MDEV-18119 upgrading from 10.3 to 10.4 can result in the password for a user to be wiped ou

mysql-test/main/mysql_upgrade.result

@@ -316,7 +316,7 @@ Grants for user3@%
 GRANT USAGE ON *.* TO 'user3'@'%'
 GRANT ALL PRIVILEGES ON `roelt`.`test2` TO 'user3'@'%'
 DROP USER 'user3'@'%';
-End of 5.1 tests
+# End of 5.1 tests
 The --upgrade-system-tables option was used, user tables won't be touched.
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
@@ -505,7 +505,7 @@ length(table_name)
 79
 79
 drop table extralongname_extralongname_extralongname_extralongname_ext;
-End of 10.0 tests
+# End of 10.0 tests
 set sql_mode=default;
 # Droping the previously created mysql_upgrade_info file..
 create table test.t1(a int) engine=MyISAM;
@@ -569,8 +569,8 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 DROP TABLE test.t1;
 SET GLOBAL enforce_storage_engine=NULL;
-End of 10.1 tests
-Start of 10.3 tests
+# End of 10.1 tests
+# End of 10.2 tests
 #
 # Ensure that mysql_upgrade correctly sets truncate_versioning_priv
 # on upgrade from 10.2
@@ -591,3 +591,36 @@ DROP USER 'user3'@'%';
 update mysql.db set Delete_history_priv='Y' where db like 'test%';
 drop table mysql.global_priv;
 rename table mysql.global_priv_bak to mysql.global_priv;
+# End of 10.3 tests
+drop view mysql.user_bak;
+create user 'user3'@'localhost' identified with mysql_native_password as password('a_password');
+show create user user3@localhost;
+CREATE USER for user3@localhost
+CREATE USER 'user3'@'localhost' IDENTIFIED BY PASSWORD '*5DC1D11F45824A9DD613961F05C1EC1E7A1601AA'
+update mysql.user set password=authentication_string, authentication_string='' where user='user3';
+select password,plugin,authentication_string from mysql.user where user='user3';
+password	plugin	authentication_string
+*5DC1D11F45824A9DD613961F05C1EC1E7A1601AA	mysql_native_password	
+flush privileges;
+show create user user3@localhost;
+CREATE USER for user3@localhost
+CREATE USER 'user3'@'localhost' IDENTIFIED BY PASSWORD '*5DC1D11F45824A9DD613961F05C1EC1E7A1601AA'
+connect con1,localhost,user3,a_password;
+select current_user();
+current_user()
+user3@localhost
+disconnect con1;
+connection default;
+# mysql_upgrade --force --silent 2>&1
+show create user user3@localhost;
+CREATE USER for user3@localhost
+CREATE USER 'user3'@'localhost' IDENTIFIED BY PASSWORD '*5DC1D11F45824A9DD613961F05C1EC1E7A1601AA'
+connect con1,localhost,user3,a_password;
+select current_user();
+current_user()
+user3@localhost
+disconnect con1;
+connection default;
+drop user user3@localhost;
+drop table mysql.global_priv;
+rename table mysql.global_priv_bak to mysql.global_priv;

mysql-test/main/mysql_upgrade.test

@@ -106,8 +106,7 @@ SHOW GRANTS FOR 'user3'@'%';
 
 DROP USER 'user3'@'%';
 
---echo End of 5.1 tests
-
+--echo # End of 5.1 tests
 
 #
 # Test the --upgrade-system-tables option
@@ -192,7 +191,7 @@ create table extralongname_extralongname_extralongname_extralongname_ext (
 select length(table_name) from mysql.innodb_table_stats;
 drop table extralongname_extralongname_extralongname_extralongname_ext;
 
---echo End of 10.0 tests
+--echo # End of 10.0 tests
 
 set sql_mode=default;
 
@@ -218,9 +217,9 @@ DROP TABLE test.t1;
 --remove_file $MYSQLD_DATADIR/mysql_upgrade_info
 SET GLOBAL enforce_storage_engine=NULL;
 
---echo End of 10.1 tests
+--echo # End of 10.1 tests
 
---echo Start of 10.3 tests
+--echo # End of 10.2 tests
 
 --echo #
 --echo # Ensure that mysql_upgrade correctly sets truncate_versioning_priv
@@ -244,3 +243,29 @@ DROP USER 'user3'@'%';
 update mysql.db set Delete_history_priv='Y' where db like 'test%';
 drop table mysql.global_priv;
 rename table mysql.global_priv_bak to mysql.global_priv;
+
+--echo # End of 10.3 tests
+
+--source include/switch_to_mysql_user.inc
+drop view mysql.user_bak;
+create user 'user3'@'localhost' identified with mysql_native_password as password('a_password');
+show create user user3@localhost;
+update mysql.user set password=authentication_string, authentication_string='' where user='user3';
+select password,plugin,authentication_string from mysql.user where user='user3';
+flush privileges;
+show create user user3@localhost;
+connect con1,localhost,user3,a_password;
+select current_user();
+disconnect con1;
+connection default;
+--echo # mysql_upgrade --force --silent 2>&1
+--exec $MYSQL_UPGRADE --force --silent 2>&1
+--remove_file $MYSQLD_DATADIR/mysql_upgrade_info
+show create user user3@localhost;
+connect con1,localhost,user3,a_password;
+select current_user();
+disconnect con1;
+connection default;
+drop user user3@localhost;
+drop table mysql.global_priv;
+rename table mysql.global_priv_bak to mysql.global_priv;

scripts/mysql_system_tables_fix.sql

@@ -803,7 +803,7 @@ IF 'BASE TABLE' = (select table_type from information_schema.tables where table_
                     'max_user_connections', max_user_connections,
                     'max_statement_time', max_statement_time,
                     'plugin', if(plugin>'',plugin,if(length(password)=16,'mysql_old_password','mysql_native_password')),
-                    'authentication_string', if(plugin>'',authentication_string,password),
+                    'authentication_string', if(plugin>'' and authentication_string>'',authentication_string,password),
                     'default_role', default_role,
                     'is_role', 'Y'=is_role)) as Priv
   FROM user;