Fixes for mysql-test failures

mysql-test/r/acl_roles_show_grants.result:
  one can do SHOW GRANTS for himself
mysql-test/t/acl_roles_set_role-table-column-priv.test:
  correct error message
mysql-test/t/acl_roles_show_grants.test:
  one can SHOW GRANTS for himself
sql/sql_acl.cc:
  bugfixing:
  * don't assign with && - it can shortcut and the second assignment won't be executed
  * correct the test in check_grant_all_columns() - want_access should not be modified
  *
sql/sql_cmd.h.OTHER:
  add new commands at the end
sql/sql_db.cc:
  don't call acl_get() if all privileges are already satisfied
  (crashes when run with --skip-grants, because acl data stuctures aren't initialized)
sql/sql_parse.cc:
  * test for current_user in get_current_user()
  * map explicitly specified user@host to current_user

28 files changed, 145 insertions, 50 deletions

diff --git a/mysql-test/r/acl_roles_set_role-table-column-priv.result b/mysql-test/r/acl_roles_set_role-table-column-priv.result
index bbb964b5d20..4f02b3ec246 100644
--- a/mysql-test/r/acl_roles_set_role-table-column-priv.result
+++ b/mysql-test/r/acl_roles_set_role-table-column-priv.result
@@ -40,7 +40,7 @@ GRANT USAGE ON *.* TO 'test_user'@'localhost'
 GRANT test_role1 TO 'test_user'@'localhost'
 GRANT test_role2 TO 'test_role1'
 select * from mysql.roles_mapping;
-ERROR 42000:  command denied to user 'test_user'@'localhost' for table 'roles_mapping'
+ERROR 42000: SELECT command denied to user 'test_user'@'localhost' for column 'HostFk' in table 'roles_mapping'
 select RoleFk from mysql.roles_mapping;
 RoleFk
 test_role1
diff --git a/mysql-test/r/acl_roles_show_grants.result b/mysql-test/r/acl_roles_show_grants.result
index a28330379b5..7ac434385a7 100644
--- a/mysql-test/r/acl_roles_show_grants.result
+++ b/mysql-test/r/acl_roles_show_grants.result
@@ -60,7 +60,10 @@ GRANT USAGE ON *.* TO 'test_user'@'localhost'
 GRANT test_role1 TO 'test_user'@'localhost'
 GRANT test_role2 TO 'test_user'@'localhost'
 show grants for test_user@localhost;
-ERROR 42000: Access denied for user 'test_user'@'localhost' to database 'mysql'
+Grants for test_user@localhost
+GRANT test_role2 TO 'test_user'@'localhost'
+GRANT test_role1 TO 'test_user'@'localhost'
+GRANT USAGE ON *.* TO 'test_user'@'localhost'
 show grants for test_role1;
 ERROR 42000: Access denied for user 'test_user'@'localhost' to database 'mysql'
 show grants for test_role2;
diff --git a/mysql-test/r/connect.result b/mysql-test/r/connect.result
index b90e558cfaa..1ac1f89eeac 100644
--- a/mysql-test/r/connect.result
+++ b/mysql-test/r/connect.result
@@ -19,6 +19,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
@@ -57,6 +58,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
@@ -103,6 +105,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
diff --git a/mysql-test/r/grant.result b/mysql-test/r/grant.result
index f3910b67dd3..bf67bb5dd6f 100644
--- a/mysql-test/r/grant.result
+++ b/mysql-test/r/grant.result
@@ -55,6 +55,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 show grants for mysqltest_1@localhost;
 Grants for mysqltest_1@localhost
 GRANT USAGE ON *.* TO 'mysqltest_1'@'localhost' REQUIRE CIPHER 'EDH-RSA-DES-CBC3-SHA'
@@ -126,6 +127,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 show grants for mysqltest_1@localhost;
 Grants for mysqltest_1@localhost
 GRANT USAGE ON *.* TO 'mysqltest_1'@'localhost' WITH MAX_QUERIES_PER_HOUR 10
@@ -173,6 +175,7 @@ max_connections	30
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 show grants for mysqltest_1@localhost;
 Grants for mysqltest_1@localhost
 GRANT USAGE ON *.* TO 'mysqltest_1'@'localhost' WITH MAX_QUERIES_PER_HOUR 10 MAX_UPDATES_PER_HOUR 20 MAX_CONNECTIONS_PER_HOUR 30
diff --git a/mysql-test/r/information_schema.result b/mysql-test/r/information_schema.result
index bf25b1c28ee..eabae78a5f2 100644
--- a/mysql-test/r/information_schema.result
+++ b/mysql-test/r/information_schema.result
@@ -99,6 +99,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 t1
