feat(rust, python): add sort for struct dtype (#7021)

polars/polars-core/src/series/implementations/struct_.rs

@@ -362,4 +362,24 @@ impl SeriesTrait for SeriesWrap<StructChunked> {
     fn as_any(&self) -> &dyn Any {
         &self.0
     }
+
+    fn sort_with(&self, options: SortOptions) -> Series {
+        let df = self.0.clone().unnest();
+
+        let desc = if options.descending {
+            vec![true; df.width()]
+        } else {
+            vec![false; df.width()]
+        };
+        let out = df
+            .sort_impl(
+                df.columns.clone(),
+                desc,
+                options.nulls_last,
+                None,
+                options.multithreaded,
+            )
+            .unwrap();
+        StructChunked::new_unchecked(self.name(), &out.columns).into_series()
+    }
 }

py-polars/tests/unit/datatypes/test_struct.py

@@ -803,3 +803,12 @@ def test_struct_concat_self_no_rechunk() -> None:
     out = pl.concat([df, df], rechunk=False)
     assert out.dtypes == [pl.Struct([pl.Field("a", pl.Int64)])]
     assert out.to_dict(False) == {"A": [{"a": 1}, {"a": 1}]}
+
+
+def test_sort_structs() -> None:
+    assert pl.DataFrame(
+        {"sex": ["male", "female", "female"], "age": [22, 38, 26]}
+    ).select(pl.struct(["sex", "age"]).sort()).unnest("sex").to_dict(False) == {
+        "sex": ["female", "female", "male"],
+        "age": [26, 38, 22],
+    }

py-polars/tests/unit/test_errors.py

@@ -65,14 +65,6 @@ def test_string_numeric_comp_err() -> None:
         pl.DataFrame({"a": [1.1, 21, 31, 21, 51, 61, 71, 81]}).select(pl.col("a") < "9")
 
 
-def test_panic_exception() -> None:
-    with pytest.raises(
-        pl.PanicException,
-        match=r"""this operation is not implemented/valid for this dtype: .*""",
-    ):
-        pl.struct(pl.Series("a", [1, 2, 3]), eager=True).sort()
-
-
 @typing.no_type_check
 def test_join_lazy_on_df() -> None:
     df_left = pl.DataFrame(