Tag prefetched copies with the controller's run token

If the controller crashes after sending generation N but before saving it, the destination keeps that prefetch while the controller restarts at N-1, and another instance can then upload different data as generation N. The controller now picks a random token per run, sends it with every prefetch and acquire reply, and the scenario applies a held copy only when its generation and token both match, and lets a new run's copy replace one with another token.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

plugins/player_sync/test/instance.js

@@ -5,7 +5,7 @@ import * as lib from "@clusterio/lib";
 
 import * as mock from "../../../test/mock.js";
 import loadInstancePlugin, { recipeNotificationDelta, applyRecipeNotificationDelta } from "../dist/node/instance.js";
-import { DownloadResponse, PrefetchEvent } from "../dist/node/messages.js";
+import { AcquireResponse, DownloadResponse, PrefetchEvent } from "../dist/node/messages.js";
 import { components } from "../dist/node/components.js";
 import { plugin as info } from "../dist/node/index.js";
 
@@ -271,13 +271,13 @@ describe("player_sync", function() {
 			}
 		});
 
-		const prefetch = playerData => mock.getHandler(instance, PrefetchEvent)(new PrefetchEvent(playerData));
+		const prefetch = playerData => mock.getHandler(instance, PrefetchEvent)(new PrefetchEvent(playerData, "tok"));
 		function prefetchCommands(playerData, enabled = Object.keys(components)) {
 			const chunks = JSON.stringify(playerData).match(/.{1,10}/g);
 			const sent = lib.escapeString(JSON.stringify(Object.fromEntries(enabled.map(c => [c, true]))));
 			return chunks.map((chunk, i) => "/sc player_sync.prefetch_inventory(" +
 				`'test',${playerData.generation},'${lib.escapeString(chunk)}',${i + 1},${chunks.length}` +
-				`${i === 0 ? `,'${sent}'` : ""})`);
+				`${i === 0 ? `,'${sent}','tok'` : ""})`);
 		}
 
 		it("should send prefetch_inventory chunks with the generation and the full recipe list", async function() {
@@ -296,6 +296,12 @@ describe("player_sync", function() {
 			assert.ok(commands.length > 1, "more than one chunk");
 			assert.deepEqual(instance.server.rconCommands, commands);
 		});
+		it("should send the token with the first chunk only", async function() {
+			await prefetch({ generation: 3, name: "test" });
+			const commands = instance.server.rconCommands;
+			assert.ok(commands[0].endsWith(",'tok')"));
+			assert.ok(commands.slice(1).every(command => !command.includes("tok")));
+		});
 		it("should stop when the save refuses the first chunk", async function() {
 			const playerData = { generation: 3, name: "test" };
 			const commands = prefetchCommands(playerData);
@@ -312,4 +318,22 @@ describe("player_sync", function() {
 			assert.deepEqual(instance.server.rconCommands, commands.slice(0, 2));
 		});
 	});
+
+	describe("acquire reply", function() {
+		it("should pass the controller's token to acquire_response", async function() {
+			try {
+				lib.registerPluginMessages([info]);
+			} catch (err) {
+				// Already registered by the full test suite
+			}
+			const { instance, host } = await mock.loadInstancePlugin(loadInstancePlugin, info);
+			host.connector.connected = true;
+			instance.sendTo = async () => new AcquireResponse("acquired", 4, true, undefined, undefined, "tok");
+			instance.server.emit("ipc-player_sync_acquire", { player_name: "test" });
+			await lib.wait(10);
+			const [command] = instance.server.rconCommands;
+			assert.ok(command.startsWith("/sc player_sync.acquire_response("), command);
+			assert.ok(command.includes(lib.escapeString('"token":"tok"')), command);
+		});
+	});
 });