@@ -706,6 +707,7 @@ max_questions	select,insert,update,references
 max_connections	select,insert,update,references
 max_user_connections	select,insert,update,references
 authentication_string	select,insert,update,references
+is_role	select,insert,update,references
 use test;
 create function sub1(i int) returns int
 return i+1;
diff --git a/mysql-test/r/information_schema_all_engines.result b/mysql-test/r/information_schema_all_engines.result
index 3e95d9892cb..62f3ee85530 100644
--- a/mysql-test/r/information_schema_all_engines.result
+++ b/mysql-test/r/information_schema_all_engines.result
@@ -424,4 +424,4 @@ Wildcard: inf_rmation_schema
 SELECT table_schema, count(*) FROM information_schema.TABLES WHERE table_schema IN ('mysql', 'INFORMATION_SCHEMA', 'test', 'mysqltest') AND table_name<>'ndb_binlog_index' AND table_name<>'ndb_apply_status' GROUP BY TABLE_SCHEMA;
 table_schema	count(*)
 information_schema	59
-mysql	27
+mysql	28
diff --git a/mysql-test/r/log_tables_upgrade.result b/mysql-test/r/log_tables_upgrade.result
index abae156ac5e..bae329073a7 100644
--- a/mysql-test/r/log_tables_upgrade.result
+++ b/mysql-test/r/log_tables_upgrade.result
@@ -37,6 +37,7 @@ mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
 mysql.renamed_general_log                          OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
diff --git a/mysql-test/r/mysql_upgrade.result b/mysql-test/r/mysql_upgrade.result
index be51cf8ca11..e1c7e78de92 100644
--- a/mysql-test/r/mysql_upgrade.result
+++ b/mysql-test/r/mysql_upgrade.result
@@ -24,6 +24,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -65,6 +66,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -106,6 +108,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -149,6 +152,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -196,6 +200,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -246,6 +251,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -299,6 +305,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
diff --git a/mysql-test/r/mysql_upgrade_ssl.result b/mysql-test/r/mysql_upgrade_ssl.result
index 3b84664708c..c8c4252c5c2 100644
--- a/mysql-test/r/mysql_upgrade_ssl.result
+++ b/mysql-test/r/mysql_upgrade_ssl.result
@@ -26,6 +26,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
diff --git a/mysql-test/r/mysqlcheck.result b/mysql-test/r/mysqlcheck.result
index b25a9be8872..3f5c08d7294 100644
--- a/mysql-test/r/mysqlcheck.result
+++ b/mysql-test/r/mysqlcheck.result
@@ -20,6 +20,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -48,6 +49,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -74,6 +76,7 @@ mysql.plugin                                       OK
 mysql.proc                                         OK
 mysql.procs_priv                                   OK
 mysql.proxies_priv                                 OK
+mysql.roles_mapping                                OK
 mysql.servers                                      OK
 mysql.table_stats                                  OK
 mysql.tables_priv                                  OK
@@ -100,6 +103,7 @@ mysql.plugin                                       Table is already up to date
 mysql.proc                                         Table is already up to date
 mysql.procs_priv                                   Table is already up to date
 mysql.proxies_priv                                 Table is already up to date
+mysql.roles_mapping                                Table is already up to date
 mysql.servers                                      Table is already up to date
 mysql.table_stats                                  Table is already up to date
 mysql.tables_priv                                  Table is already up to date
diff --git a/mysql-test/r/ps.result b/mysql-test/r/ps.result
index 95217d9716a..4f41151f555 100644
--- a/mysql-test/r/ps.result
+++ b/mysql-test/r/ps.result
@@ -1201,13 +1201,13 @@ SET @aux= "SELECT COUNT(*)
 prepare my_stmt from @aux;
 execute my_stmt;
 COUNT(*)
-42
+43
 execute my_stmt;
 COUNT(*)
-42
+43
 execute my_stmt;
 COUNT(*)
-42
