From b1c41e112cf14bd32af3d24242d7458e074cd505 Mon Sep 17 00:00:00 2001
From: Vladislav Vaintroub <wlad@mariadb.com>
Date: Sat, 8 Dec 2018 01:16:05 +0100
Subject: [PATCH] MDEV-17932 : assertion in multi RENAME USER command.

Sort acl_users inside the mysql_rename_user()'s loop, after every
successful iteration.

This is needed because on the next loop's iteration find_user_exact()
is used, which requires correct sorting by name.
---
 mysql-test/main/grant.result | 8 ++++++++
 mysql-test/main/grant.test   | 9 +++++++++
 sql/sql_acl.cc               | 2 +-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/mysql-test/main/grant.result b/mysql-test/main/grant.result
index 74f86edd4ea..2b92a2bd797 100644
--- a/mysql-test/main/grant.result
+++ b/mysql-test/main/grant.result
@@ -2762,3 +2762,11 @@ DROP USER dummy@localhost;
 #
 # End of 10.2 tests
 #
+#
+# MDEV-17932 : Assertion upon double RENAME USER
+#
+CREATE USER foo@localhost;
+CREATE USER bar2@localhost;
+RENAME USER foo@localhost TO bar1@localhost, bar1@localhost TO bar3@localhost;
+DROP USER bar2@localhost;
+DROP USER bar3@localhost;
diff --git a/mysql-test/main/grant.test b/mysql-test/main/grant.test
index f54c4bd981d..10da0af4ea5 100644
--- a/mysql-test/main/grant.test
+++ b/mysql-test/main/grant.test
@@ -2258,3 +2258,12 @@ DROP USER dummy@localhost;
 --echo #
 --echo # End of 10.2 tests
 --echo #
+
+--echo #
+--echo # MDEV-17932 : Assertion upon double RENAME USER
+--echo #
+CREATE USER foo@localhost;
+CREATE USER bar2@localhost;
+RENAME USER foo@localhost TO bar1@localhost, bar1@localhost TO bar3@localhost;
+DROP USER bar2@localhost;
+DROP USER bar3@localhost;
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 7f7bd447bad..f1612a7927f 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -10365,9 +10365,9 @@ bool mysql_rename_user(THD *thd, List <LEX_USER> &list)
       continue;
     }
     some_users_renamed= TRUE;
+    rebuild_acl_users();
   }
 
-  rebuild_acl_users();
 
   /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
   rebuild_check_host();