Don't over-redact events

[jaller94]

Fixes #430.

[Half-Shot]

How is this one looking?

[jaller94]

Rick asked me to not mess with the database but query the current state of the Matrix event before redacting it.
I don't know how to ask a Matrix server, if an event has been redacted by another event.

[Half-Shot]

Ugh, short answer is you cannot. But since the loop comes from the slack side we could surely delete the event_id from the DB when we get a redaction from matrix so it won't be possible to over-redact?

[jaller94]

That is what I had started to implement here, before I got told to try checking the redaction.
Will continue with the "delete the event from the DB" route on Monday.

[Half-Shot]

Code change looks sensible if it works :)

[jaller94]

Current state

• From Matrix; redacted on Slack – "deleted by Slack Bridge" on Matrix
• From Matrix; redacted on Matrix – works
• From Slack; redacted on Slack – still visible on Matrix
• From Slack; redacted on Matrix – still visible on Slack; over-redacted on Matrix

EDIT: Which - for me - is the same state as on develop.

[Half-Shot]

Yeah, that's concerning.

From Matrix; redacted on Slack – "deleted by Slack Bridge" on Matrix should really be mapping to the person who deleted it, not the bridge bot.

From Slack; redacted on Slack – still visible on Matrix is particularly problematic because that's an easy one in theory to solve.

From Slack; redacted on Matrix – still visible on Slack; over-redacted on Matrix is also bad because it obscures the redactor, also I would have expected deleting from the DB to solve this.

[Half-Shot]

sounds like it's solved.