orm: fix crash when working with array field (fix #22822) (#22824)

cmd/tools/vtest-self.v

@@ -179,6 +179,7 @@ const skip_with_fsanitize_memory = [
 	'vlib/v/tests/sql_statement_inside_fn_call_test.v',
 	'vlib/v/tests/orm_stmt_wrong_return_checking_test.v',
 	'vlib/v/tests/orm_table_name_test.v',
+	'vlib/v/tests/orm_array_field_test.v',
 	'vlib/v/tests/orm_handle_error_for_select_from_not_created_table_test.v',
 	'vlib/v/tests/orm_create_several_tables_test.v',
 	'vlib/vweb/tests/vweb_test.v',
@@ -271,6 +272,7 @@ const skip_on_ubuntu_musl = [
 	'vlib/v/tests/orm_joined_tables_select_test.v',
 	'vlib/v/tests/orm_stmt_wrong_return_checking_test.v',
 	'vlib/v/tests/orm_table_name_test.v',
+	'vlib/v/tests/orm_array_field_test.v',
 	'vlib/v/tests/orm_handle_error_for_select_from_not_created_table_test.v',
 	'vlib/v/tests/orm_create_several_tables_test.v',
 	'vlib/v/tests/sql_statement_inside_fn_call_test.v',

vlib/v/gen/c/orm.v

@@ -319,7 +319,9 @@ fn (mut g Gen) write_orm_insert_with_last_ids(node ast.SqlStmtLine, connection_v
 			if field.typ.has_flag(.option) {
 				opt_fields << arrs.len
 			}
-			arrs << unsafe { node.sub_structs[int(field.typ)] }
+			if node.sub_structs.len > 0 {
+				arrs << unsafe { node.sub_structs[int(field.typ)] }
+			}
 			field_names << field.name
 		}
 	}

vlib/v/tests/orm_array_field_test.v

@@ -0,0 +1,35 @@
+import time
+import db.sqlite
+
+@[table: 'task_metadata']
+struct TaskMetadata {
+	id         string @[primary]
+	task_id    string
+	key        string
+	value      string
+	created_at time.Time @[default: 'CURRENT_TIME']
+	updated_at time.Time @[default: 'CURRENT_TIME']
+}
+
+@[table: 'tasks']
+struct Task {
+	id       string @[primary]
+	name     string
+	metadata []TaskMetadata @[fkey: 'task_id']
+}
+
+struct MyService {
+mut:
+	db sqlite.DB
+}
+
+pub fn (s MyService) create(record Task) int {
+	result := sql s.db {
+		insert record into Task
+	} or { return -1 }
+	return result
+}
+
+fn test_main() {
+	assert true
+}