Migrations restart when an exception is thrown in the Confluence Migrator Pro code

[raphj]

When the code that handles the migration job throws (because of a bug), migrations are not marked as "executed", and the job ends.

When visited, migrations that don't have a job and are not marked as executed are started (in MigrationSheet).

But when an exception is thrown there, the page is refreshed, thus restarting the migration... which will probably stumble on the same exception, thus restarting again.

I suggest converting the "executed" boolean flag to a number that describes the current state:

• 0: not executed
• 1: executed
• 2: executing
• 3: canceled
• 4: errored

and only start a migration if executed = 0. I would do it differently from the start, but only slightly and this way is backward compatible with existing migration pages.

3 (Canceled) is useful to fix #45

2 and no job means the job died, so this is an error.