From 9c686c8a68af12b3a491dc8049b7ddc50db8010e Mon Sep 17 00:00:00 2001
From: unknown <bar@mysql.com>
Date: Thu, 18 May 2006 12:21:13 +0500
Subject: [PATCH] Bug#19392 Rename Database: Crash if case change Problem:
 Renaming a database to itself crashed server. It hapenned because of wrong
 DBUG_ASSERT. Fix: removing wrong DBUG_ASSERT. Now it reports a correct error
 message "database alreadt exists".

mysql-test/r/renamedb.result:
  Adding test case
mysql-test/t/renamedb.test:
  Adding test case
sql/sql_db.cc:
  DBUG_ASSERT crashed server when renaming a database to itself.
---
 mysql-test/r/renamedb.result | 4 ++++
 mysql-test/t/renamedb.test   | 8 ++++++++
 sql/sql_db.cc                | 6 +++---
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/mysql-test/r/renamedb.result b/mysql-test/r/renamedb.result
index 26ae42e72aa..b22322fbe8d 100644
--- a/mysql-test/r/renamedb.result
+++ b/mysql-test/r/renamedb.result
@@ -27,3 +27,7 @@ a
 2
 3
 drop database testdb2;
+create database testdb1;
+rename database testdb1 to testdb1;
+ERROR HY000: Can't create database 'testdb1'; database exists
+drop database testdb1;
diff --git a/mysql-test/t/renamedb.test b/mysql-test/t/renamedb.test
index 5cfb2ce0c12..1e71adb3bf3 100644
--- a/mysql-test/t/renamedb.test
+++ b/mysql-test/t/renamedb.test
@@ -16,3 +16,11 @@ select database();
 show tables;
 select a from t1 order by a;
 drop database testdb2;
+
+#
+# Bug#19392 Rename Database: Crash if case change
+#
+create database testdb1;
+--error 1007
+rename database testdb1 to testdb1;
+drop database testdb1;
diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index 3d035359b6f..cb43bb77def 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -134,9 +134,9 @@ void lock_db_delete(const char *name, uint length)
 {
   my_dblock_t *opt;
   safe_mutex_assert_owner(&LOCK_lock_db);
-  opt= (my_dblock_t *)hash_search(&lock_db_cache, (const byte*) name, length);
-  DBUG_ASSERT(opt != NULL);
-  hash_delete(&lock_db_cache, (byte*) opt);
+  if (opt= (my_dblock_t *)hash_search(&lock_db_cache,
+                                      (const byte*) name, length))
+    hash_delete(&lock_db_cache, (byte*) opt);
 }