MDEV-29038 XA assertions failing in binlog_rollback and binlog_commit

ONLINE ALTER TABLE adds binlog handlerton into ha_list, so any
rollback command can end up calling binlog_rollback having no cache_mngr,
if binlog is not enabled.

The assertion should be fixed in the same manner as DBUG_ASSERT(WSREP(thd))

mysql-test/main/alter_table_online_debug.result

@@ -952,5 +952,32 @@ alter table t1 force;
 drop table t1, t2;
 set debug_sync= reset;
 #
+# MDEV-29038 XA assertions failing in binlog_rollback and binlog_commit
+#
+create table t (a int) engine=innodb;
+insert into t values (1);
+xa begin 'xid';
+set debug_sync= 'now wait_for downgraded';
+connect  con1,localhost,root,,test;
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+alter table t force, algorithm=copy, lock=none;
+connection default;
+insert into t values (2);
+set debug_sync= 'now signal goforit';
+xa end 'xid';
+xa rollback 'xid';
+xa begin 'xid';
+connection con1;
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+alter table t force, algorithm=copy, lock=none;
+connection default;
+set debug_sync= 'now wait_for downgraded';
+insert into t values (3);
+set debug_sync= 'now signal goforit';
+xa end 'xid';
+xa commit 'xid' one phase;
+drop table t;
+set debug_sync= reset;
+#
 # End of 11.2 tests
 #

mysql-test/main/alter_table_online_debug.test

@@ -1113,6 +1113,45 @@ alter table t1 force;
 drop table t1, t2;
 set debug_sync= reset;
 
+--echo #
+--echo # MDEV-29038 XA assertions failing in binlog_rollback and binlog_commit
+--echo #
+create table t (a int) engine=innodb;
+insert into t values (1);
+xa begin 'xid';
+--send
+set debug_sync= 'now wait_for downgraded';
+
+--connect (con1,localhost,root,,test)
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+--send
+alter table t force, algorithm=copy, lock=none;
+
+--connection default
+--reap
+insert into t values (2);
+set debug_sync= 'now signal goforit';
+xa end 'xid';
+xa rollback 'xid';
+
+xa begin 'xid';
+--connection con1
+--reap
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+--send
+alter table t force, algorithm=copy, lock=none;
+
+--connection default
+set debug_sync= 'now wait_for downgraded';
+insert into t values (3);
+set debug_sync= 'now signal goforit';
+xa end 'xid';
+xa commit 'xid' one phase;
+
+# Cleanup
+drop table t;
+set debug_sync= reset;
+
 --echo #
 --echo # End of 11.2 tests
 --echo #

sql/log.cc

@@ -2329,6 +2329,8 @@ int binlog_commit(THD *thd, bool all, bool ro_1pc)
   PSI_stage_info org_stage;
   DBUG_ENTER("binlog_commit");
 
+  IF_DBUG(bool commit_online= !thd->online_alter_cache_list.empty(),);
+
   bool is_ending_transaction= ending_trans(thd, all);
   error= binlog_online_alter_end_trans(thd, all, true);
   if (error)
@@ -2340,7 +2342,7 @@ int binlog_commit(THD *thd, bool all, bool ro_1pc)
   */
   if (!cache_mngr)
   {
-    DBUG_ASSERT(WSREP(thd) ||
+    DBUG_ASSERT(WSREP(thd) || commit_online ||
                 (thd->lex->sql_command != SQLCOM_XA_PREPARE &&
                 !(thd->lex->sql_command == SQLCOM_XA_COMMIT &&
                   thd->lex->xa_opt == XA_ONE_PHASE)));
@@ -2448,7 +2450,7 @@ static int binlog_rollback(handlerton *hton, THD *thd, bool all)
   if (!cache_mngr)
   {
     DBUG_ASSERT(WSREP(thd) || rollback_online);
-    DBUG_ASSERT(thd->lex->sql_command != SQLCOM_XA_ROLLBACK);
+    DBUG_ASSERT(thd->lex->sql_command != SQLCOM_XA_ROLLBACK || rollback_online);
 
     DBUG_RETURN(0);
   }