fix: switch to async read-write lock instead of sync mutex in call handler to try to prevent deadlock

src/call.rs

@@ -11,11 +11,9 @@ use songbird::{
     CoreEvent, Event, EventContext, EventHandler, Songbird,
     driver::{Channels, SampleRate},
 };
-use std::{
-    sync::{Arc, Mutex},
-    time::Instant,
-};
+use std::{sync::Arc, time::Instant};
 use time::UtcDateTime;
+use tokio::sync::RwLock;
 use twilight_model::id::{
     Id,
     marker::{ChannelMarker, GuildMarker, UserMarker},
@@ -31,7 +29,7 @@ struct Handler {
     guild_id: Id<GuildMarker>,
     channel_id: Id<ChannelMarker>,
 
-    known_ssrcs: Arc<Mutex<OneToManyUniqueBTreeMap<Id<UserMarker>, u32>>>,
+    known_ssrcs: Arc<RwLock<OneToManyUniqueBTreeMap<Id<UserMarker>, u32>>>,
 
     audio_channels: u16,
     audio_sample_rate: u32,
@@ -53,15 +51,15 @@ impl EventHandler for Handler {
                     let user_id = Id::new(user_id.0);
 
                     self.known_ssrcs
-                        .lock()
-                        .unwrap()
+                        .write()
+                        .await
                         .insert(user_id, speaking.ssrc);
                 }
             }
             EventContext::VoiceTick(voice_tick) => {
                 for (ssrc, voice_data) in &voice_tick.speaking {
                     let user_id = {
-                        let known_ssrcs = self.known_ssrcs.lock().unwrap();
+                        let known_ssrcs = self.known_ssrcs.read().await;
                         known_ssrcs.get_left_for(ssrc).cloned()
                     };
 
@@ -126,7 +124,6 @@ impl EventHandler for Handler {
                         let channels = self.audio_channels;
                         let sample_rate = self.audio_sample_rate;
 
-
                         let recording_manager = self.recording_manager.clone();
                         let samples = pcm.clone();
 

src/heat_seek.rs

@@ -30,48 +30,53 @@ pub async fn heat_seek(state: State) {
     let mut vcs_in_guild_senders = BTreeMap::default();
 
     loop {
-        for (&guild_id, vcs_in_guild) in &*vcs_watcher.borrow() {
-            let vcs_in_guild_sender = vcs_in_guild_senders.entry(guild_id).or_insert_with(|| {
-                let (vcs_in_guild_sender, vcs_in_guild_watcher) =
-                    watch::channel(Default::default());
-                let (channel_heat_sender, channel_heat_watcher) =
-                    watch::channel(Default::default());
-                let (heat_map_sender, heat_map_watcher) = watch::channel(Default::default());
-                let (hottest_vc_sender, hottest_vc_watcher) = watch::channel(Default::default());
+        {
+            for (&guild_id, vcs_in_guild) in &*vcs_watcher.borrow() {
+                let vcs_in_guild_sender =
+                    vcs_in_guild_senders.entry(guild_id).or_insert_with(|| {
+                        let (vcs_in_guild_sender, vcs_in_guild_watcher) =
+                            watch::channel(Default::default());
+                        let (channel_heat_sender, channel_heat_watcher) =
+                            watch::channel(Default::default());
+                        let (heat_map_sender, heat_map_watcher) =
+                            watch::channel(Default::default());
+                        let (hottest_vc_sender, hottest_vc_watcher) =
+                            watch::channel(Default::default());
 
-                tokio::spawn(
-                    evaluate_heat()
-                        .bot_manager(state.bot_manager.clone())
-                        .bot_owner_user_id(state.discord_bot_owner_user_id)
-                        .bot_user_id(state.discord_user_id)
-                        .cancellation_token(state.cancellation_token.clone())
-                        .channel_heat_sender(channel_heat_sender)
-                        .vcs_in_guild_watcher(vcs_in_guild_watcher)
-                        .call(),
-                );
-                tokio::spawn(
-                    map_heat()
-                        .cancellation_token(state.cancellation_token.clone())
-                        .channel_heat_watcher(channel_heat_watcher)
-                        .heat_map_sender(heat_map_sender)
-                        .call(),
-                );
-                tokio::spawn(
-                    track_hottest_vc()
-                        .cancellation_token(state.cancellation_token.clone())
-                        .heat_map_watcher(heat_map_watcher)
-                        .hottest_vc_sender(hottest_vc_sender)
-                        .call(),
-                );
-                tokio::spawn(follow_hottest_vc(
-                    state.clone(),
-                    guild_id,
-                    hottest_vc_watcher,
-                ));
+                        tokio::spawn(
+                            evaluate_heat()
+                                .bot_manager(state.bot_manager.clone())
+                                .bot_owner_user_id(state.discord_bot_owner_user_id)
+                                .bot_user_id(state.discord_user_id)
+                                .cancellation_token(state.cancellation_token.clone())
+                                .channel_heat_sender(channel_heat_sender)
+                                .vcs_in_guild_watcher(vcs_in_guild_watcher)
+                                .call(),
+                        );
+                        tokio::spawn(
+                            map_heat()
+                                .cancellation_token(state.cancellation_token.clone())
+                                .channel_heat_watcher(channel_heat_watcher)
+                                .heat_map_sender(heat_map_sender)
+                                .call(),
+                        );
+                        tokio::spawn(
+                            track_hottest_vc()
+                                .cancellation_token(state.cancellation_token.clone())
+                                .heat_map_watcher(heat_map_watcher)
+                                .hottest_vc_sender(hottest_vc_sender)
+                                .call(),
+                        );
+                        tokio::spawn(follow_hottest_vc(
+                            state.clone(),
+                            guild_id,
+                            hottest_vc_watcher,
+                        ));
 
-                vcs_in_guild_sender
-            });
-            vcs_in_guild_sender.send_replace(Arc::new(vcs_in_guild.clone()));
+                        vcs_in_guild_sender
+                    });
+                vcs_in_guild_sender.send_replace(Arc::new(vcs_in_guild.clone()));
+            }
         }
 
         if matches!(