MDEV-22939 Server crashes in row_make_new_pathname()

The statement ALTER TABLE...DISCARD TABLESPACE is problematic, because its designed purpose is to break the referential integrity of the data dictionary and make a table point to nowhere. ha_innobase::commit_inplace_alter_table(): Check whether the table has been discarded. (This is a bit late to check it, right before committing the change.) Previously, we performed this check only in a specific branch of the function commit_set_autoinc(). Note: We intentionally allow non-rebuilding ALTER TABLE even if the tablespace has been discarded, to remain compatible with MySQL. (See the various tests with "wl5522" in the name, such as innodb.innodb-wl5522.) The test case would crash starting with 10.3 only, but it does not hurt to minimize the code and test difference between 10.2 and 10.3.

Author: dr-m

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

@@ -60,3 +60,13 @@ CREATE TABLE t1(a INT NOT NULL UNIQUE) ENGINE=InnoDB;
 INSERT INTO t1 SELECT * FROM seq_1_to_128;
 ALTER TABLE t1 ADD b TINYINT AUTO_INCREMENT PRIMARY KEY, DROP KEY a;
 DROP TABLE t1;
+#
+# MDEV-22939 Server crashes in row_make_new_pathname()
+#
+CREATE TABLE t (a INT) ENGINE=INNODB;
+ALTER TABLE t DISCARD TABLESPACE;
+ALTER TABLE t ENGINE INNODB;
+ERROR HY000: Tablespace has been discarded for table `t`
+ALTER TABLE t FORCE;
+ERROR HY000: Tablespace has been discarded for table `t`
+DROP TABLE t;

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

@@ -68,3 +68,14 @@ CREATE TABLE t1(a INT NOT NULL UNIQUE) ENGINE=InnoDB;
 INSERT INTO t1 SELECT * FROM seq_1_to_128;
 ALTER TABLE t1 ADD b TINYINT AUTO_INCREMENT PRIMARY KEY, DROP KEY a;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-22939 Server crashes in row_make_new_pathname()
+--echo #
+CREATE TABLE t (a INT) ENGINE=INNODB;
+ALTER TABLE t DISCARD TABLESPACE;
+--error ER_TABLESPACE_DISCARDED
+ALTER TABLE t ENGINE INNODB;
+--error ER_TABLESPACE_DISCARDED
+ALTER TABLE t FORCE;
+DROP TABLE t;

storage/innobase/handler/handler0alter.cc

@@ -7209,12 +7209,6 @@ commit_set_autoinc(
  && (ha_alter_info->create_info->used_fields
  & HA_CREATE_USED_AUTO)) {
 
-if (dict_table_is_discarded(ctx->old_table)) {
-my_error(ER_TABLESPACE_DISCARDED, MYF(0),
- old_table->s->table_name.str);
-DBUG_RETURN(true);
-}
-
 /* An AUTO_INCREMENT value was supplied by the user.
 It must be persisted to the data file. */
 const Field*	ai	= old_table->found_next_number_field;
@@ -8411,9 +8405,15 @@ ha_innobase::commit_inplace_alter_table(
 = static_cast<ha_innobase_inplace_ctx*>(*pctx);
 
 DBUG_ASSERT(new_clustered == ctx->need_rebuild());
-
-fail = commit_set_autoinc(ha_alter_info, ctx, altered_table,
- table);
+if (ctx->need_rebuild()
+ && dict_table_is_discarded(ctx->old_table)) {
+my_error(ER_TABLESPACE_DISCARDED, MYF(0),
+ table->s->table_name.str);
+fail = true;
+} else {
+fail = commit_set_autoinc(ha_alter_info, ctx,
+ altered_table, table);
+}
 
 if (fail) {
 } else if (ctx->need_rebuild()) {