+43
 deallocate prepare my_stmt;
 drop procedure if exists p1|
 drop table if exists t1|
diff --git a/mysql-test/r/system_mysql_db.result b/mysql-test/r/system_mysql_db.result
index a92decefbc8..47d831af115 100644
--- a/mysql-test/r/system_mysql_db.result
+++ b/mysql-test/r/system_mysql_db.result
@@ -18,6 +18,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
@@ -126,6 +127,7 @@ user	CREATE TABLE `user` (
   `max_user_connections` int(11) NOT NULL DEFAULT '0',
   `plugin` char(64) CHARACTER SET latin1 NOT NULL DEFAULT '',
   `authentication_string` text COLLATE utf8_bin NOT NULL,
+  `is_role` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
   PRIMARY KEY (`Host`,`User`)
 ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Users and global privileges'
 show create table func;
diff --git a/mysql-test/r/system_mysql_db_fix40123.result b/mysql-test/r/system_mysql_db_fix40123.result
index 04b20c42af3..052e2966f70 100644
--- a/mysql-test/r/system_mysql_db_fix40123.result
+++ b/mysql-test/r/system_mysql_db_fix40123.result
@@ -18,6 +18,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
@@ -124,6 +125,7 @@ user	CREATE TABLE `user` (
   `max_updates` int(11) unsigned NOT NULL DEFAULT '0',
   `max_connections` int(11) unsigned NOT NULL DEFAULT '0',
   `max_user_connections` int(11) NOT NULL DEFAULT '0',
+  `is_role` enum('N','Y') COLLATE utf8_bin NOT NULL DEFAULT 'N',
   `plugin` char(64) CHARACTER SET latin1 NOT NULL DEFAULT '',
   `authentication_string` text COLLATE utf8_bin NOT NULL,
   PRIMARY KEY (`Host`,`User`)
diff --git a/mysql-test/r/system_mysql_db_fix50030.result b/mysql-test/r/system_mysql_db_fix50030.result
index 04b20c42af3..052e2966f70 100644
--- a/mysql-test/r/system_mysql_db_fix50030.result
+++ b/mysql-test/r/system_mysql_db_fix50030.result
@@ -18,6 +18,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
@@ -124,6 +125,7 @@ user	CREATE TABLE `user` (
   `max_updates` int(11) unsigned NOT NULL DEFAULT '0',
   `max_connections` int(11) unsigned NOT NULL DEFAULT '0',
   `max_user_connections` int(11) NOT NULL DEFAULT '0',
+  `is_role` enum('N','Y') COLLATE utf8_bin NOT NULL DEFAULT 'N',
   `plugin` char(64) CHARACTER SET latin1 NOT NULL DEFAULT '',
   `authentication_string` text COLLATE utf8_bin NOT NULL,
   PRIMARY KEY (`Host`,`User`)
diff --git a/mysql-test/r/system_mysql_db_fix50117.result b/mysql-test/r/system_mysql_db_fix50117.result
index 04b20c42af3..052e2966f70 100644
--- a/mysql-test/r/system_mysql_db_fix50117.result
+++ b/mysql-test/r/system_mysql_db_fix50117.result
@@ -18,6 +18,7 @@ plugin
 proc
 procs_priv
 proxies_priv
+roles_mapping
 servers
 slow_log
 table_stats
@@ -124,6 +125,7 @@ user	CREATE TABLE `user` (
   `max_updates` int(11) unsigned NOT NULL DEFAULT '0',
   `max_connections` int(11) unsigned NOT NULL DEFAULT '0',
   `max_user_connections` int(11) NOT NULL DEFAULT '0',
+  `is_role` enum('N','Y') COLLATE utf8_bin NOT NULL DEFAULT 'N',
   `plugin` char(64) CHARACTER SET latin1 NOT NULL DEFAULT '',
   `authentication_string` text COLLATE utf8_bin NOT NULL,
   PRIMARY KEY (`Host`,`User`)
diff --git a/mysql-test/suite/funcs_1/r/is_columns_mysql.result b/mysql-test/suite/funcs_1/r/is_columns_mysql.result
index 3e128da635d..f9d414e1433 100644
--- a/mysql-test/suite/funcs_1/r/is_columns_mysql.result
+++ b/mysql-test/suite/funcs_1/r/is_columns_mysql.result
@@ -161,6 +161,9 @@ def	mysql	proxies_priv	Proxied_user	4		NO	char	16	48	NULL	NULL	NULL	utf8	utf8_bi
 def	mysql	proxies_priv	Timestamp	7	CURRENT_TIMESTAMP	NO	timestamp	NULL	NULL	NULL	NULL	0	NULL	NULL	timestamp		on update CURRENT_TIMESTAMP	select,insert,update,references	
 def	mysql	proxies_priv	User	2		NO	char	16	48	NULL	NULL	NULL	utf8	utf8_bin	char(16)	PRI		select,insert,update,references	
 def	mysql	proxies_priv	With_grant	5	0	NO	tinyint	NULL	NULL	3	0	NULL	NULL	NULL	tinyint(1)			select,insert,update,references	
+def	mysql	roles_mapping	HostFk	1		NO	char	60	60	NULL	NULL	NULL	latin1	latin1_bin	char(60)			select,insert,update,references	
