Applying channel message filter won't filter existing messages on old cores
Steps
- Connect to core without support for
BacklogFilterType
- Join a channel without any message filtering
- Enable message filtering for join/part/quit/nick
Expected
Backlog removes join/part/quit/nick messages.
Actual
Backlog does not update, only new messages are filtered.
Additional
This functionality was broken in the commit to fix applying filters causing backlog to not load, 58a06877.
Instead of clearing messages, selectively filtering out for cores that don't support BacklogFilterType
may be better, triggering a backlog fetch until visible if needed.