From 70f4332beac65359d23733cc179c5c3cc689ef95 Mon Sep 17 00:00:00 2001
From: casazhang <casazhang@tencent.com>
Date: Mon, 19 Sep 2022 19:11:28 +0800
Subject: [PATCH] [bugfix] gtid_subset should reset null_value to false.

gtid_subset should reset null_value to false, otherwise
records will be lost when scanning multiple records.
---
 mysql-test/suite/json/inc/json_functions.inc   | 14 ++++++++++++++
 .../suite/json/r/json_functions_innodb.result  | 13 +++++++++++++
 sql/item_func.cc                               | 18 ++++++++----------
 3 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/mysql-test/suite/json/inc/json_functions.inc b/mysql-test/suite/json/inc/json_functions.inc
index c0cec7b5fe3..2914835ea98 100644
--- a/mysql-test/suite/json/inc/json_functions.inc
+++ b/mysql-test/suite/json/inc/json_functions.inc
@@ -757,6 +757,20 @@ select json_extract(en, '$') from t1;
 
 drop table t1;
 
+create table t1 ( c1 int, c2 text);
+
+insert into t1 values (1, '{\"time\":\"2022-09-18 17:18:12\"}');
+insert into t1 values (2, '{\"time\":\"2022-09-19 17:18:12\", \"gtid_set_column\":\"c55be2ea-14fc-12ec-a970-043f72e646cf:1-6667608119\"}');
+insert into t1 values (3, '{\"time\":\"2022-09-20 17:18:12\"}');
+insert into t1 values (4, '{\"time\":\"2022-09-21 17:18:12\", \"gtid_set_column\":\"c55be2ea-14fc-12ec-a970-043f72e646cf:1-6667608114\"}');
+insert into t1 values (5, '{\"time\":\"2022-09-22 17:18:12\"}');
+insert into t1 values (6, '{\"time\":\"2022-09-23 17:18:12\", \"gtid_set_column\":\"03465097-563b-12ec-a4cb-0c42a14d69f3:1-234648230\"}');
+insert into t1 values (7, '{\"time\":\"2022-09-24 17:18:12\"}');
+
+select t1.c1 from t1 where gtid_subset(trim('"' from json_extract(t1.c2, '$.gtid_set_column')), "03465097-563b-12ec-a4cb-0c42a14d69f3:1-234648290") = 0;
+
+drop table t1;
+
 create table t1 ( c1 varchar(200) character set 'latin1',
                   c2 varchar(200) character set 'utf8' );
 insert into t1 values ('[1,2]',  # legal json, but not utf-8
diff --git a/mysql-test/suite/json/r/json_functions_innodb.result b/mysql-test/suite/json/r/json_functions_innodb.result
index c2fa1dd9ede..36a81bd4b5b 100644
--- a/mysql-test/suite/json/r/json_functions_innodb.result
+++ b/mysql-test/suite/json/r/json_functions_innodb.result
@@ -5023,6 +5023,19 @@ cast(js as json)
 select json_extract(en, '$') from t1;
 ERROR 22032: Invalid data type for JSON data in argument 1 to function json_extract; a JSON string or JSON type is required.
 drop table t1;
+create table t1 ( c1 int, c2 text);
+insert into t1 values (1, '{\"time\":\"2022-09-18 17:18:12\"}');
+insert into t1 values (2, '{\"time\":\"2022-09-19 17:18:12\", \"gtid_set_column\":\"c55be2ea-14fc-12ec-a970-043f72e646cf:1-6667608119\"}');
+insert into t1 values (3, '{\"time\":\"2022-09-20 17:18:12\"}');
+insert into t1 values (4, '{\"time\":\"2022-09-21 17:18:12\", \"gtid_set_column\":\"c55be2ea-14fc-12ec-a970-043f72e646cf:1-6667608114\"}');
+insert into t1 values (5, '{\"time\":\"2022-09-22 17:18:12\"}');
+insert into t1 values (6, '{\"time\":\"2022-09-23 17:18:12\", \"gtid_set_column\":\"03465097-563b-12ec-a4cb-0c42a14d69f3:1-234648230\"}');
+insert into t1 values (7, '{\"time\":\"2022-09-24 17:18:12\"}');
+select t1.c1 from t1 where gtid_subset(trim('"' from json_extract(t1.c2, '$.gtid_set_column')), "03465097-563b-12ec-a4cb-0c42a14d69f3:1-234648290") = 0;
+c1
+2
+4
+drop table t1;
 create table t1 ( c1 varchar(200) character set 'latin1',
 c2 varchar(200) character set 'utf8' );
 insert into t1 values ('[1,2]',  # legal json, but not utf-8
diff --git a/sql/item_func.cc b/sql/item_func.cc
index db8d2c15ab8..044a47e6884 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -5167,21 +5167,19 @@ longlong Item_master_gtid_set_wait::val_int()
 longlong Item_func_gtid_subset::val_int()
 {
   DBUG_ENTER("Item_func_gtid_subset::val_int()");
-  if (args[0]->null_value || args[1]->null_value)
-  {
-    null_value= true;
-    DBUG_RETURN(0);
-  }
   String *string1, *string2;
   const char *charp1, *charp2;
   int ret= 1;
   enum_return_status status;
-  // get strings without lock
-  if ((string1= args[0]->val_str(&buf1)) != NULL &&
-      (charp1= string1->c_ptr_safe()) != NULL &&
-      (string2= args[1]->val_str(&buf2)) != NULL &&
-      (charp2= string2->c_ptr_safe()) != NULL)
+  null_value= false;
+  if ((string1 = args[0]->val_str(&buf1)) == NULL ||
+      (string2 = args[1]->val_str(&buf2)) == NULL)
   {
+    null_value = true;
+    ret = 0;
+  } else if ((charp1= string1->c_ptr_safe()) != NULL &&
+      (charp2= string2->c_ptr_safe()) != NULL)
+  { // get strings without lock
     Sid_map sid_map(NULL/*no rwlock*/);
     // compute sets while holding locks
     const Gtid_set sub_set(&sid_map, charp1, &status);
-- 
2.26.2