fix: handle Windows with .cmd/.ps1 shims and add tests

- Extract ensureAliasLinks to its own module for testability
- On Windows, create .cmd and .ps1 shims instead of symlinks
- On Unix, create symlinks (as before)
- Skip alias creation when targets don't exist (pnpm v10)
- Add vitest and 8 tests covering unix/windows/skip/no-overwrite

src/install-pnpm/ensureAliasLinks.test.ts

@@ -0,0 +1,145 @@
+import { describe, it, expect, beforeEach } from 'vitest'
+import { ensureAliasLinks } from './ensureAliasLinks'
+import { mkdtemp, mkdir, writeFile, readFile, readlink } from 'fs/promises'
+import { existsSync } from 'fs'
+import path from 'path'
+import os from 'os'
+
+async function createTempDir (): Promise<string> {
+  return mkdtemp(path.join(os.tmpdir(), 'alias-links-test-'))
+}
+
+async function setupStandaloneFixture (binDir: string): Promise<void> {
+  const exeDir = path.join(binDir, '..', '@pnpm', 'exe')
+  await mkdir(exeDir, { recursive: true })
+  await writeFile(path.join(exeDir, 'pn'), '#!/bin/sh\necho pn\n', { mode: 0o755 })
+  await writeFile(path.join(exeDir, 'pnpx'), '#!/bin/sh\necho pnpx\n', { mode: 0o755 })
+  await writeFile(path.join(exeDir, 'pnx'), '#!/bin/sh\necho pnx\n', { mode: 0o755 })
+}
+
+async function setupNonStandaloneFixture (binDir: string): Promise<void> {
+  const pnpmBinDir = path.join(binDir, '..', 'pnpm', 'bin')
+  await mkdir(pnpmBinDir, { recursive: true })
+  await writeFile(path.join(pnpmBinDir, 'pnpm.cjs'), 'console.log("pnpm")\n')
+  await writeFile(path.join(pnpmBinDir, 'pnpx.cjs'), 'console.log("pnpx")\n')
+}
+
+describe('ensureAliasLinks', () => {
+  let binDir: string
+
+  beforeEach(async () => {
+    const tmpDir = await createTempDir()
+    binDir = path.join(tmpDir, 'node_modules', '.bin')
+    await mkdir(binDir, { recursive: true })
+  })
+
+  describe('standalone mode', () => {
+    it('creates symlinks on unix when targets exist', async () => {
+      await setupStandaloneFixture(binDir)
+
+      await ensureAliasLinks(binDir, true, 'linux')
+
+      expect(existsSync(path.join(binDir, 'pn'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pnpx'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pnx'))).toBe(true)
+
+      const pnTarget = await readlink(path.join(binDir, 'pn'))
+      expect(pnTarget).toBe(path.join('..', '@pnpm', 'exe', 'pn'))
+    })
+
+    it('creates .cmd and .ps1 shims on windows when targets exist', async () => {
+      await setupStandaloneFixture(binDir)
+
+      await ensureAliasLinks(binDir, true, 'win32')
+
+      // Should create .cmd shims, not extensionless symlinks
+      expect(existsSync(path.join(binDir, 'pn.cmd'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pnx.cmd'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pn.ps1'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pnx.ps1'))).toBe(true)
+
+      // Should not create extensionless symlinks on windows
+      expect(existsSync(path.join(binDir, 'pn'))).toBe(false)
+      expect(existsSync(path.join(binDir, 'pnx'))).toBe(false)
+
+      const cmdContent = await readFile(path.join(binDir, 'pn.cmd'), 'utf8')
+      expect(cmdContent).toContain(path.join('..', '@pnpm', 'exe', 'pn'))
+      expect(cmdContent).toContain('%*')
+
+      const ps1Content = await readFile(path.join(binDir, 'pn.ps1'), 'utf8')
+      expect(ps1Content).toContain(path.join('..', '@pnpm', 'exe', 'pn'))
+      expect(ps1Content).toContain('@args')
+    })
+  })
+
+  describe('non-standalone mode', () => {
+    it('creates symlinks on unix when targets exist', async () => {
+      await setupNonStandaloneFixture(binDir)
+
+      await ensureAliasLinks(binDir, false, 'linux')
+
+      expect(existsSync(path.join(binDir, 'pn'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pnpx'))).toBe(true)
+      expect(existsSync(path.join(binDir, 'pnx'))).toBe(true)
+
+      const pnTarget = await readlink(path.join(binDir, 'pn'))
+      expect(pnTarget).toBe(path.join('..', 'pnpm', 'bin', 'pnpm.cjs'))
+
+      // pnx should point to pnpx.cjs (same as pnpx)
+      const pnxTarget = await readlink(path.join(binDir, 'pnx'))
+      expect(pnxTarget).toBe(path.join('..', 'pnpm', 'bin', 'pnpx.cjs'))
+    })
+
+    it('creates .cmd shims on windows when targets exist', async () => {
+      await setupNonStandaloneFixture(binDir)
+
+      await ensureAliasLinks(binDir, false, 'win32')
+
+      expect(existsSync(path.join(binDir, 'pn.cmd'))).toBe(true)
+
+      const cmdContent = await readFile(path.join(binDir, 'pn.cmd'), 'utf8')
+      expect(cmdContent).toContain(path.join('..', 'pnpm', 'bin', 'pnpm.cjs'))
+    })
+  })
+
+  describe('skips when targets do not exist', () => {
+    it('creates no links when target directory is empty (v10)', async () => {
+      // Don't create any fixture files — simulates pnpm v10 without aliases
+
+      await ensureAliasLinks(binDir, true, 'linux')
+
+      expect(existsSync(path.join(binDir, 'pn'))).toBe(false)
+      expect(existsSync(path.join(binDir, 'pnpx'))).toBe(false)
+      expect(existsSync(path.join(binDir, 'pnx'))).toBe(false)
+    })
+
+    it('creates no shims on windows when targets do not exist', async () => {
+      await ensureAliasLinks(binDir, true, 'win32')
+
+      expect(existsSync(path.join(binDir, 'pn.cmd'))).toBe(false)
+      expect(existsSync(path.join(binDir, 'pnx.cmd'))).toBe(false)
+    })
+  })
+
+  describe('does not overwrite existing links', () => {
+    it('preserves existing symlinks on unix', async () => {
+      await setupStandaloneFixture(binDir)
+      await writeFile(path.join(binDir, 'pn'), 'existing content')
+
+      await ensureAliasLinks(binDir, true, 'linux')
+
+      const content = await readFile(path.join(binDir, 'pn'), 'utf8')
+      expect(content).toBe('existing content')
+    })
+
+    it('preserves existing .cmd shims on windows', async () => {
+      await setupStandaloneFixture(binDir)
+      await writeFile(path.join(binDir, 'pn.cmd'), 'existing shim')
+
+      await ensureAliasLinks(binDir, true, 'win32')
+
+      const content = await readFile(path.join(binDir, 'pn.cmd'), 'utf8')
+      expect(content).toBe('existing shim')
+    })
+  })
+})