Adjust the instrumentation and test

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

 --source include/have_innodb.inc
-#
-# MDEV-11995 ALTER TABLE proceeds despite reporting ER_TOO_LONG_KEY error
-#
-set @@sql_mode=strict_trans_tables;
-create table t1(a text not null) row_format=dynamic engine=innodb;
-create index idx1 on t1(a(3073));
-show create table t1;
-drop table t1;
-set @@sql_mode=default;
+CREATE TABLE t1 (
+  id1 INT AUTO_INCREMENT PRIMARY KEY, id2 VARCHAR(30) NOT NULL UNIQUE,
+  id3 DATETIME
+) ENGINE=InnoDB;
+ALTER TABLE t1 CHANGE COLUMN id2 id4 VARCHAR(40) NOT NULL;
+SELECT * FROM t1 WHERE id4 LIKE 'a';
+DROP TABLE t1;

mysql-test/suite/innodb_fts/r/truncate.result

@@ -20,12 +20,12 @@ set i = i + 1;
 end while;
 end|
 CALL insert_t2(15);
-SET SESSION debug="+d,innodb_invalid_read_after_truncate";
+SET @save_dbug = @@SESSION.DEBUG_DBUG;
+SET DEBUG_DBUG = '+d,innodb_invalid_read_after_truncate';
 INSERT INTO t1 (a,d,b,c) VALUES (
 '7795','6',repeat('uololoaroolccaaruolraloouuoocorrcorurlu','1'),
 repeat('orouculcaocuocloooolooloooaorlroclouulrrucclulalouaulrluorooaclllluuorc
 cuullucocraloracurooulrooauuar','1'));
-SET SESSION debug="-d,innodb_invalid_read_after_truncate";
+SET DEBUG_DBUG = @save_dbug;
 DROP PROCEDURE insert_t2;
-DROP TABLE t1;
-DROP TABLE t2;
+DROP TABLE t1,t2;

mysql-test/suite/innodb_fts/t/truncate.test

---source include/have_innodb_64k.inc
+--source include/have_innodb.inc
 --source include/have_debug.inc
 
 --echo #
@@ -35,16 +35,16 @@ delimiter ;|
 
 CALL insert_t2(15);
 
-SET SESSION debug="+d,innodb_invalid_read_after_truncate";
+SET @save_dbug = @@SESSION.DEBUG_DBUG;
+SET DEBUG_DBUG = '+d,innodb_invalid_read_after_truncate';
 
 INSERT INTO t1 (a,d,b,c) VALUES (
 '7795','6',repeat('uololoaroolccaaruolraloouuoocorrcorurlu','1'),
 repeat('orouculcaocuocloooolooloooaorlroclouulrrucclulalouaulrluorooaclllluuorc
 cuullucocraloracurooulrooauuar','1'));
 
-SET SESSION debug="-d,innodb_invalid_read_after_truncate";
+SET DEBUG_DBUG = @save_dbug;
 
 DROP PROCEDURE insert_t2;
 
-DROP TABLE t1;
-DROP TABLE t2;
+DROP TABLE t1,t2;

storage/innobase/buf/buf0rea.cc

@@ -176,17 +176,16 @@ buf_read_page_low(
 		dst = ((buf_block_t*) bpage)->frame;
 	}
 
-	/* This debug code is only for 5.7. In trunk, with newDD,
-	the space->name is no longer same as table name. */
-	DBUG_EXECUTE_IF("innodb_invalid_read_after_truncate",
-		fil_space_t*	space = fil_space_get(page_id.space());
-
-		if (space != NULL && strcmp(space->name, "test/t1") == 0
-		    && page_id.page_no() == space->size - 1) {
-			type = IORequest::READ;
-			sync = true;
-		}
-	);
+	DBUG_EXECUTE_IF(
+		"innodb_invalid_read_after_truncate",
+		if (fil_space_t* space = fil_space_acquire(page_id.space())) {
+			if (!strcmp(space->name, "test/t1")
+			    && page_id.page_no() == space->size - 1) {
+				type = 0;
+				sync = true;
+			}
+			fil_space_release(space);
+		});
 
 	IORequest	request(type | IORequest::READ);
 
@@ -333,18 +332,18 @@ buf_read_ahead_random(
 	that is, reside near the start of the LRU list. */
 
 	for (i = low; i < high; i++) {
-		/* This debug code is only for 5.7. In trunk, with newDD,
-		the space->name is no longer same as table name. */
-		DBUG_EXECUTE_IF("innodb_invalid_read_after_truncate",
-			fil_space_t*	space = fil_space_get(page_id.space());
-
-			if (space != NULL
-			    && strcmp(space->name, "test/t1") == 0) {
-				high = space->size;
-				buf_pool_mutex_exit(buf_pool);
-				goto read_ahead;
-			}
-		);
+		DBUG_EXECUTE_IF(
+			"innodb_invalid_read_after_truncate",
+			if (fil_space_t* space = fil_space_acquire(
+				    page_id.space())) {
+				bool skip = !strcmp(space->name, "test/t1");
+				fil_space_release(space);
+				if (skip) {
+					high = space->size;
+					buf_pool_mutex_exit(buf_pool);
+					goto read_ahead;
+				}
+			});
 
 		const buf_page_t*	bpage = buf_page_hash_get(
 			buf_pool, page_id_t(page_id.space(), i));