MDEV-17018 JSON_SEARCH and User-Defined Variables.

Item_func_json_search needs a member to store the path.

mysql-test/r/func_json.result

@@ -796,3 +796,11 @@ JSON_SET('{}', '$.a', _utf8 X'C3B6', '$.x', 1, '$.b', _utf8 X'C3B6')
 select json_array_append('[             ]', '$', 'aue');
 json_array_append('[             ]', '$', 'aue')
 ["aue"]
+#
+# MDEV-17018 JSON_SEARCH and User-Defined Variables.
+#
+SET @`json` := '["A", [{"B": "1"}], {"C": "AB"}, {"D": "BC"}]', @`value` := 'AB';
+SELECT JSON_SEARCH(@`json`, 'one', @`value`);
+JSON_SEARCH(@`json`, 'one', @`value`)
+"$[2].C"
+SET @`json` := NULL, @`value` := NULL;

mysql-test/t/func_json.test

@@ -455,3 +455,11 @@ SELECT JSON_SET('{}', '$.a', _utf8 X'C3B6', '$.x', 1, '$.b', _utf8 X'C3B6');
 
 select json_array_append('[             ]', '$', 'aue');
 
+--echo #
+--echo # MDEV-17018 JSON_SEARCH and User-Defined Variables.
+--echo #
+
+SET @`json` := '["A", [{"B": "1"}], {"C": "AB"}, {"D": "BC"}]', @`value` := 'AB';
+SELECT JSON_SEARCH(@`json`, 'one', @`value`);
+SET @`json` := NULL, @`value` := NULL;
+

sql/item_jsonfunc.cc

@@ -3056,7 +3056,7 @@ static int append_json_path(String *str, const json_path_t *p)
 String *Item_func_json_search::val_str(String *str)
 {
   String *js= args[0]->val_json(&tmp_js);
-  String *s_str= args[2]->val_str(&tmp_js);
+  String *s_str= args[2]->val_str(&tmp_path);
   json_engine_t je;
   json_path_t p, sav_path;
   uint n_arg;

sql/item_jsonfunc.h

@@ -400,7 +400,7 @@ class Item_func_json_keys: public Item_str_func
 class Item_func_json_search: public Item_json_str_multipath
 {
 protected:
-  String tmp_js, esc_value;
+  String tmp_js, tmp_path, esc_value;
   bool mode_one;
   bool ooa_constant, ooa_parsed;
   int escape;