MDEV-10748 Server crashes in ha_maria::implicit_commit

Problem was in a combination of LOCK TABLES on several Aria
tables followed by an ALTER TABLE. After the ALTER TABLE there
was a force close + reopen of the alter table. The close failed
because the table was still part of a transaction.

Fixed by calling extra(HA_EXTRA_PREPARE_FOR_FORCED_CLOSE) as
part of closing the table, which ensures that the table is not
anymore part of the current transaction.

mysql-test/suite/maria/lock.result

@@ -109,4 +109,16 @@ ALTER TABLE t1 ADD UNIQUE KEY (f1);
 ERROR 23000: Duplicate entry 'foo' for key 'f1'
 ALTER TABLE t1 ADD KEY (f2);
 DROP TABLE t1;
+#
+# MDEV-10748 Server crashes in ha_maria::implicit_commit upon ALTER TABLE
+#
+CREATE TABLE t1 (a INT, b INT) ENGINE=Aria;
+SELECT * FROM t1;
+a	b
+CREATE TABLE t2 (c INT) ENGINE=Aria;
+LOCK TABLE t2 READ, t1 WRITE;
+ALTER TABLE t1 CHANGE b a INT;
+ERROR 42S21: Duplicate column name 'a'
+UNLOCK TABLES;
+DROP TABLE t1, t2;
 # End of 10.2 tests

mysql-test/suite/maria/lock.test

@@ -118,4 +118,21 @@ ALTER TABLE t1 ADD UNIQUE KEY (f1);
 ALTER TABLE t1 ADD KEY (f2);
 DROP TABLE t1;
 
+
+--echo #
+--echo # MDEV-10748 Server crashes in ha_maria::implicit_commit upon ALTER TABLE
+--echo #
+
+CREATE TABLE t1 (a INT, b INT) ENGINE=Aria;
+SELECT * FROM t1;
+CREATE TABLE t2 (c INT) ENGINE=Aria;
+ 
+LOCK TABLE t2 READ, t1 WRITE;
+--error ER_DUP_FIELDNAME
+ALTER TABLE t1 CHANGE b a INT;
+ 
+# Cleanup
+UNLOCK TABLES;
+DROP TABLE t1, t2;
+
 --echo # End of 10.2 tests

sql/sql_base.cc

@@ -2426,9 +2426,17 @@ Locked_tables_list::reopen_tables(THD *thd, bool need_reopen)
     {
       if (!table_list->table || !table_list->table->needs_reopen())
         continue;
-      /* no need to remove the table from the TDC here, thus (TABLE*)1 */
-      close_all_tables_for_name(thd, table_list->table->s,
-                                HA_EXTRA_NOT_USED, (TABLE*)1);
+      for (TABLE **prev= &thd->open_tables; *prev; prev= &(*prev)->next)
+      {
+        if (*prev == table_list->table)
+        {
+          thd->locked_tables_list.unlink_from_list(thd, table_list, false);
+          mysql_lock_remove(thd, thd->lock, *prev);
+          (*prev)->file->extra(HA_EXTRA_PREPARE_FOR_FORCED_CLOSE);
+          close_thread_table(thd, prev);
+          break;
+        }
+      }
       DBUG_ASSERT(table_list->table == NULL);
     }
     else