Ensure arrays passed to MutableArrayData have same type (#5091)

arrow-data/src/transform/mod.rs

@@ -354,6 +354,14 @@ impl<'a> MutableArrayData<'a> {
     ) -> Self {
         let data_type = arrays[0].data_type();
 
+        for a in arrays.iter().skip(1) {
+            assert_eq!(
+                data_type,
+                a.data_type(),
+                "Arrays with inconsistent types passed to MutableArrayData"
+            )
+        }
+
         // if any of the arrays has nulls, insertions from any array requires setting bits
         // as there is at least one array with nulls.
         let use_nulls = use_nulls | arrays.iter().any(|array| array.null_count() > 0);

arrow/tests/array_transform.rs

@@ -975,6 +975,14 @@ fn test_extend_nulls_panic() {
     mutable.extend_nulls(2);
 }
 
+#[test]
+#[should_panic(expected = "Arrays with inconsistent types passed to MutableArrayData")]
+fn test_mixed_types() {
+    let a = StringArray::from(vec!["abc", "def"]).to_data();
+    let b = Int32Array::from(vec![1, 2, 3]).to_data();
+    MutableArrayData::new(vec![&a, &b], false, 4);
+}
+
 /*
 // this is an old test used on a meanwhile removed dead code
 // that is still useful when `MutableArrayData` supports fixed-size lists.