MDEV-11856 json_search doesn't search for values with double quotes

character (").

        The my_wildcmp function doesn't expect the string parameter to
        have escapements, only the template. So the string
        should be unescaped if necessary.

Author: Alexey Botchkov

include/json_lib.h

@@ -203,6 +203,7 @@ typedef struct st_json_engine_t
   enum json_value_types value_type; /* type of the value.*/
   const uchar *value;      /* Points to the value. */
   const uchar *value_begin;/* Points to where the value starts in the JSON. */
+  int value_escaped;       /* Flag telling if the string value has escaping.*/
   uint num_flags;  /* the details of the JSON_VALUE_NUMBER, is it negative,
                       or if it has the fractional part.
                       See the enum json_num_flags. */

mysql-test/r/func_json.result

@@ -589,3 +589,9 @@ json_detailed('{"a":1, "b":[1,2,3], "c":{"aa":"v1", "bb": "v2"}}')
         "bb": "v2"
     }
 }
+SELECT JSON_search( '{"x": "\\""}', "one", '"');
+JSON_search( '{"x": "\\""}', "one", '"')
+"$.x"
+SELECT JSON_search( '{"x": "\\""}', "one", '\\"');
+JSON_search( '{"x": "\\""}', "one", '\\"')
+"$.x"

mysql-test/t/func_json.test

@@ -238,3 +238,10 @@ select json_merge('{"a":{"u":12, "x":"b", "r":1}}', '{"a":{"x":"c", "r":2}}') ;
 select json_compact('{"a":1, "b":[1,2,3], "c":{"aa":"v1", "bb": "v2"}}');
 select json_loose('{"a":1, "b":[1,2,3], "c":{"aa":"v1", "bb": "v2"}}');
 select json_detailed('{"a":1, "b":[1,2,3], "c":{"aa":"v1", "bb": "v2"}}');
+
+#
+# MDEV-11856 json_search doesn't search for values with double quotes character (")
+#
+
+SELECT JSON_search( '{"x": "\\""}', "one", '"');
+SELECT JSON_search( '{"x": "\\""}', "one", '\\"');

sql/item_jsonfunc.cc

@@ -2800,9 +2800,28 @@ void Item_func_json_search::fix_length_and_dec()
 int Item_func_json_search::compare_json_value_wild(json_engine_t *je,
                                                    const String *cmp_str)
 {
-  return my_wildcmp(collation.collation,
-      (const char *) je->value, (const char *) (je->value + je->value_len),
-      cmp_str->ptr(), cmp_str->end(), escape, wild_one, wild_many) ? 0 : 1;
+  if (je->value_type != JSON_VALUE_STRING || !je->value_escaped)
+    return my_wildcmp(collation.collation,
+        (const char *) je->value, (const char *) (je->value + je->value_len),
+        cmp_str->ptr(), cmp_str->end(), escape, wild_one, wild_many) ? 0 : 1;
+
+  {
+    int esc_len;
+    if (esc_value.alloced_length() < (uint) je->value_len &&
+        esc_value.alloc((je->value_len / 1024 + 1) * 1024))
+      return 0;
+
+    esc_len= json_unescape(je->s.cs, je->value, je->value + je->value_len,
+                           je->s.cs, (uchar *) esc_value.ptr(),
+                           (uchar *) (esc_value.ptr() + 
+                                      esc_value.alloced_length()));
+    if (esc_len <= 0)
+      return 0;
+
+    return my_wildcmp(collation.collation,
+        esc_value.ptr(), esc_value.ptr() + esc_len,
+        cmp_str->ptr(), cmp_str->end(), escape, wild_one, wild_many) ? 0 : 1;
+  }
 }
 
 

sql/item_jsonfunc.h

@@ -392,7 +392,7 @@ class Item_func_json_keys: public Item_str_func
 class Item_func_json_search: public Item_json_str_multipath
 {
 protected:
-  String tmp_js;
+  String tmp_js, esc_value;
   bool mode_one;
   bool ooa_constant, ooa_parsed;
   int escape;

strings/json_lib.c

@@ -366,6 +366,7 @@ static int skip_str_constant(json_engine_t *j)
         break;
       if (j->s.c_next == '\\')
       {
+        j->value_escaped= 1;
         if (json_handle_esc(&j->s))
           return 1;
         continue;
@@ -394,6 +395,7 @@ static int read_strn(json_engine_t *j)
 {
   j->value= j->s.c_str;
   j->value_type= JSON_VALUE_STRING;
+  j->value_escaped= 0;
 
   if (skip_str_constant(j))
     return 1;