From ee1482216a2d9ca2e4c6876eef45bcb9ff543d63 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 15 Oct 2025 17:28:13 -0700
Subject: [PATCH 1/2] Deprecate Series.data

---
 docs/cudf/source/user_guide/api_docs/series.rst  | 1 -
 python/cudf/cudf/core/series.py                  | 5 +++++
 python/cudf/cudf/tests/series/test_attributes.py | 6 ++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/docs/cudf/source/user_guide/api_docs/series.rst b/docs/cudf/source/user_guide/api_docs/series.rst
index 546997becc8..19fc8b0f33e 100644
--- a/docs/cudf/source/user_guide/api_docs/series.rst
+++ b/docs/cudf/source/user_guide/api_docs/series.rst
@@ -20,7 +20,6 @@ Attributes
    Series.axes
    Series.index
    Series.values
-   Series.data
    Series.dtype
    Series.dtypes
    Series.shape
diff --git a/python/cudf/cudf/core/series.py b/python/cudf/cudf/core/series.py
index 2616d5cd7a6..0a32121febe 100644
--- a/python/cudf/cudf/core/series.py
+++ b/python/cudf/cudf/core/series.py
@@ -1995,6 +1995,11 @@ def data(self):
         array([1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0,
                0, 0, 4, 0, 0, 0, 0, 0, 0, 0], dtype=uint8)
         """
+        warnings.warn(
+            "Series.data is deprecated and will be removed in a future version. "
+            "Use Series.to_pylibcudf()[0].data() instead.",
+            FutureWarning,
+        )
         return self._column.data
 
     @_performance_tracking
diff --git a/python/cudf/cudf/tests/series/test_attributes.py b/python/cudf/cudf/tests/series/test_attributes.py
index 1d3fa4f81a5..3d464649a5b 100644
--- a/python/cudf/cudf/tests/series/test_attributes.py
+++ b/python/cudf/cudf/tests/series/test_attributes.py
@@ -429,3 +429,9 @@ def test_series_values_property(data):
     gds_vals = gds.values
     assert isinstance(gds_vals, cp.ndarray)
     np.testing.assert_array_equal(gds_vals.get(), pds.values)
+
+
+def test_series_data_property_deprecated():
+    s = cudf.Series([1, 2, 3])
+    with pytest.warns(FutureWarning):
+        s.data

From b86f4297dc5d48a63a82d8359e4ecf9ea1579f1f Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Thu, 16 Oct 2025 09:11:28 -0700
Subject: [PATCH 2/2] Undo API doc change

---
 docs/cudf/source/user_guide/api_docs/series.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/docs/cudf/source/user_guide/api_docs/series.rst b/docs/cudf/source/user_guide/api_docs/series.rst
index 19fc8b0f33e..546997becc8 100644
--- a/docs/cudf/source/user_guide/api_docs/series.rst
+++ b/docs/cudf/source/user_guide/api_docs/series.rst
@@ -20,6 +20,7 @@ Attributes
    Series.axes
    Series.index
    Series.values
+   Series.data
    Series.dtype
    Series.dtypes
    Series.shape