Fix panic on wrong number of arguments to substr (#12837)

Author: eejbyfeldt

datafusion/functions/src/unicode/substr.rs

@@ -84,6 +84,13 @@ impl ScalarUDFImpl for SubstrFunc {
     }
 
     fn coerce_types(&self, arg_types: &[DataType]) -> Result<Vec<DataType>> {
+        if arg_types.len() < 2 || arg_types.len() > 3 {
+            return plan_err!(
+                "The {} function requires 2 or 3 arguments, but got {}.",
+                self.name(),
+                arg_types.len()
+            );
+        }
         let first_data_type = match &arg_types[0] {
             DataType::Null => Ok(DataType::Utf8),
             DataType::LargeUtf8 | DataType::Utf8View | DataType::Utf8 => Ok(arg_types[0].clone()),

datafusion/sqllogictest/test_files/errors.slt

@@ -130,3 +130,6 @@ order by c9
 
 query error DataFusion error: Arrow error: Cast error: Cannot cast string 'foo' to value of Int64 type
 create table foo as values (1), ('foo');
+
+query error No function matches
+select 1 group by substr('');