+def	mysql	roles_mapping	RoleFk	3		NO	char	16	16	NULL	NULL	NULL	latin1	latin1_bin	char(16)			select,insert,update,references	
+def	mysql	roles_mapping	UserFk	2		NO	char	16	16	NULL	NULL	NULL	latin1	latin1_bin	char(16)			select,insert,update,references	
 def	mysql	servers	Db	3		NO	char	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	char(64)			select,insert,update,references	
 def	mysql	servers	Host	2		NO	char	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	char(64)			select,insert,update,references	
 def	mysql	servers	Owner	9		NO	char	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	char(64)			select,insert,update,references	
@@ -224,6 +227,7 @@ def	mysql	user	Grant_priv	14	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_general_ci	e
 def	mysql	user	Host	1		NO	char	60	180	NULL	NULL	NULL	utf8	utf8_bin	char(60)	PRI		select,insert,update,references	
 def	mysql	user	Index_priv	16	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_general_ci	enum('N','Y')			select,insert,update,references	
 def	mysql	user	Insert_priv	5	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_general_ci	enum('N','Y')			select,insert,update,references	
+def	mysql	user	is_role	43	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_general_ci	enum('N','Y')			select,insert,update,references	
 def	mysql	user	Lock_tables_priv	21	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_general_ci	enum('N','Y')			select,insert,update,references	
 def	mysql	user	max_connections	39	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11) unsigned			select,insert,update,references	
 def	mysql	user	max_questions	37	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11) unsigned			select,insert,update,references	
@@ -480,6 +484,9 @@ NULL	mysql	procs_priv	Timestamp	timestamp	NULL	NULL	NULL	NULL	timestamp
 NULL	mysql	proxies_priv	With_grant	tinyint	NULL	NULL	NULL	NULL	tinyint(1)
 3.0000	mysql	proxies_priv	Grantor	char	77	231	utf8	utf8_bin	char(77)
 NULL	mysql	proxies_priv	Timestamp	timestamp	NULL	NULL	NULL	NULL	timestamp
+1.0000	mysql	roles_mapping	HostFk	char	60	60	latin1	latin1_bin	char(60)
+1.0000	mysql	roles_mapping	UserFk	char	16	16	latin1	latin1_bin	char(16)
+1.0000	mysql	roles_mapping	RoleFk	char	16	16	latin1	latin1_bin	char(16)
 3.0000	mysql	servers	Server_name	char	64	192	utf8	utf8_general_ci	char(64)
 3.0000	mysql	servers	Host	char	64	192	utf8	utf8_general_ci	char(64)
 3.0000	mysql	servers	Db	char	64	192	utf8	utf8_general_ci	char(64)
@@ -567,3 +574,4 @@ NULL	mysql	user	max_connections	int	NULL	NULL	NULL	NULL	int(11) unsigned
 NULL	mysql	user	max_user_connections	int	NULL	NULL	NULL	NULL	int(11)
 1.0000	mysql	user	plugin	char	64	64	latin1	latin1_swedish_ci	char(64)
 1.0000	mysql	user	authentication_string	text	65535	65535	utf8	utf8_bin	text
+3.0000	mysql	user	is_role	enum	1	3	utf8	utf8_general_ci	enum('N','Y')
diff --git a/mysql-test/suite/funcs_1/r/is_tables_mysql.result b/mysql-test/suite/funcs_1/r/is_tables_mysql.result
index c113e6d7fce..2b18129423b 100644
--- a/mysql-test/suite/funcs_1/r/is_tables_mysql.result
+++ b/mysql-test/suite/funcs_1/r/is_tables_mysql.result
@@ -428,6 +428,29 @@ user_comment	User proxy privileges
 Separator	-----------------------------------------------------
 TABLE_CATALOG	def
 TABLE_SCHEMA	mysql
+TABLE_NAME	roles_mapping
+TABLE_TYPE	BASE TABLE
+ENGINE	MYISAM_OR_MARIA
+VERSION	10
+ROW_FORMAT	Fixed
+TABLE_ROWS	#TBLR#
+AVG_ROW_LENGTH	#ARL#
+DATA_LENGTH	#DL#
+MAX_DATA_LENGTH	#MDL#
+INDEX_LENGTH	#IL#
+DATA_FREE	#DF#
+AUTO_INCREMENT	NULL
+CREATE_TIME	#CRT#
+UPDATE_TIME	#UT#
+CHECK_TIME	#CT#
+TABLE_COLLATION	latin1_swedish_ci
+CHECKSUM	NULL
+CREATE_OPTIONS	#CO#
+TABLE_COMMENT	#TC#
+user_comment	
+Separator	-----------------------------------------------------
+TABLE_CATALOG	def
+TABLE_SCHEMA	mysql
 TABLE_NAME	servers
 TABLE_TYPE	BASE TABLE
 ENGINE	MYISAM_OR_MARIA
diff --git a/mysql-test/suite/funcs_1/r/is_user_privileges.result b/mysql-test/suite/funcs_1/r/is_user_privileges.result
index 1ec1ffc4ce1..7b031ea5cbc 100644
--- a/mysql-test/suite/funcs_1/r/is_user_privileges.result
