chore(windows): instrument detached daemon launch

packages/desktop/src/daemon/daemon-manager.ts

@@ -1,5 +1,5 @@
 import { spawn, type ChildProcess } from "node:child_process";
-import { existsSync, readFileSync } from "node:fs";
+import { appendFileSync, existsSync, readFileSync } from "node:fs";
 import path from "node:path";
 import { app, ipcMain } from "electron";
 import { loadConfig, resolvePaseoHome, getOrCreateServerId } from "@getpaseo/server";
@@ -27,6 +27,7 @@ const STOP_TIMEOUT_MS = 15_000;
 const KILL_TIMEOUT_MS = 3_000;
 const DETACHED_STARTUP_GRACE_MS = 1200;
 const DEFAULT_ELECTRON_DEV_SERVER_URL = "http://localhost:8081";
+const DAEMON_LAUNCH_LOG_FILENAME = "daemon-launch.log";
 
 type DesktopDaemonState = "starting" | "running" | "stopped" | "errored";
 
@@ -75,6 +76,10 @@ function logFilePath(): string {
   return path.join(getPaseoHome(), DAEMON_LOG_FILENAME);
 }
 
+function launchLogFilePath(): string {
+  return path.join(getPaseoHome(), DAEMON_LAUNCH_LOG_FILENAME);
+}
+
 function isProcessRunning(pid: number): boolean {
   try {
     process.kill(pid, 0);
@@ -140,6 +145,24 @@ function tailFile(filePath: string, lines = 50): string {
   }
 }
 
+function appendLaunchLog(message: string, details?: Record<string, unknown>): void {
+  const line = [
+    new Date().toISOString(),
+    "[desktop daemon]",
+    `pid=${process.pid}`,
+    message,
+    details ? JSON.stringify(details) : "",
+  ]
+    .filter((part) => part.length > 0)
+    .join(" ");
+
+  try {
+    appendFileSync(launchLogFilePath(), `${line}\n`, "utf-8");
+  } catch {
+    // Keep launch debugging best-effort so desktop startup behavior is unchanged.
+  }
+}
+
 function buildDesktopDaemonCorsOriginsEnv(): string | undefined {
   const origins = new Set(
     (process.env.PASEO_CORS_ORIGINS ?? "")
@@ -303,6 +326,16 @@ async function startDaemon(): Promise<DesktopDaemonStatus> {
     },
   });
 
+  appendLaunchLog("starting detached daemon", {
+    appIsPackaged: app.isPackaged,
+    daemonRunnerEntry: daemonRunner.entryPath,
+    daemonRunnerExecArgv: daemonRunner.execArgv,
+    command: invocation.command,
+    args: invocation.args,
+    listen: process.env.PASEO_LISTEN ?? null,
+    corsOrigins: corsOrigins ?? null,
+  });
+
   const child: ChildProcess = spawn(
     invocation.command,
     invocation.args,
@@ -313,6 +346,12 @@ async function startDaemon(): Promise<DesktopDaemonStatus> {
     },
   );
 
+  appendLaunchLog("detached spawn returned", {
+    childPid: child.pid ?? null,
+    spawnfile: child.spawnfile,
+    spawnargs: child.spawnargs,
+  });
+
   child.unref();
 
   // Wait for process to survive the grace period
@@ -327,15 +366,26 @@ async function startDaemon(): Promise<DesktopDaemonStatus> {
     const timer = setTimeout(() => finish(false), DETACHED_STARTUP_GRACE_MS);
 
     child.once("error", () => {
+      appendLaunchLog("detached child emitted error during grace period", {
+        childPid: child.pid ?? null,
+      });
       clearTimeout(timer);
       finish(true);
     });
     child.once("exit", () => {
+      appendLaunchLog("detached child emitted exit during grace period", {
+        childPid: child.pid ?? null,
+      });
       clearTimeout(timer);
       finish(true);
     });
   });
 
+  appendLaunchLog("detached startup grace period completed", {
+    childPid: child.pid ?? null,
+    exitedEarly,
+  });
+
   if (exitedEarly) {
     const logs = tailFile(logFilePath(), 15);
     throw new Error(`Daemon failed to start.${logs ? `\n\nRecent logs:\n${logs}` : ""}`);
@@ -344,6 +394,15 @@ async function startDaemon(): Promise<DesktopDaemonStatus> {
   // Poll for PID file with server ID
   for (let attempt = 0; attempt < STARTUP_POLL_MAX_ATTEMPTS; attempt++) {
     const status = resolveStatus();
+    if (attempt === 0 || attempt === STARTUP_POLL_MAX_ATTEMPTS - 1 || attempt % 10 === 9) {
+      appendLaunchLog("polling daemon status after detached start", {
+        attempt: attempt + 1,
+        status: status.status,
+        pid: status.pid,
+        listen: status.listen,
+        serverId: status.serverId || null,
+      });
+    }
     if (status.status === "running" && status.serverId) return status;
     await sleep(STARTUP_POLL_INTERVAL_MS);
   }