fix(core): fix PTY descriptor shell leak (#16773)

packages/core/src/utils/shell-utils.test.ts

@@ -20,7 +20,9 @@ import {
   initializeShellParsers,
   stripShellWrapper,
   hasRedirection,
+  resolveExecutable,
 } from './shell-utils.js';
+import path from 'node:path';
 
 const mockPlatform = vi.hoisted(() => vi.fn());
 const mockHomedir = vi.hoisted(() => vi.fn());
@@ -33,6 +35,20 @@ vi.mock('os', () => ({
   homedir: mockHomedir,
 }));
 
+const mockAccess = vi.hoisted(() => vi.fn());
+vi.mock('node:fs', () => ({
+  default: {
+    promises: {
+      access: mockAccess,
+    },
+    constants: { X_OK: 1 },
+  },
+  promises: {
+    access: mockAccess,
+  },
+  constants: { X_OK: 1 },
+}));
+
 const mockSpawnSync = vi.hoisted(() => vi.fn());
 vi.mock('node:child_process', () => ({
   spawnSync: mockSpawnSync,
@@ -463,3 +479,65 @@ describe('hasRedirection (PowerShell via mock)', () => {
     expect(hasRedirection('echo "-> arrow"')).toBe(true);
   });
 });
+
+describe('resolveExecutable', () => {
+  const originalEnv = process.env;
+
+  beforeEach(() => {
+    process.env = { ...originalEnv };
+    mockAccess.mockReset();
+  });
+
+  afterEach(() => {
+    process.env = originalEnv;
+  });
+
+  it('should return the absolute path if it exists and is executable', async () => {
+    const absPath = path.resolve('/usr/bin/git');
+    mockAccess.mockResolvedValue(undefined); // success
+    expect(await resolveExecutable(absPath)).toBe(absPath);
+    expect(mockAccess).toHaveBeenCalledWith(absPath, 1);
+  });
+
+  it('should return undefined for absolute path if it does not exist', async () => {
+    const absPath = path.resolve('/usr/bin/nonexistent');
+    mockAccess.mockRejectedValue(new Error('ENOENT'));
+    expect(await resolveExecutable(absPath)).toBeUndefined();
+  });
+
+  it('should resolve executable in PATH', async () => {
+    const binDir = path.resolve('/bin');
+    const usrBinDir = path.resolve('/usr/bin');
+    process.env['PATH'] = `${binDir}${path.delimiter}${usrBinDir}`;
+    mockPlatform.mockReturnValue('linux');
+
+    const targetPath = path.join(usrBinDir, 'ls');
+    mockAccess.mockImplementation(async (p: string) => {
+      if (p === targetPath) return undefined;
+      throw new Error('ENOENT');
+    });
+
+    expect(await resolveExecutable('ls')).toBe(targetPath);
+  });
+
+  it('should try extensions on Windows', async () => {
+    const sys32 = path.resolve('C:\\Windows\\System32');
+    process.env['PATH'] = sys32;
+    mockPlatform.mockReturnValue('win32');
+    mockAccess.mockImplementation(async (p: string) => {
+      // Use includes because on Windows path separators might differ
+      if (p.includes('cmd.exe')) return undefined;
+      throw new Error('ENOENT');
+    });
+
+    expect(await resolveExecutable('cmd')).toContain('cmd.exe');
+  });
+
+  it('should return undefined if not found in PATH', async () => {
+    process.env['PATH'] = path.resolve('/bin');
+    mockPlatform.mockReturnValue('linux');
+    mockAccess.mockRejectedValue(new Error('ENOENT'));
+
+    expect(await resolveExecutable('unknown')).toBeUndefined();
+  });
+});

packages/core/src/utils/shell-utils.ts

@@ -5,6 +5,8 @@
  */
 
 import os from 'node:os';
+import fs from 'node:fs';
+import path from 'node:path';
 import { quote } from 'shell-quote';
 import {
   spawn,
@@ -37,6 +39,35 @@ export interface ShellConfiguration {
   shell: ShellType;
 }
 
+export async function resolveExecutable(
+  exe: string,
+): Promise<string | undefined> {
+  if (path.isAbsolute(exe)) {
+    try {
+      await fs.promises.access(exe, fs.constants.X_OK);
+      return exe;
+    } catch {
+      return undefined;
+    }
+  }
+  const paths = (process.env['PATH'] || '').split(path.delimiter);
+  const extensions =
+    os.platform() === 'win32' ? ['.exe', '.cmd', '.bat', ''] : [''];
+
+  for (const p of paths) {
+    for (const ext of extensions) {
+      const fullPath = path.join(p, exe + ext);
+      try {
+        await fs.promises.access(fullPath, fs.constants.X_OK);
+        return fullPath;
+      } catch {
+        continue;
+      }
+    }
+  }
+  return undefined;
+}
+
 let bashLanguage: Language | null = null;
 let treeSitterInitialization: Promise<void> | null = null;
 let treeSitterInitializationError: Error | null = null;