yield obj
-    setattr(obj, attr, old_value)
+    try:
+        yield obj
+    finally:
+        setattr(obj, attr, old_value)
 
 
 def require_length_match(data, index: Index):

pandas/tests/test_common.py

@@ -213,3 +213,19 @@ def test_frozenlist(self):
         result = df[frozen]
         expected = df[[]]
         tm.assert_frame_equal(result, expected)
+
+
+@pytest.mark.parametrize("with_exception", [True, False])
+def test_temp_setattr(with_exception):
+    # GH#45954
+    ser = Series(dtype=object)
+    ser.name = "first"
+    # Raise a ValueError in either case to satisfy pytest.raises
+    match = "Inside exception raised" if with_exception else "Outside exception raised"
+    with pytest.raises(ValueError, match=match):
+        with com.temp_setattr(ser, "name", "second"):
+            assert ser.name == "second"
+            if with_exception:
+                raise ValueError("Inside exception raised")
+        raise ValueError("Outside exception raised")
+    assert ser.name == "first"