fix: Fix gather of Scalar null + idx w/ validity (#19823)

pola-rs · Nov 16, 2024 · 9311cdd · 9311cdd
1 parent 7482315
commit 9311cdd
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/crates/polars-core/src/frame/column/mod.rs b/crates/polars-core/src/frame/column/mod.rs
@@ -552,7 +552,7 @@ impl Column {
                 );
 
                 // We need to make sure that null values in `idx` become null values in the result
-                if idxs_null_count == 0 {
+                if idxs_null_count == 0 || scalar.has_nulls() {
                     scalar.into_column()
                 } else if idxs_null_count == idxs_length {
                     scalar.into_nulls().into_column()

diff --git a/py-polars/tests/unit/operations/test_join.py b/py-polars/tests/unit/operations/test_join.py
@@ -1123,3 +1123,13 @@ def test_array_explode_join_19763() -> None:
     q = q.join(pl.LazyFrame({"k": [1, 2]}), on="k")
 
     assert_frame_equal(q.collect().sort("k"), pl.DataFrame({"k": [1, 2]}))
+
+
+def test_join_full_19814() -> None:
+    a = pl.LazyFrame(
+        {"a": [1], "c": [None]}, schema={"a": pl.Int64, "c": pl.Categorical}
+    )
+    b = pl.LazyFrame({"a": [1, 3, 4]})
+    assert a.join(b, on="a", how="full", coalesce=True).collect().to_dict(
+        as_series=False
+    ) == {"a": [1, 3, 4], "c": [None, None, None]}