MDEV-17946 : Unsorted acl_dbs after RENAME USER

mysql-test/main/grant.result

@@ -2770,3 +2770,12 @@ CREATE USER bar2@localhost;
 RENAME USER foo@localhost TO bar1@localhost, bar1@localhost TO bar3@localhost;
 DROP USER bar2@localhost;
 DROP USER bar3@localhost;
+#
+# MDEV-17946 : Unsorted acl_dbs after RENAME USER
+#
+CREATE USER foo;
+GRANT SELECT ON test.* TO foo;
+RENAME USER '' TO 'name';
+GRANT UPDATE ON test.* TO foo;
+RENAME USER 'name' to '';
+DROP USER foo;

mysql-test/main/grant.test

@@ -2267,3 +2267,14 @@ CREATE USER bar2@localhost;
 RENAME USER foo@localhost TO bar1@localhost, bar1@localhost TO bar3@localhost;
 DROP USER bar2@localhost;
 DROP USER bar3@localhost;
+
+--echo #
+--echo # MDEV-17946 : Unsorted acl_dbs after RENAME USER
+--echo #
+CREATE USER foo;
+GRANT SELECT ON test.* TO foo;
+RENAME USER '' TO 'name';
+GRANT UPDATE ON test.* TO foo;
+RENAME USER 'name' to '';
+DROP USER foo;
+

sql/sql_acl.cc

@@ -10368,6 +10368,8 @@ bool mysql_rename_user(THD *thd, List <LEX_USER> &list)
     rebuild_acl_users();
   }
 
+  /* Rebuild 'acl_dbs' since 'acl_users' has been modified */
+  rebuild_acl_dbs();
 
   /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
   rebuild_check_host();