Gateway proposal: CHANNEL_LIST_UPDATE

[Phineas]

Description

CHANNEL_LIST_UPDATE would contain either an array or object mapping channel IDs to their corresponding position when channels are moved in the list, depending on how the Discord client currently holds channel state.

Why This is Needed

Currently, if you move a channel in a big guild (with a lot of channels), the gateway spams CHANNEL_UPDATE events for all channels in-between channel with position 0 and the channel position of the channel being moved. This doesn't sound like an issue at first, but for big guilds with 100+ channels, this becomes a huge issue for members of the guild. Their client becomes unresponsive for a few seconds, sometimes up to a minute, even if they don't have the guild focussed - at worst, I've had to restart my client entirely.

I'm assuming Discord performs an O(n^2) operation or similar frontend-side when receiving these objects on the frontend, maybe it even checks the permissions against your member? I'm not sure exactly - but the one thing I know is that it's slow. I've even seen my Discord gateway session crash during testing.

Alternatives Considered

I'm assuming something could be done to the actual frontend to change how CHANNEL_UPDATEs are implemented, but I feel that it wouldn't be very scalable either. CHANNEL_LIST_UPDATE would be a future proof method.

Additional Details

Here is a video of me trying to move a channel in a big guild with gateway logs on: https://www.youtube.com/watch?v=buozCwGNLZk

You should be able to see how much the client lags when sending down those gateway events.

And here is a Tweet about the issue - you can see how many people experience this: https://twitter.com/phineyes/status/1309586592881926145

[gabehassan]

I am getting this issue where my client freezes up as-well, I'm also in Tidal.

[thiccsupreme]

lol let's hope discord does something about this

[apacheli]

Slightly off-topic: Updating guild role positions seems to send multiple guild role update events well.

[AnotherZane]

Slightly off-topic: Updating guild role positions seems to send multiple guild role update events well.

Even though the max amount of roles is half that of channels, I've seen many large guilds with roles right up to the limit. It also has the same effect on the client, so it is potentially worth doing something about as well.

[NurMarvin]

Slightly off-topic: Updating guild role positions seems to send multiple guild role update events well.

I can confirm this. It sometimes even breaks role order when moving a newly created role to the top of the list.
I've especially noticed this on a 200k member server that almost always goes into an outage everytime we move a role or create a new one.

[rycao18]

Can confirm, this is a pretty large issue that significantly affects user experience

[Hona]

Any update on this? Currently any attempt at mass modifying channels (in my case the positions in separate API calls) is very detrimental to clients and what looks like the API too from what I could tell.

[RealAlphabet]

Any update on this ?