Handle unexpected disconnects via packets (#1521)

src/client/voice/ClientVoiceManager.js

@@ -1,4 +1,5 @@
 const Collection = require('../../util/Collection');
+const Constants = require('../../util/Constants');
 const VoiceConnection = require('./VoiceConnection');
 const { Error } = require('../../errors');
 
@@ -31,10 +32,13 @@ class ClientVoiceManager {
 
   onVoiceStateUpdate({ guild_id, session_id, channel_id }) {
     const connection = this.connections.get(guild_id);
-    if (connection) {
-      connection.channel = this.client.channels.get(channel_id);
-      connection.setSessionID(session_id);
+    if (!connection) return;
+    if (!channel_id && connection.status !== Constants.VoiceStatus.DISCONNECTED) {
+      connection._disconnect();
+      return;
     }
+    connection.channel = this.client.channels.get(channel_id);
+    connection.setSessionID(session_id);
   }
 
   /**

src/client/voice/VoiceConnection.js

@@ -307,7 +307,14 @@ class VoiceConnection extends EventEmitter {
     this.sendVoiceStateUpdate({
       channel_id: null,
     });
-    this.player.destroy();
+    this._disconnect();
+  }
+
+  /**
+   * Internally disconnects (doesn't send disconnect packet.)
+   * @private
+   */
+  _disconnect() {
     this.cleanup();
     this.status = Constants.VoiceStatus.DISCONNECTED;
     /**
@@ -317,11 +324,14 @@ class VoiceConnection extends EventEmitter {
     this.emit('disconnect');
   }
 
+
   /**
    * Cleans up after disconnect.
    * @private
    */
   cleanup() {
+    this.player.destroy();
+
     const { ws, udp } = this.sockets;
 
     if (ws) {