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/controller.ts

@@ -2,6 +2,7 @@ import type { ControllerPluginContext, InstanceRecord } from "@clusterio/control
 import type { IpcPlayerData } from "./messages.js";
 import { mergePlayerData } from "./components.js";
 
+import crypto from "node:crypto";
 import fs from "node:fs/promises";
 import path from "path";
 import * as lib from "@clusterio/lib";
@@ -67,6 +68,8 @@ async function saveDatabase(
 
 export default async function(context: ControllerPluginContext) {
 	const { controller, logger, plugin } = context;
+	// Differs on every controller start: a prefetched copy holding another run's token may be one this run never saved
+	const runToken = crypto.randomBytes(8).toString("hex");
 	const acquiredPlayers = new Map<string, { instanceId: number, expiresMs?: number }>();
 	const { playerDatastore, tombstones } = await loadDatabase(controller.config, logger);
 	let playerDatastoreDirty = false;
@@ -125,7 +128,7 @@ export default async function(context: ControllerPluginContext) {
 			return;
 		}
 		try {
-			controller.sendTo({ instanceId: targetId }, new msg.PrefetchEvent(playerData));
+			controller.sendTo({ instanceId: targetId }, new msg.PrefetchEvent(playerData, runToken));
 			logger.verbose(`Prefetching ${playerData.name} to ${target.config.get("instance.name")}`);
 		} catch (err: any) {
 			// sendEvent throws when the instance's host isn't connected; the upload is stored either way
@@ -186,6 +189,7 @@ export default async function(context: ControllerPluginContext) {
 			playerDatastore.has(playerName),
 			undefined,
 			epoch || undefined,
+			runToken,
 		);
 	});