Fix chanlist in nick change events

[jkhsjdhjs]

This fixes nick changes not being bridged to matrix, due to the chanlist being empty in nick change events.

Fix matrix-org/matrix-appservice-irc#1776

[jkhsjdhjs]

@tadzik friendly ping

[tadzik]

Having tested it against the IRC bridge, it doesn't seem to solve the issue – both with and without the patch the event fires in https://github.com/matrix-org/matrix-appservice-irc/blob/develop/src/irc/BridgedClient.ts#L294. It then never does anything because this.nick is set to the connection instance's nick (could be MatrixBot or one of the matrix users' ghosts).

Did it fix anything in your case? Is there any situation when this should fire but doesn't? Could you share steps to reproduce this?

[jkhsjdhjs]

That's a different event I think, can't tell exactly because I no longer have access to my dev instance, but I think this is the event that isn't triggered currently: https://github.com/matrix-org/matrix-appservice-irc/blob/7edfec7bd45cf3695904be7da3633d2e4475f90c/src/irc/IrcEventBroker.ts#L399

Or to be precise: The event handler is triggered, the nick event is emitted, but chans is empty and thus the matrix puppets aren't updated.

To reproduce you can just have an irc user (not a puppet) change their nick. The corresponding matrix puppet will not be updated.

#103 attempted to fix this previously and initially had it correct, but then committed this to fix the typecheckers complaints: 955f6d4

This commit, however, doesn't make any sense and actually breaks the state tracking, as it saves booleans instead of channel lists in the nickChannel map. This PR reverts the commit and fixes the typecheckers complaints this way: 0f1caa2

[f0x52]

This if-statement checks if chanUser is truthy, and an empty string is not.
So nick change events don't get past this check, if the user has no channel modes set (normal user).
The event still fires in matrix-appservice-irc, but with a channel list that's always empty, so nothing happens.

[f0x52]

I was able to reproduce nick changes not getting bridged properly, and this PR correctly fixes the issue by checking if the old nick was in the userlist for the channel, instead of relying on the stored usermode string being truthy (an empty string isn't).

[jkhsjdhjs]

@tadzik

[tadzik]

Okay; gave it a fresh try and experimented a bit, since it was clearly something wrong with me here :)

Turns out that for this to work, membershipLists.global.ircToMatrix.incremental needs to be enabled. In that case the patch indeed fixes the nick change problem.