MDEV-24538: JSON_LENGTH does not return error upon wrong number of parameters

mysql-test/main/func_json.result

@@ -1289,5 +1289,12 @@ JSON_LOOSE(JSON_EXTRACT(a, '$**.analyzing_range_alternatives'))
 [{"range_scan_alternatives": [{"index": "a_b", "ranges": ["2 <= a <= 2 AND 4 <= b <= 4", "123"], "rowid_ordered": true, "using_mrr": false, "index_only": true, "rows": 1, "cost": 1.1752, "chosen": true}], "analyzing_roworder_intersect": {"cause": "too few roworder scans"}, "analyzing_index_merge_union": [], "test_one_line_array": ["123"]}]
 drop table t200;
 #
+# MDEV-24538: JSON_LENGTH does not return error upon wrong number of parameters
+#
+SELECT JSON_LENGTH('{"a":"b"}','$','$', 'foo');
+ERROR 42000: Incorrect parameter count in the call to native function 'json_length'
+SELECT JSON_LENGTH();
+ERROR 42000: Incorrect parameter count in the call to native function 'JSON_LENGTH'
+#
 # End of 10.4 tests
 #

mysql-test/main/func_json.test

@@ -665,6 +665,7 @@ SELECT 1 + JSON_VALUE('{"nulltest": null}', '$.nulltest');
 SELECT NULL;
 SELECT JSON_EXTRACT('{"a":null, "b":10, "c":"null"}', '$.a');
 
+
 --echo #
 --echo # End of 10.3 tests
 --echo #
@@ -816,6 +817,14 @@ select JSON_PRETTY(JSON_EXTRACT(a, '$**.analyzing_range_alternatives')) from t20
 select JSON_LOOSE(JSON_EXTRACT(a, '$**.analyzing_range_alternatives')) from t200;
 drop table t200;
 
+--echo #
+--echo # MDEV-24538: JSON_LENGTH does not return error upon wrong number of parameters
+--echo #
+--error ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT
+SELECT JSON_LENGTH('{"a":"b"}','$','$', 'foo');
+--error ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT
+SELECT JSON_LENGTH();
+
 --echo #
 --echo # End of 10.4 tests
 --echo #

sql/item_jsonfunc.h

@@ -310,6 +310,11 @@ class Item_func_json_length: public Item_long_func
 {
   bool check_arguments() const
   {
+    if (arg_count == 0 || arg_count > 2)
+    {
+      my_error(ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT, MYF(0), func_name());
+      return true;
+    }
     return args[0]->check_type_can_return_text(func_name()) ||
            (arg_count > 1 &&
             args[1]->check_type_general_purpose_string(func_name()));