Bug Report: Altering an unknown table in OnlineDDL hangs migration in queued state without proper error message

[shlomi-noach]

Overview of the Issue

If you submit an OnlineDDL ALTER TABLE for a table which is either nonexistent, or is not-up-to-date, the migration hangs in migration_status: queued even though it is terminally failed.

Reproduction Steps

Try to ALTER a non-existent table:

$ vtctldclient ApplySchema --ddl-strategy="vitess" --sql "alter table nonexistent engine=innodb" commerce
2d1740eb_6bef_11ee_8738_0a43f95f28a3

> show vitess_migrations like '2d1740eb_6bef_11ee_8738_0a43f95f28a3'\G

*************************** 1. row ***************************
                             id: 2
                 migration_uuid: 2d1740eb_6bef_11ee_8738_0a43f95f28a3
                       keyspace: commerce
                          shard: 0
                   mysql_schema: vt_commerce
                    mysql_table: nonexistent
            migration_statement: alter table nonexistent engine innodb
                       strategy: vitess
                        options:
                added_timestamp: 2023-10-16 06:42:29
            requested_timestamp: 2023-10-16 06:42:29
                ready_timestamp: NULL
              started_timestamp: NULL
             liveness_timestamp: NULL
            completed_timestamp: NULL
              cleanup_timestamp: NULL
               migration_status: queued
...

In the tablet logs:

E1016 06:42:30.303656 3401575 executor.go:3861] Table 'vt_commerce.nonexistent' doesn't exist (errno 1146) (sqlstate 42S02) during query: SHOW CREATE TABLE `nonexistent`
in Executor.getCreateTableStatement()
in Executor.analyzeSpecialAlterPlan(), uuid=2d1740eb_6bef_11ee_8738_0a43f95f28a3, table=nonexistent

Binary Version

18

Operating System and Environment details

-

Log Fragments

No response