DEPR: remove nthreads kwarg from read_feather (pandas-dev#29728)

Author: jbrockmendel

doc/source/whatsnew/v1.0.0.rst

@@ -323,6 +323,7 @@ or ``matplotlib.Axes.plot``. See :ref:`plotting.formatters` for more.
 - Removed previously deprecated :func:`pandas.tseries.plotting.tsplot` (:issue:`18627`)
 - Removed the previously deprecated ``reduce`` and ``broadcast`` arguments from :meth:`DataFrame.apply` (:issue:`18577`)
 - Removed the previously deprecated ``assert_raises_regex`` function in ``pandas.util.testing`` (:issue:`29174`)
+- Removed previously deprecated "nthreads" argument from :func:`read_feather`, use "use_threads" instead (:issue:`23053`)
 - Removed :meth:`Index.is_lexsorted_for_tuple` (:issue:`29305`)
 - Removed support for nexted renaming in :meth:`DataFrame.aggregate`, :meth:`Series.aggregate`, :meth:`DataFrameGroupBy.aggregate`, :meth:`SeriesGroupBy.aggregate`, :meth:`Rolling.aggregate` (:issue:`29608`)
 - Removed previously deprecated "order" argument from :func:`factorize` (:issue:`19751`)

pandas/io/feather_format.py

@@ -3,7 +3,6 @@
 from distutils.version import LooseVersion
 
 from pandas.compat._optional import import_optional_dependency
-from pandas.util._decorators import deprecate_kwarg
 
 from pandas import DataFrame, Int64Index, RangeIndex
 
@@ -66,7 +65,6 @@ def to_feather(df: DataFrame, path):
     feather.write_feather(df, path)
 
 
-@deprecate_kwarg(old_arg_name="nthreads", new_arg_name="use_threads")
 def read_feather(path, columns=None, use_threads=True):
     """
     Load a feather-format object from the file path.
@@ -89,11 +87,6 @@ def read_feather(path, columns=None, use_threads=True):
         If not provided, all columns are read.
 
         .. versionadded:: 0.24.0
-    nthreads : int, default 1
-        Number of CPU threads to use when reading to pandas.DataFrame.
-
-       .. versionadded:: 0.21.0
-       .. deprecated:: 0.24.0
     use_threads : bool, default True
         Whether to parallelize reading using multiple threads.
 

pandas/tests/io/test_feather.py

@@ -107,23 +107,6 @@ def test_unsupported_other(self):
         # Some versions raise ValueError, others raise ArrowInvalid.
         self.check_error_on_write(df, Exception)
 
-    def test_rw_nthreads(self):
-        df = pd.DataFrame({"A": np.arange(100000)})
-        expected_warning = (
-            "the 'nthreads' keyword is deprecated, use 'use_threads' instead"
-        )
-        # TODO: make the warning work with check_stacklevel=True
-        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False) as w:
-            self.check_round_trip(df, nthreads=2)
-        # we have an extra FutureWarning because of #GH23752
-        assert any(expected_warning in str(x) for x in w)
-
-        # TODO: make the warning work with check_stacklevel=True
-        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False) as w:
-            self.check_round_trip(df, nthreads=1)
-        # we have an extra FutureWarnings because of #GH23752
-        assert any(expected_warning in str(x) for x in w)
-
     def test_rw_use_threads(self):
         df = pd.DataFrame({"A": np.arange(100000)})
         self.check_round_trip(df, use_threads=True)