# MDEV-20946 Hard FTWRL deadlock under user level locks
#
# Deadlock detector should resolve conflicts between FTWRL and user locks.

--source include/have_debug_sync.inc
--source include/count_sessions.inc

CREATE TABLE t1(a INT);
SELECT GET_LOCK("l1", 0);

connect(con1,localhost,root,,);
LOCK TABLES t1 WRITE;

connection default;
set debug_sync='mdl_acquire_lock_wait SIGNAL ftwrl';
send FLUSH TABLES WITH READ LOCK;
# At this point "default" is waiting for tables to be unlocked from
# LOCK TABLES WRITE issued by "con1".

connection con1;
set debug_sync='now WAIT_FOR ftwrl';
# The lock in the following GET_LOCK cannot be acquired since "default" holds
# a lock on "l1" and is waiting in FLUSH TABLES for con1.
--error ER_LOCK_DEADLOCK
SELECT GET_LOCK("l1", 1000);
disconnect con1;  # Performs an implicit UNLOCK TABLES.

connection default;
reap;
SELECT RELEASE_LOCK("l1");
UNLOCK TABLES;
DROP TABLE t1;

set debug_sync='reset';

--source include/wait_until_count_sessions.inc