GLM

test/backpressure.test.ts

@@ -1,7 +1,4 @@
-// What a Player sheds when its socket stops draining. The guard used to read
-// `socket.conn.bufferedAmount`, which engine.io's Socket does not have, so it
-// never once ran — and had it run, it dropped the whole batch, including the
-// create/delete that handleViewAreaUpdate had already committed to having sent.
+// Slow-client backpressure: what a Player sheds when its socket stops draining.
 import { describe, it, expect, beforeEach } from 'vitest';
 import { createRequire } from 'node:module';
 
@@ -26,8 +23,7 @@ const {
 
 applyArrayPlugins();
 
-// A socket whose write buffer we control, shaped the way engine.io really nests
-// it: the byte count lives on the ws socket under the transport.
+// Shaped like engine.io: the byte count lives on the ws socket under the transport.
 class FakeSocket {
   public readonly sent: Array<{ event: string; payload: unknown }> = [];
   public readonly conn = { transport: { socket: { bufferedAmount: 0 } } };
@@ -58,15 +54,11 @@ const makePlayer = () => {
   const players = new PlayerContainer(objects, 4, 0);
   const socket = new FakeSocket();
   const player = players.createPlayer({ name: 'player' }, socket as never);
-  // The constructor already queues this player's own CreatePlayerCommand; flush
-  // it so each case starts from an empty queue.
   player.sendQueuedCommandsToClient();
   socket.sent.length = 0;
   return { player, socket };
 };
 
-// One snapshot's worth of queued traffic: the bulky repeated state, and the
-// one-shot bookkeeping that is never regenerated.
 const queueOneSnapshot = (player: ReturnType<typeof makePlayer>['player']) => {
   player.queueCommandSend(new CreateObjectsCommand([]));
   player.queueCommandSend(new DeleteObjectsCommand([1234]));
@@ -102,8 +94,6 @@ describe('slow-client backpressure', () => {
     queueOneSnapshot(player);
     player.sendQueuedCommandsToClient();
 
-    // If the guard cannot see the buffer it degrades to sending everything, so
-    // anything shed at all proves it is reading the right property.
     expect(typesIn(socket.lastBatch)).not.toContain(PropertyUpdatesForObjects.name);
   });
 
@@ -114,12 +104,8 @@ describe('slow-client backpressure', () => {
     player.sendQueuedCommandsToClient();
 
     const types = typesIn(socket.lastBatch);
-    // Repeated in full every tick — safe to drop.
     expect(types).not.toContain(PropertyUpdatesForObjects.name);
     expect(types).not.toContain(UpdateMinimap.name);
-    // One-shot. handleViewAreaUpdate has already advanced its record of what
-    // this client knows, so these are never re-derived: dropping them leaves the
-    // client permanently missing objects and holding ghosts.
     expect(types).toContain(CreateObjectsCommand.name);
     expect(types).toContain(DeleteObjectsCommand.name);
     expect(types).toContain(ServerAnnouncement.name);