Bug#25516960: JSON_SEARCH AND JSON_CONTAINS_PATH REJECT ONE-OR-ALL

              ARGUMENT IF IT IS UTF-16

Problem: The one-or-all argument is assumed to be utf8mb4 and is
always believed to be different from "one" or "all" when it is encoded
in UTF-16.

Fix: Convert the one-or-all argument to utf8mb4 before checking if it
is "one" or "all".

Change-Id: Ic2160d1928d9afe8dcdc57aae72bb18958540946

Author: kahatlen

mysql-test/suite/json/r/json_no_table.result

@@ -3320,3 +3320,15 @@ SELECT HEX(JSON_UNQUOTE(CAST('"abc"' AS CHAR CHARSET utf16))),
 HEX(JSON_UNQUOTE(CAST('abc' AS CHAR CHARSET utf16)));
 HEX(JSON_UNQUOTE(CAST('"abc"' AS CHAR CHARSET utf16)))	HEX(JSON_UNQUOTE(CAST('abc' AS CHAR CHARSET utf16)))
 616263	616263
+#
+# Bug#25516960: JSON_SEARCH AND JSON_CONTAINS_PATH REJECT ONE-OR-ALL
+#               ARGUMENT IF IT IS UTF-16
+#
+SELECT JSON_SEARCH('["a", "a"]', CAST('one' AS CHAR CHARSET utf16), 'a') AS c1,
+JSON_SEARCH('["a", "a"]', CAST('all' AS CHAR CHARSET utf16), 'a') AS c2,
+JSON_CONTAINS_PATH('{"a":"x"}', CAST('one' AS CHAR CHARSET utf16),
+'$.a', '$.b') AS c3,
+JSON_CONTAINS_PATH('{"a":"x"}', CAST('all' AS CHAR CHARSET utf16),
+'$.a', '$.b') AS c4;
+c1	c2	c3	c4
+"$[0]"	["$[0]", "$[1]"]	1	0

mysql-test/suite/json/t/json_no_table.test

@@ -2318,3 +2318,14 @@ SELECT JSON_UNQUOTE(CAST('ABCD' AS BINARY));
 # JSON_UNQUOTE should return utf8mb4 encoded results, but used to return utf16.
 SELECT HEX(JSON_UNQUOTE(CAST('"abc"' AS CHAR CHARSET utf16))),
        HEX(JSON_UNQUOTE(CAST('abc' AS CHAR CHARSET utf16)));
+
+--echo #
+--echo # Bug#25516960: JSON_SEARCH AND JSON_CONTAINS_PATH REJECT ONE-OR-ALL
+--echo #               ARGUMENT IF IT IS UTF-16
+--echo #
+SELECT JSON_SEARCH('["a", "a"]', CAST('one' AS CHAR CHARSET utf16), 'a') AS c1,
+       JSON_SEARCH('["a", "a"]', CAST('all' AS CHAR CHARSET utf16), 'a') AS c2,
+       JSON_CONTAINS_PATH('{"a":"x"}', CAST('one' AS CHAR CHARSET utf16),
+                          '$.a', '$.b') AS c3,
+       JSON_CONTAINS_PATH('{"a":"x"}', CAST('all' AS CHAR CHARSET utf16),
+                          '$.a', '$.b') AS c4;

sql/item_json_func.cc

@@ -391,13 +391,31 @@ static bool parse_path(Item * path_expression, String *value,
 
   @returns ooa_one, ooa_all, or ooa_error, based on the match
 */
-static enum_one_or_all_type parse_one_or_all(const char *candidate,
+static enum_one_or_all_type parse_one_or_all(const String *candidate,
                                              const char *func_name)
 {
-  if (!my_strcasecmp(&my_charset_utf8mb4_general_ci, candidate, "all"))
+  /*
+    First convert the candidate to utf8mb4.
+
+    A buffer of four bytes is enough to hold the candidate in the common
+    case ("one" or "all" + terminating NUL character).
+
+    We can ignore conversion errors here. If a conversion error should
+    happen, the converted string will contain a question mark, and we will
+    correctly raise an error later because no string with a question mark
+    will match "one" or "all".
+  */
+  StringBuffer<4> utf8str;
+  uint errors;
+  if (utf8str.copy(candidate->ptr(), candidate->length(), candidate->charset(),
+                   &my_charset_utf8mb4_bin, &errors))
+    return ooa_error;                           /* purecov: inspected */
+
+  const char *str= utf8str.c_ptr_safe();
+  if (!my_strcasecmp(&my_charset_utf8mb4_general_ci, str, "all"))
     return ooa_all;
 
-  if (!my_strcasecmp(&my_charset_utf8mb4_general_ci, candidate, "one"))
+  if (!my_strcasecmp(&my_charset_utf8mb4_general_ci, str, "one"))
     return ooa_one;
 
   my_error(ER_JSON_BAD_ONE_OR_ALL_ARG, MYF(0), func_name);
@@ -436,7 +454,7 @@ static enum_one_or_all_type parse_and_cache_ooa(Item *arg,
   }
   else
   {
-    *cached_ooa= parse_one_or_all(one_or_all->c_ptr_safe(), func_name);
+    *cached_ooa= parse_one_or_all(one_or_all, func_name);
   }
 
   return *cached_ooa;