MDEV-31214 Recursive CTE execution is interrupted without errors or warnings

mysql-test/main/cte_recursive.result

@@ -1214,6 +1214,8 @@ generation	name
 2	Grandma Ann
 2	Grandma Sally
 2	Grandpa Ben
+Warnings:
+Warning	1931	Query execution was interrupted. The query exceeded max_recursive_iterations = 1. The query result may be incomplete
 # query with recursive tables using key access
 alter table folks add primary key (id);
 explain
@@ -2592,6 +2594,8 @@ select * from applied_modules;
 m
 m1
 m2
+Warnings:
+Warning	1931	Query execution was interrupted. The query exceeded max_recursive_iterations = 2. The query result may be incomplete
 drop table value_nodes, module_nodes, module_arguments, module_results;
 #
 # mdev-12519: recursive references in subqueries 

sql/sql_derived.cc

@@ -1142,7 +1142,14 @@ bool TABLE_LIST::fill_recursive(THD *thd)
   while (!rc && !with->all_are_stabilized())
   {
     if (with->level > thd->variables.max_recursive_iterations)
+    {
+      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
+                          ER_QUERY_RESULT_INCOMPLETE,
+                          ER_THD(thd, ER_QUERY_RESULT_INCOMPLETE),
+                          "max_recursive_iterations =",
+                          (ulonglong)thd->variables.max_recursive_iterations);
       break;
+    }
     with->prepare_for_next_iteration();
     rc= unit->exec_recursive();
   }