Left guilds remain in the cache during sharding reconnection

[vakiliner]

Which package is this bug report for?

discord.js

Issue description

During sharding reconnection, if the bot leaves the guild, the guild will remain in the cache when the session is resumed.
I discovered this bug back on February 27, 2026, but because I was using my library, I only fixed this bug for myself.

Steps:

1. Wait for the ClientReady event
2. Turn off the Internet
3. Remove the app from the guild
4. Turn on the Internet
5. Wait for the ClientReady event

Code sample

client.on(Events.ClientReady, (client) => {
    console.log(`Ready. ${client.guilds.cache.size} guilds`)
})
client.on(Events.GuildCreate, (guild) => {
    console.log(`Guild create ${guild.name}`)
})
client.on(Events.GuildDelete, (guild) => {
    console.log(`Guild delete ${guild.name}`)
})

Versions

Nodejs v24.15.0
Discord.js dev, see below

Issue priority

Medium (should be fixed soon)

Which partials do you have configured?

No Partials

Which gateway intents are you subscribing to?

Guilds

I have tested this issue on a development release

3d61215

[vakiliner]

discord.js/packages/discord.js/src/client/websocket/handlers/READY.js

Line 18 in 3d61215

client.expectedGuilds.add(guild.id);

Furthermore, expected guilds are not cleared before being added.
If the shard is suddenly interrupted while the client is in the WaitingForGuilds status, and then guilds that haven't yet arrived in the GuildCreate event leave, the client will be stuck in the WaitingForGuilds status, waiting for the guild the bot left.
Okay, the client won't freeze, there is a timeout, but still need to clear Set.