+++ b/mysql-test/suite/funcs_1/r/is_user_privileges.result
@@ -129,6 +129,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -171,6 +172,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -213,6 +215,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 #
 # Add GRANT OPTION db_datadict.* to testuser1;
 GRANT UPDATE ON db_datadict.* TO 'testuser1'@'localhost' WITH GRANT OPTION;
@@ -279,6 +282,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -321,6 +325,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -363,6 +368,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 # Establish connection testuser1 (user=testuser1)
 SELECT * FROM information_schema.user_privileges
 WHERE grantee LIKE '''testuser%'''
@@ -415,6 +421,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -457,6 +464,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -499,6 +507,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 SHOW GRANTS;
 Grants for testuser1@localhost
 GRANT USAGE ON *.* TO 'testuser1'@'localhost'
@@ -573,6 +582,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -615,6 +625,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -657,6 +668,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 GRANT SELECT ON *.* TO 'testuser1'@'localhost' WITH GRANT OPTION;
 #
 # Here <SELECT YES> is shown correctly for testuser1;
@@ -723,6 +735,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -765,6 +778,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -807,6 +821,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 # Switch to connection testuser1
 SELECT * FROM information_schema.user_privileges
 WHERE grantee LIKE '''testuser%'''
@@ -859,6 +874,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -901,6 +917,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -943,6 +960,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 SHOW GRANTS;
 Grants for testuser1@localhost
 GRANT SELECT ON *.* TO 'testuser1'@'localhost' WITH GRANT OPTION
@@ -1047,6 +1065,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -1089,6 +1108,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -1131,6 +1151,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 # Switch to connection testuser1
 SELECT * FROM information_schema.user_privileges
 WHERE grantee LIKE '''testuser%'''
@@ -1230,6 +1251,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -1272,6 +1294,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -1314,6 +1337,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 # Switch to connection testuser1
 SELECT * FROM information_schema.user_privileges
 WHERE grantee LIKE '''testuser%'''
@@ -1366,6 +1390,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -1408,6 +1433,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -1450,6 +1476,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 SHOW GRANTS;
 Grants for testuser1@localhost
 GRANT USAGE ON *.* TO 'testuser1'@'localhost'
@@ -1509,6 +1536,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -1551,6 +1579,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -1593,6 +1622,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 SHOW GRANTS;
 Grants for testuser1@localhost
 GRANT USAGE ON *.* TO 'testuser1'@'localhost'
@@ -1667,6 +1697,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser2
 Password	
@@ -1709,6 +1740,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 Host	localhost
 User	testuser3
 Password	
@@ -1751,6 +1783,7 @@ max_connections	0
 max_user_connections	0
 plugin	
 authentication_string	
+is_role	N
 # Switch to connection testuser1
 SELECT * FROM information_schema.user_privileges
 WHERE grantee LIKE '''testuser%'''
diff --git a/mysql-test/t/acl_roles_set_role-table-column-priv.test b/mysql-test/t/acl_roles_set_role-table-column-priv.test
index 11969758f0c..4334f4c430b 100644
--- a/mysql-test/t/acl_roles_set_role-table-column-priv.test
+++ b/mysql-test/t/acl_roles_set_role-table-column-priv.test
@@ -32,7 +32,7 @@ select current_user(), current_role();
 --sorted_result
 show grants;
 
