From 32425a473e8a0e9d446508bdaef474bfdb9052ae Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Tue, 7 Jul 2026 21:58:45 +0000
Subject: [PATCH] Support pl.Expr.dt.quarter in cudf_polars

---
 .../cudf_polars/dsl/expressions/datetime.py   | 11 ++++++++++
 .../tests/expressions/test_datetime_basic.py  | 21 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/python/cudf_polars/cudf_polars/dsl/expressions/datetime.py b/python/cudf_polars/cudf_polars/dsl/expressions/datetime.py
index b6b582738188..b7452411e5e7 100644
--- a/python/cudf_polars/cudf_polars/dsl/expressions/datetime.py
+++ b/python/cudf_polars/cudf_polars/dsl/expressions/datetime.py
@@ -145,6 +145,7 @@ def from_polars(cls, obj: polars._expr_nodes.TemporalFunction) -> Self:
         Name.TimeStamp,
         Name.CastTimeUnit,
         Name.Truncate,
+        Name.Quarter,
         *_TOTAL_COMPONENT_NANOSECONDS.keys(),
     }
 
@@ -225,6 +226,16 @@ def do_evaluate(
                 ),
                 dtype=self.dtype,
             )
+        elif self.name is TemporalFunction.Name.Quarter:
+            (column,) = columns
+            return Column(
+                plc.unary.cast(
+                    plc.datetime.extract_quarter(column.obj, stream=df.stream),
+                    self.dtype.plc_type,
+                    stream=df.stream,
+                ),
+                dtype=self.dtype,
+            )
         elif self.name is TemporalFunction.Name.CastTimeUnit:
             (column,) = columns
             return Column(
diff --git a/python/cudf_polars/tests/expressions/test_datetime_basic.py b/python/cudf_polars/tests/expressions/test_datetime_basic.py
index 26d4c01a4766..bdc473ed4d32 100644
--- a/python/cudf_polars/tests/expressions/test_datetime_basic.py
+++ b/python/cudf_polars/tests/expressions/test_datetime_basic.py
@@ -490,6 +490,27 @@ def test_datetime_truncate_unsupported(engine: pl.GPUEngine, every: str):
     assert_ir_translation_raises(q, engine, NotImplementedError)
 
 
+@pytest.mark.parametrize(
+    "dtype", [pl.Date(), pl.Datetime("ms"), pl.Datetime("us"), pl.Datetime("ns")]
+)
+def test_datetime_quarter(engine: pl.GPUEngine, dtype):
+    data = pl.Series(
+        [
+            datetime.date(2001, 1, 1),
+            datetime.date(2001, 3, 31),
+            datetime.date(2001, 4, 1),
+            datetime.date(2001, 6, 30),
+            datetime.date(2001, 9, 15),
+            datetime.date(2001, 12, 27),
+            None,
+        ],
+        dtype=pl.Date(),
+    ).cast(dtype)
+    ldf = pl.LazyFrame({"dates": data})
+    q = ldf.select(pl.col("dates").dt.quarter())
+    assert_gpu_result_equal(q, engine=engine)
+
+
 @pytest.mark.parametrize(
     "datetime_dtype",
     [