Fix rolling(min_periods=) with int and null data with mode.pandas_compat (rapidsai#17822)

closes rapidsai#17786

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

Approvers:
  - Vyas Ramasubramani (https://github.com/vyasr)
  - GALI PREM SAGAR (https://github.com/galipremsagar)
  - Lawrence Mitchell (https://github.com/wence-)

URL: rapidsai#17822

Author: mroeschke

python/cudf/cudf/core/window/rolling.py

@@ -23,6 +23,7 @@
 
 if TYPE_CHECKING:
     from cudf.core.column.column import ColumnBase
+    from cudf.core.indexed_frame import IndexedFrame
 
 
 class _RollingBase:
@@ -205,7 +206,7 @@ class Rolling(GetAttrGetItemMixin, _RollingBase, Reducible):
 
     def __init__(
         self,
-        obj,
+        obj: IndexedFrame,
         window,
         min_periods=None,
         center: bool = False,
@@ -216,7 +217,9 @@ def __init__(
         step: int | None = None,
         method: str = "single",
     ):
-        self.obj = obj
+        if cudf.get_option("mode.pandas_compatible"):
+            obj = obj.nans_to_nulls()
+        self.obj = obj  # type: ignore[assignment]
         self.window = window
         self.min_periods = min_periods
         self.center = center

python/cudf/cudf/tests/test_rolling.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2021-2024, NVIDIA CORPORATION.
+# Copyright (c) 2021-2025, NVIDIA CORPORATION.
 
 import math
 
@@ -517,3 +517,16 @@ def test_rolling_series():
     actual = df.groupby("b")["a"].rolling(5).mean()
 
     assert_eq(expected, actual)
+
+
+@pytest.mark.parametrize("klass", ["DataFrame", "Series"])
+def test_pandas_compat_int_nan_min_periods(klass):
+    data = [None, 1, 2, None, 4, 6, 11]
+    with cudf.option_context("mode.pandas_compatible", True):
+        result = getattr(cudf, klass)(data).rolling(2, min_periods=1).sum()
+    expected = getattr(pd, klass)(data).rolling(2, min_periods=1).sum()
+    assert_eq(result, expected)
+
+    result = getattr(cudf, klass)(data).rolling(2, min_periods=1).sum()
+    expected = getattr(cudf, klass)([None, 1, 3, 2, 4, 10, 17])
+    assert_eq(result, expected)