DEPR: deprecate unused errors in NDFrame.where/mask

doc/source/whatsnew/v1.5.0.rst

@@ -771,6 +771,7 @@ Other Deprecations
 - Clarified warning from :func:`to_datetime` when delimited dates can't be parsed in accordance to specified ``dayfirst`` argument (:issue:`46210`)
 - Deprecated :class:`Series` and :class:`Resampler` reducers (e.g. ``min``, ``max``, ``sum``, ``mean``) raising a ``NotImplementedError`` when the dtype is non-numric and ``numeric_only=True`` is provided; this will raise a ``TypeError`` in a future version (:issue:`47500`)
 - Deprecated :meth:`Series.rank` returning an empty result when the dtype is non-numeric and ``numeric_only=True`` is provided; this will raise a ``TypeError`` in a future version (:issue:`47500`)
+- Deprecated argument ``errors`` for :meth:`Series.mask`, :meth:`Series.where`, :meth:`DataFrame.mask`, and :meth:`DataFrame.where` as ``errors`` had no effect on this methods (:issue:`47728`)
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_150.performance:

pandas/core/frame.py

@@ -11788,6 +11788,7 @@ def where(
         ...
 
     # error: Signature of "where" incompatible with supertype "NDFrame"
+    @deprecate_kwarg(old_arg_name="errors", new_arg_name=None)
     @deprecate_nonkeyword_arguments(
         version=None, allowed_args=["self", "cond", "other"]
     )
@@ -11807,7 +11808,6 @@ def where(  # type: ignore[override]
             inplace=inplace,
             axis=axis,
             level=level,
-            errors=errors,
             try_cast=try_cast,
         )
 
@@ -11854,6 +11854,7 @@ def mask(
         ...
 
     # error: Signature of "mask" incompatible with supertype "NDFrame"
+    @deprecate_kwarg(old_arg_name="errors", new_arg_name=None)
     @deprecate_nonkeyword_arguments(
         version=None, allowed_args=["self", "cond", "other"]
     )
@@ -11873,7 +11874,6 @@ def mask(  # type: ignore[override]
             inplace=inplace,
             axis=axis,
             level=level,
-            errors=errors,
             try_cast=try_cast,
         )
 

pandas/core/generic.py

@@ -9381,7 +9381,6 @@ def _where(
         inplace=False,
         axis=None,
         level=None,
-        errors: IgnoreRaise | lib.NoDefault = "raise",
     ):
         """
         Equivalent to public method `where`, except that `other` is not
@@ -9548,6 +9547,7 @@ def where(
     ) -> NDFrameT | None:
         ...
 
+    @deprecate_kwarg(old_arg_name="errors", new_arg_name=None)
     @deprecate_nonkeyword_arguments(
         version=None, allowed_args=["self", "cond", "other"]
     )
@@ -9599,6 +9599,9 @@ def where(
             - 'raise' : allow exceptions to be raised.
             - 'ignore' : suppress exceptions. On error return original object.
 
+            .. deprecated:: 1.5.0
+               This argument had no effect.
+
         try_cast : bool, default None
             Try to cast the result back to the input type (if possible).
 
@@ -9721,7 +9724,7 @@ def where(
                 stacklevel=find_stack_level(),
             )
 
-        return self._where(cond, other, inplace, axis, level, errors=errors)
+        return self._where(cond, other, inplace, axis, level)
 
     @overload
     def mask(
@@ -9765,6 +9768,7 @@ def mask(
     ) -> NDFrameT | None:
         ...
 
+    @deprecate_kwarg(old_arg_name="errors", new_arg_name=None)
     @deprecate_nonkeyword_arguments(
         version=None, allowed_args=["self", "cond", "other"]
     )
@@ -9808,7 +9812,6 @@ def mask(
             inplace=inplace,
             axis=axis,
             level=level,
-            errors=errors,
         )
 
     @doc(klass=_shared_doc_kwargs["klass"])

pandas/core/series.py

@@ -61,6 +61,7 @@
 from pandas.util._decorators import (
     Appender,
     Substitution,
+    deprecate_kwarg,
     deprecate_nonkeyword_arguments,
     doc,
 )
@@ -6069,6 +6070,7 @@ def where(
         ...
 
     # error: Signature of "where" incompatible with supertype "NDFrame"
+    @deprecate_kwarg(old_arg_name="errors", new_arg_name=None)
     @deprecate_nonkeyword_arguments(
         version=None, allowed_args=["self", "cond", "other"]
     )
@@ -6088,7 +6090,6 @@ def where(  # type: ignore[override]
             inplace=inplace,
             axis=axis,
             level=level,
-            errors=errors,
             try_cast=try_cast,
         )
 
@@ -6135,6 +6136,7 @@ def mask(
         ...
 
     # error: Signature of "mask" incompatible with supertype "NDFrame"
+    @deprecate_kwarg(old_arg_name="errors", new_arg_name=None)
     @deprecate_nonkeyword_arguments(
         version=None, allowed_args=["self", "cond", "other"]
     )
@@ -6154,7 +6156,6 @@ def mask(  # type: ignore[override]
             inplace=inplace,
             axis=axis,
             level=level,
-            errors=errors,
             try_cast=try_cast,
         )
 

pandas/tests/frame/indexing/test_where.py

@@ -1035,3 +1035,17 @@ def test_where_dt64_2d():
     mask[:] = True
     expected = df
     _check_where_equivalences(df, mask, other, expected)
+
+
+def test_where_mask_deprecated(frame_or_series):
+    # GH 47728
+    obj = DataFrame(np.random.randn(4, 3))
+    obj = tm.get_obj(obj, frame_or_series)
+
+    mask = obj > 0
+
+    with tm.assert_produces_warning(FutureWarning):
+        obj.where(mask, -1, errors="raise")
+
+    with tm.assert_produces_warning(FutureWarning):
+        obj.mask(mask, -1, errors="raise")