Fix removal of tables from cache when the database they are contained

within is dropped and lower_case_table_names is set. (Bug #8355)

mysql-test/r/lowercase_table2.result

@@ -141,3 +141,21 @@ select * from T1;
 a	b
 1	abc
 drop table T1;
+create database mysqltest_LC2;
+use mysqltest_LC2;
+create table myUC (i int);
+insert into myUC values (1),(2),(3);
+select * from myUC;
+i
+1
+2
+3
+use test;
+drop database mysqltest_LC2;
+create database mysqltest_LC2;
+use mysqltest_LC2;
+create table myUC (i int);
+select * from myUC;
+i
+use test;
+drop database mysqltest_LC2;

mysql-test/t/lowercase_table2.test

@@ -111,3 +111,20 @@ select * from T1;
 alter table T1 add index (a);
 select * from T1;
 drop table T1;
+
+#
+# Bug #8355: Tables not dropped from table cache on drop db
+#
+create database mysqltest_LC2;
+use mysqltest_LC2;
+create table myUC (i int);
+insert into myUC values (1),(2),(3);
+select * from myUC;
+use test;
+drop database mysqltest_LC2;
+create database mysqltest_LC2;
+use mysqltest_LC2;
+create table myUC (i int);
+select * from myUC;
+use test;
+drop database mysqltest_LC2;

sql/mysql_priv.h

@@ -750,7 +750,7 @@ bool close_temporary_table(THD *thd, const char *db, const char *table_name);
 void close_temporary(TABLE *table, bool delete_table=1);
 bool rename_temporary_table(THD* thd, TABLE *table, const char *new_db,
 			    const char *table_name);
-void remove_db_from_cache(const my_string db);
+void remove_db_from_cache(const char *db);
 void flush_tables();
 bool remove_table_from_cache(THD *thd, const char *db, const char *table,
 			     bool return_if_owned_by_thd=0);

sql/sql_base.cc

@@ -2864,8 +2864,18 @@ static void mysql_rm_tmp_tables(void)
 ** and afterwards delete those marked unused.
 */
 
-void remove_db_from_cache(const my_string db)
+void remove_db_from_cache(const char *db)
 {
+  char name_buff[NAME_LEN+1];
+  if (db && lower_case_table_names)
+  {
+    /*
+      convert database to lower case for comparision.
+    */
+    strmake(name_buff, db, sizeof(name_buff)-1);
+    my_casedn_str(files_charset_info, name_buff);
+    db= name_buff;
+  }
   for (uint idx=0 ; idx < open_cache.records ; idx++)
   {
     TABLE *table=(TABLE*) hash_element(&open_cache,idx);