From d8a7d014ae022f159ddfe461865c291164fe2700 Mon Sep 17 00:00:00 2001
From: Sinabina <sinabina@Sinabinas-MacBook-Pro-4.local>
Date: Fri, 10 Jul 2026 16:31:24 -0700
Subject: [PATCH] fix(browse): preserve live daemon during busy loads

---
 browse/src/cli.ts                            | 37 ++++++++++++++------
 browse/test/live-daemon-preservation.test.ts | 18 ++++++++++
 2 files changed, 44 insertions(+), 11 deletions(-)
 create mode 100644 browse/test/live-daemon-preservation.test.ts

diff --git a/browse/src/cli.ts b/browse/src/cli.ts
index 59327b7923..b1d41b13b2 100644
--- a/browse/src/cli.ts
+++ b/browse/src/cli.ts
@@ -89,7 +89,7 @@ if (IS_WINDOWS && !NODE_SERVER_SCRIPT) {
   );
 }
 
-interface ServerState {
+export interface ServerState {
   pid: number;
   port: number;
   token: string;
@@ -105,6 +105,16 @@ interface ServerState {
   xvfbDisplay?: string;
 }
 
+/** A daemon whose process still exists may be busy even when HTTP health checks
+ * time out. Preserve it (and its browser session) instead of guessing that it
+ * is dead. The caller can retry once the current page load settles. */
+export function shouldPreserveUnresponsiveServer(
+  state: ServerState | null,
+  processAlive: (pid: number) => boolean = isProcessAlive,
+): boolean {
+  return !!state?.pid && processAlive(state.pid);
+}
+
 // ─── State File ────────────────────────────────────────────────
 function readState(): ServerState | null {
   try {
@@ -451,12 +461,14 @@ async function ensureServer(flags?: GlobalFlags): Promise<ServerState> {
     process.exit(1);
   }
 
-  // Guard: never silently replace a headed server with a headless one.
-  // Headed mode means a user-visible Chrome window is (or was) controlled.
-  // Silently replacing it would be confusing — tell the user to reconnect.
-  if (state && state.mode === 'headed' && isProcessAlive(state.pid)) {
-    console.error(`[browse] Headed server running (PID ${state.pid}) but not responding.`);
-    console.error(`[browse] Run '/open-gstack-browser' to restart.`);
+  // A live daemon can stop answering HTTP while Chromium finishes a heavy
+  // navigation. Restarting here destroys tabs, cookies, and login state. Only
+  // auto-restart after the daemon process itself is demonstrably gone.
+  if (shouldPreserveUnresponsiveServer(state)) {
+    console.error(`[browse] Server running (PID ${state!.pid}) but not responding — busy, not restarting.`);
+    console.error(state!.mode === 'headed'
+      ? `[browse] Retry shortly, or run '/open-gstack-browser' to restart intentionally.`
+      : '[browse] Retry shortly, or run `browse disconnect` to restart intentionally.');
     process.exit(1);
   }
 
@@ -590,10 +602,13 @@ async function sendCommand(state: ServerState, command: string, args: string[],
       // can briefly stop answering HTTP while still alive. Before declaring a
       // crash, if the process is alive give /health a bounded chance to recover
       // and just retry the command — never kill+restart a live-but-busy server.
-      if (oldState?.pid && isProcessAlive(oldState.pid) && await probeHealthWithBackoff(oldState.port)) {
-        if (retries >= 1) throw new Error('[browse] Server unresponsive after retry — aborting');
-        console.error('[browse] Server was briefly unresponsive (busy); retrying command...');
-        return sendCommand(oldState, command, args, retries + 1);
+      if (shouldPreserveUnresponsiveServer(oldState)) {
+        if (await probeHealthWithBackoff(oldState!.port)) {
+          if (retries >= 1) throw new Error('[browse] Server unresponsive after retry — aborting');
+          console.error('[browse] Server was briefly unresponsive (busy); retrying command...');
+          return sendCommand(oldState!, command, args, retries + 1);
+        }
+        throw new Error('[browse] Server is still running but unresponsive — busy, not restarting. Retry shortly.');
       }
       // Truly dead (or health never recovered) → restart.
       if (retries >= 1) throw new Error('[browse] Server crashed twice in a row — aborting');
diff --git a/browse/test/live-daemon-preservation.test.ts b/browse/test/live-daemon-preservation.test.ts
new file mode 100644
index 0000000000..c74bfb7443
--- /dev/null
+++ b/browse/test/live-daemon-preservation.test.ts
@@ -0,0 +1,18 @@
+import { describe, expect, test } from 'bun:test';
+import { shouldPreserveUnresponsiveServer, type ServerState } from '../src/cli';
+
+const state = { pid: 42 } as ServerState;
+
+describe('live daemon preservation (#2219)', () => {
+  test('preserves an unresponsive daemon while its process is alive', () => {
+    expect(shouldPreserveUnresponsiveServer(state, pid => pid === 42)).toBe(true);
+  });
+
+  test('allows restart after the daemon process is gone', () => {
+    expect(shouldPreserveUnresponsiveServer(state, () => false)).toBe(false);
+  });
+
+  test('allows startup when no prior daemon state exists', () => {
+    expect(shouldPreserveUnresponsiveServer(null, () => true)).toBe(false);
+  });
+});