Parent channel of thread has no thread manager

[Glazelf]

Which package is this bug report for?

discord.js

Issue description

Bot "randomly" (not during boot cycle) crashes with error below:

Seems to be an issue with thread parent checks or something. I talked to @almostSouji about this problem here, for some context.

Note (souji):
The issue is not reproduceable on reboot and happened only once during normal operation.

Code sample

No response

Versions

• discord.js 14.16.3

Issue priority

Low (slightly annoying)

Which partials do you have configured?

User, Channel, GuildMember, Message, Reaction

Which gateway intents are you subscribing to?

Guilds, GuildMembers, GuildModeration, GuildMessages, GuildMessageReactions, DirectMessages, MessageContent

I have tested this issue on a development release

No response

[almostSouji]

Seems to come from here:

discord.js/packages/discord.js/src/util/Channels.js

Lines 67 to 72 in 0873f9a

	case ChannelType.AnnouncementThread:
	case ChannelType.PublicThread:
	case ChannelType.PrivateThread: {
	channel = new (getThreadChannel())(guild, data, client);
	if (!allowUnknownGuild) channel.parent?.threads.cache.set(channel.id, channel);
	break;

Which would imply a channel that does not have .threads (or another value) is being set as a parent (since the .parent seems to exist) at some point in time.

Potential causes could be a corrupted cache or a private thread being created on a somewhat rare channel type, which we have not considered yet.

[almostSouji]

Looking at the partials, could this potentially be caused by the parent being partial?
So we receive the partial parent and populate the cache with it; then the thread is being constructed and the partial parent does not have the .threads?