fix: Fix incorrect reverse on struct containing NULLs (#19446)

pola-rs · Oct 25, 2024 · 34b1dc5 · 34b1dc5
1 parent 25b54dc
commit 34b1dc5
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/crates/polars-core/src/series/implementations/struct_.rs b/crates/polars-core/src/series/implementations/struct_.rs
@@ -232,7 +232,14 @@ impl SeriesTrait for SeriesWrap<StructChunked> {
     }
 
     fn reverse(&self) -> Series {
-        self.0._apply_fields(|s| s.reverse()).unwrap().into_series()
+        let validity = self
+            .rechunk_validity()
+            .map(|x| x.into_iter().rev().collect::<Bitmap>());
+        self.0
+            ._apply_fields(|s| s.reverse())
+            .unwrap()
+            .with_outer_validity(validity)
+            .into_series()
     }
 
     fn shift(&self, periods: i64) -> Series {

diff --git a/py-polars/tests/unit/datatypes/test_struct.py b/py-polars/tests/unit/datatypes/test_struct.py
@@ -1149,3 +1149,10 @@ def test_list_to_struct_19208() -> None:
     ).to_dict(as_series=False) == {
         "nested": [{"field_0": {"a": 1}}, {"field_0": None}, {"field_0": {"a": 3}}]
     }
+
+
+def test_struct_reverse_outer_validity_19445() -> None:
+    assert_series_equal(
+        pl.Series([{"a": 1}, None]).reverse(),
+        pl.Series([None, {"a": 1}]),
+    )