BUG: Series.map is ignoring the na_action keyword (#46860)

Author: stanleycai95

doc/source/whatsnew/v1.5.0.rst

@@ -79,6 +79,7 @@ as seen in the following example.
 
 Other enhancements
 ^^^^^^^^^^^^^^^^^^
+- :meth:`Series.map` now raises when ``arg`` is dict but ``na_action`` is not either ``None`` or ``'ignore'`` (:issue:`46588`)
 - :meth:`MultiIndex.to_frame` now supports the argument ``allow_duplicates`` and raises on duplicate labels if it is missing or False (:issue:`45245`)
 - :class:`StringArray` now accepts array-likes containing nan-likes (``None``, ``np.nan``) for the ``values`` parameter in its constructor in addition to strings and :attr:`pandas.NA`. (:issue:`40839`)
 - Improved the rendering of ``categories`` in :class:`CategoricalIndex` (:issue:`45218`)

pandas/core/base.py

@@ -842,6 +842,12 @@ def _map_values(self, mapper, na_action=None):
                 )
 
         if isinstance(mapper, ABCSeries):
+            if na_action not in (None, "ignore"):
+                msg = (
+                    "na_action must either be 'ignore' or None, "
+                    f"{na_action} was passed"
+                )
+                raise ValueError(msg)
             # Since values were input this means we came from either
             # a dict or a series and mapper should be an index
             if is_categorical_dtype(self.dtype):

pandas/tests/apply/test_invalid_arg.py

@@ -66,6 +66,15 @@ def test_map_with_invalid_na_action_raises():
         s.map(lambda x: x, na_action="____")
 
 
+@pytest.mark.parametrize("input_na_action", ["____", True])
+def test_map_arg_is_dict_with_invalid_na_action_raises(input_na_action):
+    # https://github.com/pandas-dev/pandas/issues/46588
+    s = Series([1, 2, 3])
+    msg = f"na_action must either be 'ignore' or None, {input_na_action} was passed"
+    with pytest.raises(ValueError, match=msg):
+        s.map({1: 2}, na_action=input_na_action)
+
+
 def test_map_categorical_na_action():
     values = Categorical(list("ABBABCD"), categories=list("DCBA"), ordered=True)
     s = Series(values, name="XX", index=list("abcdefg"))