fix memcpy of multiple chunks; closes 1396

polars/polars-core/src/chunked_array/ops/sort.rs

@@ -129,9 +129,9 @@ where
 
     let mut offset = 0;
     ca.downcast_iter().for_each(|arr| {
-        let values = arr.values();
-        let len = arr.len();
-        (vals_slice[offset..len]).copy_from_slice(values);
+        let values = arr.values().as_slice();
+        let len = values.len();
+        (vals_slice[offset..offset + len]).copy_from_slice(values);
         offset += len;
     });
     vals

polars/polars-core/src/lib.rs

@@ -16,6 +16,8 @@ pub mod prelude;
 pub mod serde;
 pub mod series;
 pub mod testing;
+#[cfg(test)]
+mod tests;
 pub(crate) mod vector_hasher;
 
 #[cfg(feature = "dtype-categorical")]

polars/polars-core/src/tests.rs

@@ -0,0 +1,17 @@
+use crate::prelude::*;
+
+#[test]
+fn test_initial_empty_sort() -> Result<()> {
+    // https://github.com/pola-rs/polars/issues/1396
+    let data = vec![1.3; 42];
+    let mut series = Series::new("data", Vec::<f64>::new());
+    let series2 = Series::new("data2", data.clone());
+    let series3 = Series::new("data3", data);
+    let df = DataFrame::new(vec![series2, series3])?;
+
+    for column in df.get_columns().iter() {
+        series.append(column)?;
+    }
+    series.f64()?.sort(false);
+    Ok(())
+}