`parentId` should never be null on `PublicThreadChannel`

Which package is this bug report for?

discord.js

Issue description

How it should be A PublicThreadChannel (ThreadChannel.type: ChannelType.GuildPublicThread | ChannelType.GuildNewsThread) should never have parentId === null.

How it is in DJS PublicThreadChannel.parentId and PublicThreadChannel.parent can both be null.

The problem It is not possible (to my knowledge) to safely get the parent channel of a PublicThreadChannel. There is no fetchParent(). And we cannot use <client>.channels.fetch(<thread>.parentId) because parentId can be null. How are we supposed to get the parent channel of a public thread?

Possibly related https://github.com/discordjs/discord.js/pull/8466

Code sample

async function getParentChannelId(thread: PublicThreadChannel): Promise<string> {
	return thread.parentId; // Type 'null' is not assignable to type 'string'.
}

Package version

discord.js@14.1.1

Node.js version

v16.13.2

Operating system

Windows

Priority this issue should have

Medium (should be fixed soon)

Which partials do you have configured?

No Partials

Which gateway intents are you subscribing to?

Guilds, GuildMessages

I have tested this issue on a development release

No response

[ckohen]

Again, all threads behave exactly the same in regards to parentId and parent. It doesn’t have to do with the type of thread, its where its received from

Sweepers don’t affect the types, but it can be part of a situation where parentId is null.

As for partials, discord sometimes doesn’t send full objects, to save network bandwidth for things that most people won’t need. In the past, the resolved data for a slash commadn channel option didn’t contain parent_id (raw form from discord, same field though), so that field became nullable. Now that is no longer the case, so its probably worth another look to see if parentId can ever be missing.

[ckohen]

parent is the same no matter what type of thread it is. because private threads do also belong to channels.

parent is only nullable because of the cache access. If you have the Guilds intent and don’t do funky (unsupported) stuff with limiting channel cache, in all likelihood you will never have parent: null. This is a technicality and is not followed everywhere in the lib (notably, messages), but since threads were added after it was noticed that channel cache isn’t technically guaranteed, it was decided that the types should actually be accurate.

parentId is always present so you can fetch the parent with <client>.channels.fetch(<thread>.parentId)