MDEV-13721 Assertion is_lock_owner() failed in mysql_rm_table_no_locks

This happened when trying to do delete a sequence hidden by a temporary
table.
Fixed by ignoring non-sequence temporary tables when trying to drop
sequences.
Signed-off-by: Monty <monty@mariadb.org>

mysql-test/suite/sql_sequence/create.result

@@ -571,3 +571,65 @@ ERROR 42S02: 'test.s' is not a SEQUENCE
 show create sequence s2;
 ERROR 42S02: 'test.s2' is not a SEQUENCE
 drop table s,s2;
+#
+# MDEV-13721 Assertion is_lock_owner() failed in mysql_rm_table_no_locks
+#
+create or replace sequence s;
+create temporary table s (i int);
+drop sequence s;
+show create table s;
+Table	Create Table
+s	CREATE TEMPORARY TABLE `s` (
+  `i` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table s;
+create or replace sequence s;
+create temporary sequence s;
+show create table s;
+Table	Create Table
+s	CREATE TEMPORARY TABLE `s` (
+  `next_not_cached_value` bigint(21) NOT NULL,
+  `minimum_value` bigint(21) NOT NULL,
+  `maximum_value` bigint(21) NOT NULL,
+  `start_value` bigint(21) NOT NULL COMMENT 'start value when sequences is created or value if RESTART is used',
+  `increment` bigint(21) NOT NULL COMMENT 'increment value',
+  `cache_size` bigint(21) unsigned NOT NULL,
+  `cycle_option` tinyint(1) unsigned NOT NULL COMMENT '0 if no cycles are allowed, 1 if the sequence should begin a new cycle when maximum_value is passed',
+  `cycle_count` bigint(21) NOT NULL COMMENT 'How many cycles have been done'
+) ENGINE=MyISAM SEQUENCE=1
+drop sequence s;
+show create table s;
+Table	Create Table
+s	CREATE TABLE `s` (
+  `next_not_cached_value` bigint(21) NOT NULL,
+  `minimum_value` bigint(21) NOT NULL,
+  `maximum_value` bigint(21) NOT NULL,
+  `start_value` bigint(21) NOT NULL COMMENT 'start value when sequences is created or value if RESTART is used',
+  `increment` bigint(21) NOT NULL COMMENT 'increment value',
+  `cache_size` bigint(21) unsigned NOT NULL,
+  `cycle_option` tinyint(1) unsigned NOT NULL COMMENT '0 if no cycles are allowed, 1 if the sequence should begin a new cycle when maximum_value is passed',
+  `cycle_count` bigint(21) NOT NULL COMMENT 'How many cycles have been done'
+) ENGINE=MyISAM SEQUENCE=1
+drop table s;
+create or replace sequence s;
+create temporary sequence s;
+drop temporary sequence s;
+show create table s;
+Table	Create Table
+s	CREATE TABLE `s` (
+  `next_not_cached_value` bigint(21) NOT NULL,
+  `minimum_value` bigint(21) NOT NULL,
+  `maximum_value` bigint(21) NOT NULL,
+  `start_value` bigint(21) NOT NULL COMMENT 'start value when sequences is created or value if RESTART is used',
+  `increment` bigint(21) NOT NULL COMMENT 'increment value',
+  `cache_size` bigint(21) unsigned NOT NULL,
+  `cycle_option` tinyint(1) unsigned NOT NULL COMMENT '0 if no cycles are allowed, 1 if the sequence should begin a new cycle when maximum_value is passed',
+  `cycle_count` bigint(21) NOT NULL COMMENT 'How many cycles have been done'
+) ENGINE=MyISAM SEQUENCE=1
+drop table s;
+create temporary sequence s;
+drop temporary table s;
+create temporary table s (i int);
+drop temporary sequence s;
+ERROR 42S02: Unknown SEQUENCE: 'test.s'
+drop table s;

mysql-test/suite/sql_sequence/create.test

@@ -419,3 +419,33 @@ show create sequence s;
 --error ER_NOT_SEQUENCE
 show create sequence s2;
 drop table s,s2;
+
+--echo #
+--echo # MDEV-13721 Assertion is_lock_owner() failed in mysql_rm_table_no_locks
+--echo #
+
+create or replace sequence s;
+create temporary table s (i int);
+drop sequence s;
+show create table s;
+drop table s;
+
+create or replace sequence s;
+create temporary sequence s;
+show create table s;
+drop sequence s;
+show create table s;
+drop table s;
+
+create or replace sequence s;
+create temporary sequence s;
+drop temporary sequence s;
+show create table s;
+drop table s;
+
+create temporary sequence s;
+drop temporary table s;
+create temporary table s (i int);
+--error ER_UNKNOWN_SEQUENCES
+drop temporary sequence s;
+drop table s;

sql/sql_table.cc

@@ -1990,7 +1990,7 @@ int write_bin_log(THD *thd, bool clear_error,
    tables		List of tables to delete
    if_exists		If 1, don't give error if one table doesn't exists
    drop_temporary       1 if DROP TEMPORARY
-   drop_seqeunce        1 if DROP SEQUENCE
+   drop_sequence        1 if DROP SEQUENCE
 
   NOTES
     Will delete all tables that can be deleted and give a compact error
@@ -2038,6 +2038,25 @@ bool mysql_rm_table(THD *thd,TABLE_LIST *tables, bool if_exists,
 
     if (!thd->locked_tables_mode)
     {
+      if (drop_sequence)
+      {
+        /* We are trying to drop a sequence.
+           Change all temporary tables that are not sequences to
+           normal tables so that we can try to drop them instead.
+           If we don't do this, we will get an error 'not a sequence'
+           when trying to drop a sequence that is hidden by a temporary
+           table.
+        */
+        for (table= tables; table; table= table->next_global)
+        {
+          if (table->open_type == OT_TEMPORARY_OR_BASE &&
+            is_temporary_table(table) && !table->table->s->sequence)
+          {
+            thd->mark_tmp_table_as_free_for_reuse(table->table);
+            table->table= NULL;
+          }
+        }
+      }
       if (lock_table_names(thd, tables, NULL,
                            thd->variables.lock_wait_timeout, 0))
         DBUG_RETURN(true);