fix: Return correct dtype for s.clear() when dtype is Object (#15315

)

crates/polars-core/src/series/mod.rs

@@ -157,17 +157,17 @@ impl Series {
     }
 
     pub fn clear(&self) -> Series {
-        // Only the inner of objects know their type, so use this hack.
-        #[cfg(feature = "object")]
-        if matches!(self.dtype(), DataType::Object(_, _)) {
-            return if self.is_empty() {
-                self.clone()
-            } else {
-                let av = self.get(0).unwrap();
-                Series::new(self.name(), [av]).slice(0, 0)
-            };
+        if self.is_empty() {
+            self.clone()
+        } else {
+            match self.dtype() {
+                #[cfg(feature = "object")]
+                DataType::Object(_, _) => self
+                    .take(&ChunkedArray::<IdxType>::new_vec("", vec![]))
+                    .unwrap(),
+                dt => Series::new_empty(self.name(), dt),
+            }
         }
-        Series::new_empty(self.name(), self.dtype())
     }
 
     #[doc(hidden)]

py-polars/tests/unit/operations/test_clear.py

@@ -65,7 +65,6 @@ def test_clear_lf() -> None:
     assert ldfe.collect().rows() == [(None, None, None), (None, None, None)]
 
 
-@pytest.mark.skip("Currently bugged: https://github.com/pola-rs/polars/issues/15303")
 def test_clear_series_object_starting_with_null() -> None:
     s = pl.Series([None, object()])