TrackHandle::get_info hanging when bot is disconnected from VC

[hrolfurgylfa]

Songbird version: next branch, commit 92314a1

Rust version (rustc -V): rustc 1.81.0 (eeb90cda1 2024-09-04)

Serenity/Twilight version: Serenity v0.12.2

Description:
After manually disconnecting the bot from a voice channel and then running TrackHandle::get_info, the bot freezes until you get the bot to join the voice channel again.

Minimal reproduction bot: https://github.com/hrolfurgylfa/musicbot-rs/blob/adf6a7f4c1008382e89bc2f9642c4a9979c4c93f/src/main.rs

Steps to reproduce:

1. Run the join command.
2. Run the play command with any url.
3. Disconnect the bot from the voice channel.
4. Run the queue command, the bot doesn't respond.
5. Run the join command again, the bot now responds to the old queue command you ran previously and re-joins the channel.

[hrolfurgylfa]

There has been some discussion on Discord regarding this: https://discord.com/channels/381880193251409931/919310407569641492/1295879582809063505

[hrolfurgylfa]

For anyone else experiencing this, a workaround is to call songbird.remove when the bot gets disconnected from a voice channel.

Just create a simple disconnect handler:

pub struct TrackDisconnectNotifier {
    songbird: Arc<Songbird>,
    guild_id: GuildId,
}

impl TrackDisconnectNotifier {
    pub fn new(songbird: Arc<Songbird>, guild_id: GuildId) -> Self {
        Self { songbird, guild_id }
    }
}

#[async_trait]
impl VoiceEventHandler for TrackDisconnectNotifier {
    async fn act(&self, _ctx: &EventContext<'_>) -> Option<Event> {
        info!("Disconnected from voice channel, removing queue for guild {}", self.guild_id);
        self.songbird
            .remove(self.guild_id)
            .await
            .expect("Failed to leave voice channel on disconnect.");

        None
    }
}

And then add this event to every track when /play is run:

handler.add_global_event(
    CoreEvent::DriverDisconnect.into(),
    TrackDisconnectNotifier::new(manager.clone(), guild_id),
);