Fix array_sort for empty record batch

Author: joroKr21

datafusion/functions-array/src/sort.rs

@@ -98,6 +98,12 @@ pub fn array_sort_inner(args: &[ArrayRef]) -> Result<ArrayRef> {
         return exec_err!("array_sort expects one to three arguments");
     }
 
+    let list_array = as_list_array(&args[0])?;
+    let row_count = list_array.len();
+    if row_count == 0 || list_array.value_type().is_null() {
+        return Ok(Arc::clone(&args[0]));
+    }
+
     let sort_option = match args.len() {
         1 => None,
         2 => {
@@ -118,12 +124,6 @@ pub fn array_sort_inner(args: &[ArrayRef]) -> Result<ArrayRef> {
         _ => return exec_err!("array_sort expects 1 to 3 arguments"),
     };
 
-    let list_array = as_list_array(&args[0])?;
-    let row_count = list_array.len();
-    if row_count == 0 {
-        return Ok(args[0].clone());
-    }
-
     let mut array_lengths = vec![];
     let mut arrays = vec![];
     let mut valid = BooleanBufferBuilder::new(row_count);

datafusion/sqllogictest/test_files/array.slt

@@ -2038,6 +2038,11 @@ NULL
 [, 51, 52, 54, 55, 56, 57, 58, 59, 60]
 [61, 62, 63, 64, 65, 66, 67, 68, 69, 70]
 
+# test with empty table
+query ?
+select array_sort(column1, 'DESC', 'NULLS FIRST') from arrays_values where false;
+----
+
 # test with empty array
 query ?
 select array_sort([]);