From c81739f9f723f20ecbebb44611737c6e8887de02 Mon Sep 17 00:00:00 2001
From: Gagan <gaganp000999@gmail.com>
Date: Sat, 4 Jul 2026 17:30:55 +0530
Subject: [PATCH] =?UTF-8?q?fix(apps):=20bind=20IPv6=20loopback=20too=20?=
 =?UTF-8?q?=E2=80=94=20blank=20apps=20in-app?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

macOS's resolver maps *.apps.localhost to ::1 only, so Electron's iframe
connects to [::1]:3210 while the server listened on 127.0.0.1 only —
connection refused, blank app, while external browsers succeeded via their
own IPv4 fallback. Listen on both loopback addresses (::1 best-effort for
IPv6-disabled machines).
---
 apps/x/packages/core/src/apps/server.ts | 28 ++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/apps/x/packages/core/src/apps/server.ts b/apps/x/packages/core/src/apps/server.ts
index f9a39785..cc58a69e 100644
--- a/apps/x/packages/core/src/apps/server.ts
+++ b/apps/x/packages/core/src/apps/server.ts
@@ -54,6 +54,11 @@ const MIME_TYPES: Record<string, string> = {
 // ---------------------------------------------------------------------------
 
 let server: Server | null = null;
+// IPv6 loopback listener. REQUIRED on macOS: the OS resolver maps
+// *.apps.localhost to ::1 (only), so Electron's iframe connects to [::1]:3210 —
+// binding just 127.0.0.1 makes in-app requests fail (blank app) while external
+// browsers succeed via their own IPv4 fallback.
+let server6: Server | null = null;
 let startPromise: Promise<void> | null = null;
 let watcher: FSWatcher | null = null;
 let serverError: string | null = null;
@@ -708,8 +713,9 @@ export async function init(): Promise<void> {
         try {
             await fsp.mkdir(APPS_DIR, { recursive: true });
             await startWatcher();
+            const expressApp = createApp();
             await new Promise<void>((resolve, reject) => {
-                const s = createApp().listen(APPS_PORT, '127.0.0.1', () => {
+                const s = expressApp.listen(APPS_PORT, '127.0.0.1', () => {
                     server = s;
                     serverError = null;
                     console.log(`[Apps] server on 127.0.0.1:${APPS_PORT} (host suffix ${APPS_HOST_SUFFIX}), dir ${APPS_DIR}`);
@@ -724,6 +730,18 @@ export async function init(): Promise<void> {
                     reject(error);
                 });
             });
+            // Dual-stack loopback: also listen on ::1 (see server6 note above).
+            // Best-effort — some machines have IPv6 disabled.
+            await new Promise<void>((resolve) => {
+                const s6 = expressApp.listen(APPS_PORT, '::1', () => {
+                    server6 = s6;
+                    resolve();
+                });
+                s6.on('error', (error: NodeJS.ErrnoException) => {
+                    console.warn(`[Apps] IPv6 loopback listen failed (${error.code}); continuing IPv4-only`);
+                    resolve();
+                });
+            });
         } catch (error) {
             serverError = error instanceof Error ? error.message : String(error);
             await shutdown();
@@ -753,6 +771,14 @@ export async function shutdown(): Promise<void> {
     }
     eventClients.clear();
 
+    const s6 = server6;
+    server6 = null;
+    if (s6) {
+        await new Promise<void>((resolve) => {
+            s6.close(() => resolve());
+        });
+    }
+
     const s = server;
     server = null;
     if (!s) return;