Bug #53757 assert in mysql_truncate_by_delete

The assert was triggered if a connection executing TRUNCATE
on a InnoDB table was killed during open_tables.

This bug was fixed in the scope of Bug #45643
"InnoDB does not support replication of TRUNCATE TABLE".

This patch adds test coverage to innodb_mysql_sync.test.

mysql-test/r/innodb_mysql_sync.result

@@ -48,3 +48,21 @@ Warnings:
 Error	1146	Table 'test.t1' doesn't exist
 # Connection default
 SET DEBUG_SYNC= "RESET";
+#
+# Bug#53757 assert in mysql_truncate_by_delete
+#
+DROP TABLE IF EXISTS t1, t2;
+CREATE TABLE t1(a INT) Engine=InnoDB;
+CREATE TABLE t2(id INT);
+INSERT INTO t1 VALUES (1), (2);
+INSERT INTO t2 VALUES(connection_id());
+SET DEBUG_SYNC= "open_and_process_table SIGNAL opening WAIT_FOR killed";
+# Sending: (not reaped since connection is killed later)
+TRUNCATE t1;
+SET DEBUG_SYNC= "now WAIT_FOR opening";
+SELECT ((@id := id) - id) FROM t2;
+((@id := id) - id)
+0
+KILL @id;
+SET DEBUG_SYNC= "now SIGNAL killed";
+DROP TABLE t1, t2;

mysql-test/t/innodb_mysql_sync.test

@@ -80,6 +80,32 @@ disconnect con1;
 SET DEBUG_SYNC= "RESET";
 
 
+--echo #
+--echo # Bug#53757 assert in mysql_truncate_by_delete
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2;
+--enable_warnings
+
+CREATE TABLE t1(a INT) Engine=InnoDB;
+CREATE TABLE t2(id INT);
+INSERT INTO t1 VALUES (1), (2);
+
+connect (con1, localhost, root);
+INSERT INTO t2 VALUES(connection_id());
+SET DEBUG_SYNC= "open_and_process_table SIGNAL opening WAIT_FOR killed";
+--echo # Sending: (not reaped since connection is killed later)
+--send TRUNCATE t1
+
+connection default;
+SET DEBUG_SYNC= "now WAIT_FOR opening";
+SELECT ((@id := id) - id) FROM t2; 
+KILL @id;
+SET DEBUG_SYNC= "now SIGNAL killed";
+DROP TABLE t1, t2;
+
+
 # Check that all connections opened by test cases in this file are really
 # gone so execution of other tests won't be affected by their presence.
 --source include/wait_until_count_sessions.inc

sql/sql_base.cc

@@ -4429,6 +4429,7 @@ open_and_process_table(THD *thd, LEX *lex, TABLE_LIST *tables,
   bool error= FALSE;
   bool safe_to_ignore_table= FALSE;
   DBUG_ENTER("open_and_process_table");
+  DEBUG_SYNC(thd, "open_and_process_table");
 
   /*
     Ignore placeholders for derived tables. After derived tables