From dadeeca765f2e9c6a55294941e25c1773149a357 Mon Sep 17 00:00:00 2001
From: Brennan Benson <79079362+brennanb2025@users.noreply.github.com>
Date: Thu, 27 Aug 2026 18:25:36 -0700
Subject: [PATCH] fix(relay): use safe process runner for inspection

---
 .../pty-child-process-inspection.test.ts      | 60 +++++++++++++++++++
 src/relay/pty-child-process-inspection.ts     | 21 +++----
 2 files changed, 71 insertions(+), 10 deletions(-)
 create mode 100644 src/relay/pty-child-process-inspection.test.ts

diff --git a/src/relay/pty-child-process-inspection.test.ts b/src/relay/pty-child-process-inspection.test.ts
new file mode 100644
index 00000000000..e164fdff086
--- /dev/null
+++ b/src/relay/pty-child-process-inspection.test.ts
@@ -0,0 +1,60 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { inspectProcessChildren } from './pty-child-process-inspection'
+import { runProcess } from '../shared/child-process/run-process'
+
+vi.mock('../shared/child-process/run-process', () => ({ runProcess: vi.fn() }))
+
+const result = (overrides: Partial<Awaited<ReturnType<typeof runProcess>>> = {}) => ({
+  code: 0,
+  signal: null,
+  stdout: '42\n',
+  stderr: '',
+  timedOut: false,
+  ...overrides
+})
+
+describe('inspectProcessChildren', () => {
+  beforeEach(() => vi.mocked(runProcess).mockReset())
+
+  it('reports children only from successful pgrep output', async () => {
+    vi.mocked(runProcess).mockResolvedValue(result())
+
+    await expect(inspectProcessChildren(41)).resolves.toEqual({ hasChildProcesses: true })
+    expect(runProcess).toHaveBeenCalledWith({
+      program: 'pgrep',
+      args: ['-P', '41'],
+      timeoutMs: 3000
+    })
+  })
+
+  it('reports no children only from the pgrep no-match exit', async () => {
+    vi.mocked(runProcess).mockResolvedValue(result({ code: 1, stdout: '' }))
+
+    await expect(inspectProcessChildren(41)).resolves.toEqual({ hasChildProcesses: false })
+  })
+
+  it.each([
+    result({ code: 0, stdout: '' }),
+    result({ code: 2, stdout: '' }),
+    result({ code: null, signal: 'SIGTERM', stdout: '' }),
+    result({ code: 1, stdout: '', timedOut: true })
+  ])('marks degraded process reads unavailable', async (processResult) => {
+    vi.mocked(runProcess).mockResolvedValue(processResult)
+
+    await expect(inspectProcessChildren(41)).resolves.toEqual({
+      hasChildProcesses: false,
+      unavailable: true
+    })
+  })
+
+  it('marks spawn failures unavailable', async () => {
+    vi.mocked(runProcess).mockImplementationOnce(() => {
+      throw new Error('pgrep missing')
+    })
+
+    await expect(inspectProcessChildren(41)).resolves.toEqual({
+      hasChildProcesses: false,
+      unavailable: true
+    })
+  })
+})
diff --git a/src/relay/pty-child-process-inspection.ts b/src/relay/pty-child-process-inspection.ts
index 6184911b5e0..4994849be7b 100644
--- a/src/relay/pty-child-process-inspection.ts
+++ b/src/relay/pty-child-process-inspection.ts
@@ -1,22 +1,23 @@
-import { execFile as execFileCb } from 'node:child_process'
-import { promisify } from 'node:util'
-
-const execFile = promisify(execFileCb)
+import { runProcess } from '../shared/child-process/run-process'
 
 export async function inspectProcessChildren(pid: number): Promise<{
   hasChildProcesses: boolean
   unavailable?: true
 }> {
   try {
-    const { stdout } = await execFile('pgrep', ['-P', String(pid)], {
-      encoding: 'utf-8',
-      timeout: 3000
+    const result = await runProcess({
+      program: 'pgrep',
+      args: ['-P', String(pid)],
+      timeoutMs: 3000
     })
-    return { hasChildProcesses: stdout.trim().length > 0 }
-  } catch (error) {
-    if ((error as { code?: string | number }).code === 1) {
+    if (result.code === 0 && result.stdout.trim().length > 0) {
+      return { hasChildProcesses: true }
+    }
+    if (result.code === 1 && !result.timedOut) {
       return { hasChildProcesses: false }
     }
     return { hasChildProcesses: false, unavailable: true }
+  } catch {
+    return { hasChildProcesses: false, unavailable: true }
   }
 }