MDEV-13331 FK DELETE CASCADE does not honor innodb_lock_wait_timeout

row_ins_check_foreign_constraint(): On timeout,
return DB_LOCK_WAIT_TIMEOUT instead of DB_LOCK_WAIT,
so that the lock wait will be properly terminated.
Also, replace some redundant assignments.

It looks like this bug was introduced in MySQL 5.7.8 by:

    commit a97f6b91227c7e0fc3151cfe5421891e79c12d19
    Author: Annamalai Gurusami <annamalai.gurusami@oracle.com>
    Date:   Tue Jun 9 16:02:31 2015 +0530

        Bug #20953265 INNODB: FAILING ASSERTION: RESULT != FTS_INVALID

mysql-test/suite/innodb/r/foreign_key.result

@@ -209,7 +209,6 @@ UPDATE users SET name = 'qux' WHERE id = 1;
 connect  con1,localhost,root,,;
 SET innodb_lock_wait_timeout= 1;
 DELETE FROM matchmaking_groups WHERE id = 10;
-disconnect con1;
 connection default;
 COMMIT;
 SELECT * FROM matchmaking_group_users WHERE matchmaking_group_id NOT IN (SELECT id FROM matchmaking_groups);
@@ -222,3 +221,45 @@ id	name
 2	bar
 DROP TABLE
 matchmaking_group_maps, matchmaking_group_users, matchmaking_groups, users;
+#
+# MDEV-13331 FK DELETE CASCADE does not honor innodb_lock_wait_timeout
+#
+CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY) ENGINE=InnoDB;
+CREATE TABLE t2 (
+id INT NOT NULL PRIMARY KEY,
+ref_id INT NOT NULL DEFAULT 0,
+f INT NULL,
+FOREIGN KEY (ref_id) REFERENCES t1 (id) ON DELETE CASCADE
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (1),(2);
+INSERT INTO t2 VALUES (1,1,10),(2,2,20);
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL,
+  `ref_id` int(11) NOT NULL DEFAULT 0,
+  `f` int(11) DEFAULT NULL,
+  PRIMARY KEY (`id`),
+  KEY `ref_id` (`ref_id`),
+  CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`ref_id`) REFERENCES `t1` (`id`) ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+connection con1;
+BEGIN;
+UPDATE t2 SET f = 11 WHERE id = 1;
+connection default;
+SET innodb_lock_wait_timeout= 1;
+DELETE FROM t1 WHERE id = 1;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+connection con1;
+COMMIT;
+disconnect con1;
+connection default;
+SELECT * FROM t2;
+id	ref_id	f
+1	1	11
+2	2	20
+DELETE FROM t1 WHERE id = 1;
+SELECT * FROM t2;
+id	ref_id	f
+2	2	20
+DROP TABLE t2, t1;

mysql-test/suite/innodb/t/foreign_key.test

@@ -186,7 +186,6 @@ UPDATE users SET name = 'qux' WHERE id = 1;
 --connect (con1,localhost,root,,)
 SET innodb_lock_wait_timeout= 1;
 DELETE FROM matchmaking_groups WHERE id = 10;
---disconnect con1
 
 --connection default
 COMMIT;
@@ -200,4 +199,41 @@ SELECT * FROM users;
 DROP TABLE
 matchmaking_group_maps, matchmaking_group_users, matchmaking_groups, users;
 
+--echo #
+--echo # MDEV-13331 FK DELETE CASCADE does not honor innodb_lock_wait_timeout
+--echo #
+
+CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY) ENGINE=InnoDB;
+
+CREATE TABLE t2 (
+  id INT NOT NULL PRIMARY KEY,
+  ref_id INT NOT NULL DEFAULT 0,
+  f INT NULL,
+  FOREIGN KEY (ref_id) REFERENCES t1 (id) ON DELETE CASCADE
+) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES (1),(2);
+INSERT INTO t2 VALUES (1,1,10),(2,2,20);
+
+SHOW CREATE TABLE t2;
+
+--connection con1
+BEGIN;
+UPDATE t2 SET f = 11 WHERE id = 1;
+
+--connection default
+SET innodb_lock_wait_timeout= 1;
+--error ER_LOCK_WAIT_TIMEOUT
+DELETE FROM t1 WHERE id = 1;
+
+--connection con1
+COMMIT;
+--disconnect con1
+
+--connection default
+SELECT * FROM t2;
+DELETE FROM t1 WHERE id = 1;
+SELECT * FROM t2;
+DROP TABLE t2, t1;
+
 --source include/wait_until_count_sessions.inc

storage/innobase/row/row0ins.cc

@@ -1759,13 +1759,6 @@ row_ins_check_foreign_constraint(
 		cmp = cmp_dtuple_rec(entry, rec, offsets);
 
 		if (cmp == 0) {
-
-			ulint	lock_type;
-
-			lock_type = skip_gap_lock
-				? LOCK_REC_NOT_GAP
-				: LOCK_ORDINARY;
-
 			if (rec_get_deleted_flag(rec,
 						 rec_offs_comp(offsets))) {
 				/* In delete-marked records, DB_TRX_ID must
@@ -1775,7 +1768,9 @@ row_ins_check_foreign_constraint(
 							    offsets));
 
 				err = row_ins_set_shared_rec_lock(
-					lock_type, block,
+					skip_gap_lock
+					? LOCK_REC_NOT_GAP
+					: LOCK_ORDINARY, block,
 					rec, check_index, offsets, thr);
 				switch (err) {
 				case DB_SUCCESS_LOCKED_REC:
@@ -1857,23 +1852,21 @@ row_ins_check_foreign_constraint(
 		} else {
 			ut_a(cmp < 0);
 
-			err = DB_SUCCESS;
-
-			if (!skip_gap_lock) {
-				err = row_ins_set_shared_rec_lock(
+			err = skip_gap_lock
+				? DB_SUCCESS
+				: row_ins_set_shared_rec_lock(
 					LOCK_GAP, block,
 					rec, check_index, offsets, thr);
-			}
 
 			switch (err) {
 			case DB_SUCCESS_LOCKED_REC:
+				err = DB_SUCCESS;
+				/* fall through */
 			case DB_SUCCESS:
 				if (check_ref) {
 					err = DB_NO_REFERENCED_ROW;
 					row_ins_foreign_report_add_err(
 						trx, foreign, rec, entry);
-				} else {
-					err = DB_SUCCESS;
 				}
 			default:
 				break;
@@ -1921,19 +1914,11 @@ do_possible_lock_wait:
 
 		thr->lock_state = QUE_THR_LOCK_NOLOCK;
 
-		DBUG_PRINT("to_be_dropped",
-			   ("table: %s", check_table->name.m_name));
-		if (check_table->to_be_dropped) {
-			/* The table is being dropped. We shall timeout
-			this operation */
-			err = DB_LOCK_WAIT_TIMEOUT;
-
-			goto exit_func;
-		}
-
+		err = check_table->to_be_dropped
+			? DB_LOCK_WAIT_TIMEOUT
+			: trx->error_state;
 	}
 
-
 exit_func:
 	if (heap != NULL) {
 		mem_heap_free(heap);