From 101886e5222a5ec4f1edacf68557a479485967cb Mon Sep 17 00:00:00 2001
From: Cooldude2606 <25043174+Cooldude2606@users.noreply.github.com>
Date: Sun, 8 Mar 2026 17:52:35 +0000
Subject: [PATCH 1/2] Downgrade error to a warning as it does not prevent
 server startup.

---
 packages/host/src/server.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/host/src/server.ts b/packages/host/src/server.ts
index 6152fee6..86cfdfaf 100644
--- a/packages/host/src/server.ts
+++ b/packages/host/src/server.ts
@@ -887,7 +887,7 @@ export class FactorioServer extends events.EventEmitter<FactorioServerEvents> {
 		try {
 			this._whitelistWatcher = fs.watch(filePath);
 		} catch (err: any) {
-			this._logger.error(`Unable to watch whitelist, bidirectional sync will not be available:\n${err}`);
+			this._logger.warn(`Unable to watch whitelist, bidirectional sync will not be available:\n${err}`);
 			return;
 		}
 

From 5b5b2c28f73c24064d9288e20d6054a790b44b49 Mon Sep 17 00:00:00 2001
From: Cooldude2606 <25043174+Cooldude2606@users.noreply.github.com>
Date: Sun, 8 Mar 2026 18:34:21 +0000
Subject: [PATCH 2/2] Always write a whitelist on server start

---
 packages/host/src/Instance.ts | 11 +++++++++++
 test/integration/instance.js  | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/packages/host/src/Instance.ts b/packages/host/src/Instance.ts
index 952470be..67951204 100644
--- a/packages/host/src/Instance.ts
+++ b/packages/host/src/Instance.ts
@@ -866,6 +866,17 @@ end`.replace(/\r?\n/g, " ");
 				this.server.writePath("server-whitelist.json"),
 				JSON.stringify([...this._host.whitelist], null, "\t")
 			);
+		} else {
+			// Always create the whitelist even if unused
+			// This allows it to be watched for changes without a server restart
+			try {
+				// wx will throw an error if the file already exists to prevent overwrite
+				await fs.writeFile(this.server.writePath("server-whitelist.json"), "\n[]\n", { flag: "wx" });
+			} catch (err: any) {
+				if (err.code !== "EEXIST") {
+					throw err;
+				}
+			}
 		}
 
 		await this.syncMods();
diff --git a/test/integration/instance.js b/test/integration/instance.js
index 2955e001..7cba7de8 100644
--- a/test/integration/instance.js
+++ b/test/integration/instance.js
@@ -1,11 +1,13 @@
 "use strict";
+const path = require("path");
 const assert = require("assert").strict;
 const lib = require("@clusterio/lib");
+const fs = require("fs-extra");
 
 const { testMatrix } = require("../common");
 const {
 	slowTest, exec, execCtl, execCtlProcess, sendRcon, getControl,
-	requiresFactorio, hasFactorio,
+	requiresFactorio, hasFactorio, instancesDir,
 } = require("./index");
 
 const instId = 48;
@@ -67,6 +69,32 @@ describe("Clusterio Instance", function() {
 		await execCtl(`instance stop ${instAltName}`);
 		await execCtl(`instance delete ${instAltName}`);
 	});
+	describe("whitelist creation", function() {
+		const whitelistPath = path.join(instancesDir, instName, "server-whitelist.json");
+		before(async function() {
+			this.timeout(20000);
+			await execCtl(`${instSetConfig} factorio.sync_whitelist disabled`);
+			await execCtl(`${instSetConfig} factorio.enable_whitelist false`);
+		});
+		afterEach(async function() {
+			this.timeout(20000);
+			await execCtl(`instance stop ${instName}`);
+		});
+		it("should always create a whitelist json even if unused", async function() {
+			slowTest(this);
+			await fs.remove(whitelistPath);
+			await execCtl(`instance start ${instName}`);
+			const whitelist = await fs.readJSON(whitelistPath);
+			assert.deepEqual(whitelist, []);
+		});
+		it("should not overwrite the existing whitelist if sync is disabled", async function() {
+			slowTest(this);
+			await fs.writeJSON(whitelistPath, ["test_user"]);
+			await execCtl(`instance start ${instName}`);
+			const whitelist = await fs.readJSON(whitelistPath);
+			assert.deepEqual(whitelist, ["test_user"]);
+		});
+	});
 	for (const [savePatchingEnabled, scriptCommandsEnabled] of testMatrix([true, false], [true, false])) {
 		const strSavePatching = `save patching: ${savePatchingEnabled ? "Enabled" : "Disabled"}`;
 		const strScriptCommands = `script commands: ${scriptCommandsEnabled ? "Enabled" : "Disabled"}`;
@@ -81,6 +109,7 @@ describe("Clusterio Instance", function() {
 			before(async function() {
 				this.timeout(20000);
 				// Create and start a patched save
+				await execCtl(`${instSetConfig} factorio.enable_whitelist true`);
 				await execCtl(`${instSetConfig} factorio.enable_save_patching ${savePatchingEnabled}`);
 				await execCtl(`${instSetConfig} factorio.enable_script_commands ${scriptCommandsEnabled}`);
 				await execCtl(`instance save create ${instName}`);