---error ER_TABLEACCESS_DENIED_ERROR
+--error ER_COLUMNACCESS_DENIED_ERROR
 select * from mysql.roles_mapping;
 
 --sorted_result
diff --git a/mysql-test/t/acl_roles_show_grants.test b/mysql-test/t/acl_roles_show_grants.test
index 38b20e627a2..5cc11be6d40 100644
--- a/mysql-test/t/acl_roles_show_grants.test
+++ b/mysql-test/t/acl_roles_show_grants.test
@@ -40,7 +40,6 @@ select current_user(), current_role();
 --sorted_result
 show grants;
 
---error ER_DBACCESS_DENIED_ERROR
 show grants for test_user@localhost;
 --error ER_DBACCESS_DENIED_ERROR
 show grants for test_role1;
diff --git a/mysql-test/t/system_mysql_db_fix40123.test b/mysql-test/t/system_mysql_db_fix40123.test
index adb223a9e50..6501761b5bc 100644
--- a/mysql-test/t/system_mysql_db_fix40123.test
+++ b/mysql-test/t/system_mysql_db_fix40123.test
@@ -36,7 +36,7 @@ CREATE TABLE host (  Host char(60) binary DEFAULT '' NOT NULL,  Db char(64) bina
 
 CREATE TABLE user (   Host char(60) binary DEFAULT '' NOT NULL,   User char(16) binary DEFAULT '' NOT NULL,   Password char(41) binary DEFAULT '' NOT NULL,   Select_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Insert_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Update_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Delete_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Create_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Drop_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Reload_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Shutdown_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Process_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   File_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Grant_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   References_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Index_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Alter_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Show_db_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Super_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Create_tmp_table_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Lock_tables_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Execute_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Repl_slave_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   Repl_client_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL,   ssl_type enum('','ANY','X509', 'SPECIFIED') COLLATE utf8_general_ci DEFAULT '' NOT NULL,   ssl_cipher BLOB NOT NULL,   x509_issuer BLOB NOT NULL,   x509_subject BLOB NOT NULL,   max_questions int(11) unsigned DEFAULT 0  NOT NULL,   max_updates int(11) unsigned DEFAULT 0  NOT NULL,   max_connections int(11) unsigned DEFAULT 0  NOT NULL,   PRIMARY KEY Host (Host,User) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Users and global privileges';
 INSERT INTO user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0);
-	   INSERT INTO user VALUES ('localhost','','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0);
+INSERT INTO user VALUES ('localhost','','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0);
 
 CREATE TABLE func (   name char(64) binary DEFAULT '' NOT NULL,   ret tinyint(1) DEFAULT '0' NOT NULL,   dl char(128) DEFAULT '' NOT NULL,   type enum ('function','aggregate') COLLATE utf8_general_ci NOT NULL,   PRIMARY KEY (name) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin   comment='User defined functions';
 
@@ -77,7 +77,7 @@ CREATE TABLE index_stats (db_name varchar(64) NOT NULL, table_name varchar(64) N
 -- disable_query_log
 
 # Drop all tables created by this test
-DROP TABLE db, host, user, func, plugin, tables_priv, columns_priv, procs_priv, gtid_slave_pos, servers, help_category, help_keyword, help_relation, help_topic, proc, time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type, general_log, slow_log, event, ndb_binlog_index, proxies_priv, table_stats, column_stats, index_stats;
+DROP TABLE db, host, user, func, plugin, tables_priv, columns_priv, procs_priv, gtid_slave_pos, servers, help_category, help_keyword, help_relation, help_topic, proc, time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type, general_log, slow_log, event, ndb_binlog_index, proxies_priv, table_stats, column_stats, index_stats, roles_mapping;
 
 -- enable_query_log
 
diff --git a/mysql-test/t/system_mysql_db_fix50030.test b/mysql-test/t/system_mysql_db_fix50030.test
index a4718c91c26..21b37c54c9b 100644
--- a/mysql-test/t/system_mysql_db_fix50030.test
+++ b/mysql-test/t/system_mysql_db_fix50030.test
@@ -84,7 +84,7 @@ CREATE TABLE index_stats (db_name varchar(64) NOT NULL, table_name varchar(64) N
 -- disable_query_log
 
 # Drop all tables created by this test
-DROP TABLE db, host, user, func, plugin, tables_priv, columns_priv, procs_priv, gtid_slave_pos, servers, help_category, help_keyword, help_relation, help_topic, proc, time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type, general_log, slow_log, event, ndb_binlog_index, proxies_priv, table_stats, column_stats, index_stats;
+DROP TABLE db, host, user, func, plugin, tables_priv, columns_priv, procs_priv, gtid_slave_pos, servers, help_category, help_keyword, help_relation, help_topic, proc, time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type, general_log, slow_log, event, ndb_binlog_index, proxies_priv, table_stats, column_stats, index_stats, roles_mapping;
 
 -- enable_query_log
 
diff --git a/mysql-test/t/system_mysql_db_fix50117.test b/mysql-test/t/system_mysql_db_fix50117.test
index 5677d6337f0..17f5fe0b541 100644
--- a/mysql-test/t/system_mysql_db_fix50117.test
+++ b/mysql-test/t/system_mysql_db_fix50117.test
@@ -103,7 +103,7 @@ CREATE TABLE index_stats (db_name varchar(64) NOT NULL, table_name varchar(64) N
 -- disable_query_log
 
 # Drop all tables created by this test
-DROP TABLE db, host, user, func, plugin, tables_priv, columns_priv, procs_priv, gtid_slave_pos, servers, help_category, help_keyword, help_relation, help_topic, proc, time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type, general_log, slow_log, event, ndb_binlog_index, proxies_priv, table_stats, column_stats, index_stats;
+DROP TABLE db, host, user, func, plugin, tables_priv, columns_priv, procs_priv, gtid_slave_pos, servers, help_category, help_keyword, help_relation, help_topic, proc, time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type, general_log, slow_log, event, ndb_binlog_index, proxies_priv, table_stats, column_stats, index_stats, roles_mapping;
 
