MDEV-17885 TRUNCATE on temporary table causes ER_GET_ERRNO

ha_innobase::truncate(): Because CREATE TEMPORARY TABLE
allows invalid table options when innodb_file_per_table=1,
do allow them also in TRUNCATE for temporary tables.

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

@@ -30,3 +30,12 @@ SELECT * FROM t1;
 a
 1
 DROP TABLE t1;
+#
+# MDEV-17885 TRUNCATE on temporary table causes ER_GET_ERRNO
+#
+CREATE TEMPORARY TABLE t1 (a INT) ENCRYPTED=NO ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1);
+TRUNCATE t1;
+SELECT * FROM t1;
+a
+DROP TEMPORARY TABLE t1;

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

@@ -41,3 +41,12 @@ CREATE TABLE t1 (a INT) ENGINE=InnoDB;
 --move_file $MYSQLD_DATADIR/test/hidden.frm $MYSQLD_DATADIR/test/t1.frm
 SELECT * FROM t1;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-17885 TRUNCATE on temporary table causes ER_GET_ERRNO
+--echo #
+CREATE TEMPORARY TABLE t1 (a INT) ENCRYPTED=NO ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1);
+TRUNCATE t1;
+SELECT * FROM t1;
+DROP TEMPORARY TABLE t1;

storage/innobase/handler/ha_innodb.cc

@@ -13531,7 +13531,8 @@ int ha_innobase::truncate()
 		row_mysql_unlock_data_dictionary(trx);
 	} else {
 		err = create(name, table, &info,
-			     dict_table_is_file_per_table(ib_table), trx);
+			     ib_table->is_temporary()
+			     || dict_table_is_file_per_table(ib_table), trx);
 	}
 
 	trx_free_for_mysql(trx);