Review (jreback)

pandas/core/frame.py

@@ -5246,14 +5246,20 @@ def update(self, other, join='left', overwrite=True, filter_func=None,
             If 'raise', will raise a ValueError if the DataFrame and `other`
             both contain non-NA data in the same place.
 
+            .. versionchanged :: 0.24.0
+               Changed from `raise_conflict=False|True` to `errors='ignore'|'raise'`.
+
         Returns
         -------
         None : method directly changes calling object
 
         Raises
         ------
         ValueError
-            When `errors='raise'` and there's overlapping non-NA data.
+            * When `errors='raise'` and there's overlapping non-NA data.
+            * When `errors` is not either `'ignore'` or `'raise'`
+        NotImplementedError
+            * If `join != 'left'`
 
         See Also
         --------
@@ -5324,6 +5330,9 @@ def update(self, other, join='left', overwrite=True, filter_func=None,
         # TODO: Support other joins
         if join != 'left':  # pragma: no cover
             raise NotImplementedError("Only left join is supported")
+        if errors not in ['ignore', 'raise']:
+            raise ValueError("The parameter errors must be either "
+                             "'ignore' or 'raise'")
 
         if not isinstance(other, DataFrame):
             other = DataFrame(other)

pandas/tests/frame/test_combine_concat.py

@@ -313,7 +313,17 @@ def test_update_filtered(self):
                               [1.5, nan, 7.]])
         assert_frame_equal(df, expected)
 
-    def test_update_raise(self):
+    @pytest.mark.parametrize('bad_kwarg, exception, msg', [
+        # errors must be 'ignore' or 'raise'
+        ({'errors': 'something'}, ValueError, 'The parameter errors must.*'),
+        ({'join': 'inner'}, NotImplementedError, 'Only left join is supported')
+    ])
+    def test_update_raise_bad_parameter(self, bad_kwarg, exception, msg):
+        df = DataFrame([[1.5, 1, 3.]])
+        with pytest.raises(exception, match=msg):
+            df.update(df, **bad_kwarg)
+
+    def test_update_raise_on_overlap(self):
         df = DataFrame([[1.5, 1, 3.],
                         [1.5, nan, 3.],
                         [1.5, nan, 3],
@@ -323,8 +333,13 @@ def test_update_raise(self):
                            [nan, 7]], index=[1, 3], columns=[1, 2])
         with pytest.raises(ValueError, match="Data overlaps"):
             df.update(other, errors='raise')
+
+    @pytest.mark.parametrize('raise_conflict', [True, False])
+    def test_update_deprecation(self, raise_conflict):
+        df = DataFrame([[1.5, 1, 3.]])
+        other = DataFrame()
         with tm.assert_produces_warning(FutureWarning):
-            df.update(other, raise_conflict=False)
+            df.update(other, raise_conflict=raise_conflict)
 
     def test_update_from_non_df(self):
         d = {'a': Series([1, 2, 3, 4]), 'b': Series([5, 6, 7, 8])}