From 49ec53f4aed15887bf36cc2135ce8ec41ae9f0b8 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Sat, 20 Dec 2025 18:39:02 +0100
Subject: [PATCH] fix: detect main module under PM2

---
 src/index.ts              |  6 ++--
 src/infra/is-main.test.ts | 38 +++++++++++++++++++++++
 src/infra/is-main.ts      | 63 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 2 deletions(-)
 create mode 100644 src/infra/is-main.test.ts
 create mode 100644 src/infra/is-main.ts

diff --git a/src/index.ts b/src/index.ts
index 24df05eac..2dbedba63 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -17,6 +17,7 @@ import {
   saveSessionStore,
 } from "./config/sessions.js";
 import { ensureBinary } from "./infra/binaries.js";
+import { isMainModule } from "./infra/is-main.js";
 import { ensureClawdisCliOnPath } from "./infra/path-env.js";
 import {
   describePortOwner,
@@ -68,8 +69,9 @@ export {
   waitForever,
 };
 
-const isMain =
-  process.argv[1] && fileURLToPath(import.meta.url) === process.argv[1];
+const isMain = isMainModule({
+  currentFile: fileURLToPath(import.meta.url),
+});
 
 if (isMain) {
   // Global error handlers to prevent silent crashes from unhandled rejections/exceptions.
diff --git a/src/infra/is-main.test.ts b/src/infra/is-main.test.ts
new file mode 100644
index 000000000..c54a1d681
--- /dev/null
+++ b/src/infra/is-main.test.ts
@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest";
+
+import { isMainModule } from "./is-main.js";
+
+describe("isMainModule", () => {
+  it("returns true when argv[1] matches current file", () => {
+    expect(
+      isMainModule({
+        currentFile: "/repo/dist/index.js",
+        argv: ["node", "/repo/dist/index.js"],
+        cwd: "/repo",
+        env: {},
+      }),
+    ).toBe(true);
+  });
+
+  it("returns true under PM2 when pm_exec_path matches current file", () => {
+    expect(
+      isMainModule({
+        currentFile: "/repo/dist/index.js",
+        argv: ["node", "/pm2/lib/ProcessContainerFork.js"],
+        cwd: "/repo",
+        env: { pm_exec_path: "/repo/dist/index.js", pm_id: "0" },
+      }),
+    ).toBe(true);
+  });
+
+  it("returns false when running under PM2 but this module is imported", () => {
+    expect(
+      isMainModule({
+        currentFile: "/repo/node_modules/clawdis/dist/index.js",
+        argv: ["node", "/repo/app.js"],
+        cwd: "/repo",
+        env: { pm_exec_path: "/repo/app.js", pm_id: "0" },
+      }),
+    ).toBe(false);
+  });
+});
diff --git a/src/infra/is-main.ts b/src/infra/is-main.ts
new file mode 100644
index 000000000..0c753f019
--- /dev/null
+++ b/src/infra/is-main.ts
@@ -0,0 +1,63 @@
+import fs from "node:fs";
+import path from "node:path";
+
+type IsMainModuleOptions = {
+  currentFile: string;
+  argv?: string[];
+  env?: NodeJS.ProcessEnv;
+  cwd?: string;
+};
+
+function normalizePathCandidate(
+  candidate: string | undefined,
+  cwd: string,
+): string | undefined {
+  if (!candidate) return undefined;
+
+  const resolved = path.resolve(cwd, candidate);
+  try {
+    return fs.realpathSync.native(resolved);
+  } catch {
+    return resolved;
+  }
+}
+
+export function isMainModule({
+  currentFile,
+  argv = process.argv,
+  env = process.env,
+  cwd = process.cwd(),
+}: IsMainModuleOptions): boolean {
+  const normalizedCurrent = normalizePathCandidate(currentFile, cwd);
+  const normalizedArgv1 = normalizePathCandidate(argv[1], cwd);
+
+  if (
+    normalizedCurrent &&
+    normalizedArgv1 &&
+    normalizedCurrent === normalizedArgv1
+  ) {
+    return true;
+  }
+
+  // PM2 runs the script via an internal wrapper; `argv[1]` points at the wrapper.
+  // PM2 exposes the actual script path in `pm_exec_path`.
+  const normalizedPmExecPath = normalizePathCandidate(env.pm_exec_path, cwd);
+  if (
+    normalizedCurrent &&
+    normalizedPmExecPath &&
+    normalizedCurrent === normalizedPmExecPath
+  ) {
+    return true;
+  }
+
+  // Fallback: basename match (relative paths, symlinked bins).
+  if (
+    normalizedCurrent &&
+    normalizedArgv1 &&
+    path.basename(normalizedCurrent) === path.basename(normalizedArgv1)
+  ) {
+    return true;
+  }
+
+  return false;
+}