Deprecate delim_whitespace in read_csv for pandas 2.2 (#14986)

Toward pandas 2.2 compat: Deprecated in pandas in pandas-dev/pandas#56557

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)

Approvers:
  - Ashwin Srinath (https://github.com/shwina)

URL: #14986

python/cudf/cudf/io/csv.py

@@ -1,5 +1,6 @@
-# Copyright (c) 2018-2023, NVIDIA CORPORATION.
+# Copyright (c) 2018-2024, NVIDIA CORPORATION.
 
+import warnings
 from collections import abc
 from io import BytesIO, StringIO
 
@@ -55,6 +56,13 @@ def read_csv(
 ):
     """{docstring}"""
 
+    if delim_whitespace is not False:
+        warnings.warn(
+            "The 'delim_whitespace' keyword in pd.read_csv is deprecated and "
+            "will be removed in a future version. Use ``sep='\\s+'`` instead",
+            FutureWarning,
+        )
+
     if use_python_file_object and bytes_per_thread is not None:
         raise ValueError(
             "bytes_per_thread is only supported when "

python/cudf/cudf/tests/test_csv.py

@@ -17,8 +17,12 @@
 
 import cudf
 from cudf import read_csv
-from cudf.core._compat import PANDAS_GE_200
-from cudf.testing._utils import assert_eq, assert_exceptions_equal
+from cudf.core._compat import PANDAS_GE_200, PANDAS_GE_220
+from cudf.testing._utils import (
+    assert_eq,
+    assert_exceptions_equal,
+    expect_warning_if,
+)
 
 
 def make_numeric_dataframe(nrows, dtype):
@@ -1263,20 +1267,28 @@ def test_csv_reader_delim_whitespace():
     buffer = "1    2  3\n4  5 6"
 
     # with header row
-    cu_df = read_csv(StringIO(buffer), delim_whitespace=True)
-    pd_df = pd.read_csv(StringIO(buffer), delim_whitespace=True)
+    with pytest.warns(FutureWarning):
+        cu_df = read_csv(StringIO(buffer), delim_whitespace=True)
+    with expect_warning_if(PANDAS_GE_220):
+        pd_df = pd.read_csv(StringIO(buffer), delim_whitespace=True)
     assert_eq(pd_df, cu_df)
 
     # without header row
-    cu_df = read_csv(StringIO(buffer), delim_whitespace=True, header=None)
-    pd_df = pd.read_csv(StringIO(buffer), delim_whitespace=True, header=None)
+    with pytest.warns(FutureWarning):
+        cu_df = read_csv(StringIO(buffer), delim_whitespace=True, header=None)
+    with expect_warning_if(PANDAS_GE_220):
+        pd_df = pd.read_csv(
+            StringIO(buffer), delim_whitespace=True, header=None
+        )
     assert pd_df.shape == cu_df.shape
 
     # should raise an error if used with delimiter or sep
     with pytest.raises(ValueError):
-        read_csv(StringIO(buffer), delim_whitespace=True, delimiter=" ")
+        with pytest.warns(FutureWarning):
+            read_csv(StringIO(buffer), delim_whitespace=True, delimiter=" ")
     with pytest.raises(ValueError):
-        read_csv(StringIO(buffer), delim_whitespace=True, sep=" ")
+        with pytest.warns(FutureWarning):
+            read_csv(StringIO(buffer), delim_whitespace=True, sep=" ")
 
 
 def test_csv_reader_unnamed_cols():