Structurally identical events cause wrong publication to be selected for completion

[ChristofferKarlsson]

If multiple equal events of the same type and same data are published in the same transaction, and then they are all processed, the event publication registry will have about half of them not marked as completed. Even though they're actually all processed without problem.

If making the event data unique in some way, there is no problem. But I can't see any constraints about events having to be unique in the documentation.

There seems to be a race condition, and turning on the SQL trace logging, I see that multiple concurrent tasks will update the COMPLETION_DATE for the same EVENT_PUBLICATION.

2025-02-16T13:56:22.211+01:00 DEBUG 147904 --- [modulith-multiple-equal-events] [         task-4] o.s.jdbc.core.JdbcTemplate               : Executing prepared SQL statement [UPDATE EVENT_PUBLICATION
SET COMPLETION_DATE = ?
WHERE
		ID = ?
]
2025-02-16T13:56:22.211+01:00 TRACE 147904 --- [modulith-multiple-equal-events] [         task-5] o.s.jdbc.core.StatementCreatorUtils      : Setting SQL statement parameter value: column index 2, parameter value [869af431-273d-4407-b2ee-e13d3289e99d], value class [java.util.UUID], SQL type unknown
2025-02-16T13:56:22.211+01:00 TRACE 147904 --- [modulith-multiple-equal-events] [         task-3] o.s.jdbc.core.StatementCreatorUtils      : Setting SQL statement parameter value: column index 2, parameter value [869af431-273d-4407-b2ee-e13d3289e99d], value class [java.util.UUID], SQL type unknown
2025-02-16T13:56:22.211+01:00 TRACE 147904 --- [modulith-multiple-equal-events] [         task-6] o.s.jdbc.core.StatementCreatorUtils      : Setting SQL statement parameter value: column index 2, parameter value [869af431-273d-4407-b2ee-e13d3289e99d], value class [java.util.UUID], SQL type unknown

I have setup a repository that reproduces the problem in a test.

[odrotbohm]

We have previously used equals(…) when trying to find the event publication currently in progress, which indeed requires the event instances to be unique even if structurally identical. I've revised that arrangement to use object identity now to avoid this limitation. Please give the 1.4 snapshots a try. The M2 release should be out in a few days.