[Bug]: reversing multiple follow-up block actions can fail

[eviljeff]

Follow-up from #16119

Is there an existing issue for this?

• I have searched the existing issues

What happened?

https://mozilla.sentry.io/issues/7448848020/?query=is%3Aunresolved&referrer=issue-stream

(1452, 'Cannot add or update a child row: a foreign key constraint fails (`addons_allizom_org`.`log_activity_block`, CONSTRAINT `log_activity_block_block_id_6f5144af_fk_blocklist_block_id` FOREIGN KEY (`block_id`) REFERENCES `blocklist_block` (`id`) ON DELETE RESTRI)')

My theory is the using in get_blocks_from_guids means if we attempt to unblock twice in the same transaction, then we'll be trying to delete a block that was already deleted. Which seems to be handed in the actual deletion code, but the logging function fails because the activity log is trying to fk to an already deleted block record.

What did you expect to happen?

We don't attempt to delete a block that is already deleted - or at least fail quietly.

┆Issue is synchronized with this Jira Task

[eviljeff]

Fwiw, this kind of error is hard to pick up with CI or local testing because we don't typically use database replicas.