 -- enable_query_log
 
diff --git a/scripts/mysql_system_tables.sql b/scripts/mysql_system_tables.sql
index de6c33fb4f9..30bea5d9b0f 100644
--- a/scripts/mysql_system_tables.sql
+++ b/scripts/mysql_system_tables.sql
@@ -41,11 +41,7 @@ CREATE TABLE IF NOT EXISTS user (   Host char(60) binary DEFAULT '' NOT NULL, Us
 -- Remember for later if user table already existed
 set @had_user_table= @@warning_count != 0;
 
-CREATE TABLE IF NOT EXISTS roles_mapping (
-	HostFk char(60) binary DEFAULT '' NOT NULL,
-	UserFk char(16) binary DEFAULT '' NOT NULL,
-	RoleFk char(16) binary DEFAULT '' NOT NULL
-);
+CREATE TABLE IF NOT EXISTS roles_mapping (HostFk char(60) binary DEFAULT '' NOT NULL, UserFk char(16) binary DEFAULT '' NOT NULL, RoleFk char(16) binary DEFAULT '' NOT NULL);
 
 
 CREATE TABLE IF NOT EXISTS func (  name char(64) binary DEFAULT '' NOT NULL, ret tinyint(1) DEFAULT '0' NOT NULL, dl char(128) DEFAULT '' NOT NULL, type enum ('function','aggregate') COLLATE utf8_general_ci NOT NULL, PRIMARY KEY (name) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin   comment='User defined functions';
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 9716f7c251c..d1146a99113 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -6057,9 +6057,12 @@ bool check_grant_column(THD *thd, GRANT_INFO *grant,
                                              table_name, TRUE) : NULL;
     grant->version= grant_version;		/* purecov: inspected */
   }
-  if (!(grant_table= grant->grant_table_user) &&
-      !(grant_table_role= grant->grant_table_role))
-    goto err;					/* purecov: deadcode */
+
+  grant_table= grant->grant_table_user;
+  grant_table_role= grant->grant_table_role;
+
+  if (!grant_table && !grant_table_role)
+    goto err;
 
   if (grant_table)
   {
@@ -6187,14 +6190,12 @@ bool check_grant_all_columns(THD *thd, ulong want_access_arg,
                              Field_iterator_table_ref *fields)
 {
   Security_context *sctx= thd->security_ctx;
-  ulong want_access= want_access_arg;
+  ulong UNINIT_VAR(want_access);
   const char *table_name= NULL;
-
   const char* db_name;
   GRANT_INFO *grant;
-  /* Initialized only to make gcc happy */
-  GRANT_TABLE *grant_table= NULL;
-  GRANT_TABLE *grant_table_role= NULL;
+  GRANT_TABLE *UNINIT_VAR(grant_table);
+  GRANT_TABLE *UNINIT_VAR(grant_table_role);
   /*
      Flag that gets set if privilege checking has to be performed on column
      level.
@@ -6238,16 +6239,14 @@ bool check_grant_all_columns(THD *thd, ulong want_access_arg,
 
     if (want_access)
     {
+      ulong have_access= 0;
       if (grant_table)
       {
         GRANT_COLUMN *grant_column=
           column_hash_search(grant_table, field_name,
                              (uint) strlen(field_name));
         if (grant_column)
-        {
-          using_column_privileges= TRUE;
-          want_access&= ~grant_column->rights;
-        }
+          have_access= grant_column->rights;
       }
       if (grant_table_role)
       {
@@ -6255,13 +6254,12 @@ bool check_grant_all_columns(THD *thd, ulong want_access_arg,
           column_hash_search(grant_table_role, field_name,
                              (uint) strlen(field_name));
         if (grant_column)
-        {
-          using_column_privileges= TRUE;
-          want_access&= ~grant_column->rights;
-        }
+          have_access|= grant_column->rights;
       }
 
-      if (!want_access)
+      if (have_access)
+        using_column_privileges= TRUE;
+      if (want_access & ~have_access)
         goto err;
     }
   }
@@ -6580,8 +6578,10 @@ ulong get_column_grant(THD *thd, GRANT_INFO *grant,
     grant->version= grant_version;              /* purecov: inspected */
   }
 
-  if (!(grant_table= grant->grant_table_user) &&
-      !(grant_table_role= grant->grant_table_role))
+  grant_table= grant->grant_table_user;
+  grant_table_role= grant->grant_table_role;
+
+  if (!grant_table && !grant_table_role)
     priv= grant->privilege;
   else
   {
diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index 47c2e3bd406..7cc2caaa881 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -1470,18 +1470,17 @@ bool mysql_change_db(THD *thd, const LEX_STRING *new_db_name, bool force_switch)
   DBUG_PRINT("info",("Use database: %s", new_db_file_name.str));
 
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
-  db_access=
-    test_all_bits(sctx->master_access, DB_ACLS) ?
-    DB_ACLS :
-    acl_get(sctx->host,
-            sctx->ip,
-            sctx->priv_user,
-            new_db_file_name.str,
-            FALSE) | sctx->master_access;
-  if (sctx->priv_role[0])
+  if (test_all_bits(sctx->master_access, DB_ACLS))
+    db_access= DB_ACLS;
+  else
   {
-    /* include a possible currently set role for access */
-    db_access|= acl_get("", "", sctx->priv_role, new_db_file_name.str, FALSE);
+    db_access= acl_get(sctx->host, sctx->ip, sctx->priv_user,
+                        new_db_file_name.str, FALSE) | sctx->master_access;
+    if (sctx->priv_role[0])
+    {
+      /* include a possible currently set role for access */
+      db_access|= acl_get("", "", sctx->priv_role, new_db_file_name.str, FALSE);
+    }
   }
 
   if (!force_switch &&
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 293081c21db..281ca26b64f 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -148,7 +148,7 @@ enum enum_sql_command {
   SQLCOM_SHOW_TRIGGERS,
 
   SQLCOM_LOAD,SQLCOM_SET_OPTION,SQLCOM_LOCK_TABLES,SQLCOM_UNLOCK_TABLES,
-  SQLCOM_GRANT, SQLCOM_GRANT_ROLE,
+  SQLCOM_GRANT,
   SQLCOM_CHANGE_DB, SQLCOM_CREATE_DB, SQLCOM_DROP_DB, SQLCOM_ALTER_DB,
   SQLCOM_REPAIR, SQLCOM_REPLACE, SQLCOM_REPLACE_SELECT,
   SQLCOM_CREATE_FUNCTION, SQLCOM_DROP_FUNCTION,
@@ -169,7 +169,6 @@ enum enum_sql_command {
   SQLCOM_SHOW_WARNS, SQLCOM_EMPTY_QUERY, SQLCOM_SHOW_ERRORS,
   SQLCOM_SHOW_STORAGE_ENGINES, SQLCOM_SHOW_PRIVILEGES,
   SQLCOM_HELP, SQLCOM_CREATE_USER, SQLCOM_DROP_USER, SQLCOM_RENAME_USER,
-  SQLCOM_CREATE_ROLE, SQLCOM_DROP_ROLE, SQLCOM_REVOKE_ROLE,
   SQLCOM_REVOKE_ALL, SQLCOM_CHECKSUM,
   SQLCOM_CREATE_PROCEDURE, SQLCOM_CREATE_SPFUNCTION, SQLCOM_CALL,
   SQLCOM_DROP_PROCEDURE, SQLCOM_ALTER_PROCEDURE,SQLCOM_ALTER_FUNCTION,
@@ -197,6 +196,7 @@ enum enum_sql_command {
   SQLCOM_SHOW_USER_STATS, SQLCOM_SHOW_TABLE_STATS, SQLCOM_SHOW_INDEX_STATS,
   SQLCOM_SHOW_CLIENT_STATS,
   SQLCOM_SHOW_EXPLAIN, SQLCOM_SHUTDOWN,
+  SQLCOM_CREATE_ROLE, SQLCOM_DROP_ROLE, SQLCOM_GRANT_ROLE, SQLCOM_REVOKE_ROLE,
 
   /*
     When a command is added here, be sure it's also added in mysqld.cc
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 9d17d9c3e31..997ba7f97ea 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -4001,6 +4001,11 @@ end_with_restore_list:
     LEX_USER *grant_user= lex->grant_user;
     if (!grant_user)
       goto error;
+
+    if (grant_user->user.str &&
+        !strcmp(thd->security_ctx->priv_user, grant_user->user.str))
+      grant_user= &current_user;
+
     if (grant_user == &current_user ||
         grant_user == &current_role ||
         grant_user == &current_user_and_current_role ||
@@ -7752,7 +7757,7 @@ LEX_USER *create_definer(THD *thd, LEX_STRING *user_name, LEX_STRING *host_name)
 
 LEX_USER *get_current_user(THD *thd, LEX_USER *user)
 {
-  if (!user->user.str)  // current_user
+  if (user == &current_user)  // current_user
     return create_default_definer(thd);
 
   return user;