fix: preserve process.cwd() after SETLOCAL in cmd shims

lib/index.js

@@ -114,6 +114,9 @@ const writeShim_ = (from, to, prog, args, variables) => {
         // prevent "Terminate Batch Job? (Y/n)" message
         // https://github.com/npm/cli/issues/969#issuecomment-737496588
         + 'endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & '
+        // Re-cd: SETLOCAL/batch-exit restore cwd, which undoes a parent `cd`
+        // after `setlocal` (https://github.com/npm/cmd-shim/issues/69)
+        + 'cd /d "%CD%" & '
         + `set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" ${args} ${target} %*\r\n`
   } else {
     cmd = `${head}${prog} ${args} ${target} %*\r\n`

tap-snapshots/test/basic.js.test.cjs

@@ -21,7 +21,7 @@ IF EXIST "%dp0%\\node.exe" (\\r
   SET "_prog=node"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%"  "%dp0%\\from.env" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%"  "%dp0%\\from.env" %*\\r
 
 `
 
@@ -110,7 +110,7 @@ IF EXIST "%dp0%\\node.exe" (\\r
   SET "_prog=node"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" --expose_gc "%dp0%\\from.env.args" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" --expose_gc "%dp0%\\from.env.args" %*\\r
 
 `
 
@@ -200,7 +200,7 @@ IF EXIST "%dp0%\\node.exe" (\\r
   SET "_prog=node"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%"  "%dp0%\\from.env.variables" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%"  "%dp0%\\from.env.variables" %*\\r
 
 `
 
@@ -289,7 +289,7 @@ IF EXIST "%dp0%\\/usr/bin/sh.exe" (\\r
   SET "_prog=/usr/bin/sh"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%"  "%dp0%\\from.sh" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%"  "%dp0%\\from.sh" %*\\r
 
 `
 
@@ -378,7 +378,7 @@ IF EXIST "%dp0%\\/usr/bin/sh.exe" (\\r
   SET "_prog=/usr/bin/sh"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" -x "%dp0%\\from.sh.args" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" -x "%dp0%\\from.sh.args" %*\\r
 
 `
 
@@ -587,7 +587,7 @@ IF EXIST "%dp0%\\node.exe" (\\r
   SET "_prog=node"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" --flag-one --flag-two "%dp0%\\from.env.multiple.variables" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" --flag-one --flag-two "%dp0%\\from.env.multiple.variables" %*\\r
 
 `
 
@@ -735,7 +735,7 @@ IF EXIST "%dp0%\\node.exe" (\\r
   SET "_prog=node"\\r
 )\\r
 \\r
-endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" --expose_gc "%dp0%\\from.env.S" %*\\r
+endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & cd /d "%CD%" & set PATHEXT=%PATHEXT:;.JS;=;% & "%_prog%" --expose_gc "%dp0%\\from.env.S" %*\\r
 
 `
 

test/setlocal-cwd.js

@@ -0,0 +1,193 @@
+'use strict'
+
+// https://github.com/npm/cmd-shim/issues/69
+//
+// On Windows, SETLOCAL saves cwd as well as the environment. The shebang
+// shim then does `endLocal & goto #_undefined_#` so Node is not a child of
+// the batch file (no "Terminate Batch Job?"). That goto exits batch context
+// and implied-ENDLOCALs remaining frames — including a parent
+// `setlocal` + `cd` — so process.cwd() is the pre-cd directory.
+//
+// cmd.exe expands %CD% for the whole line before endLocal runs, so
+// `cd /d "%CD%"` after the goto re-applies the directory Node should see.
+
+const test = require('tap').test
+const fs = require('fs')
+const os = require('os')
+const path = require('path')
+const { spawnSync } = require('child_process')
+const cmdShim = require('..')
+
+const fixtures = path.resolve(__dirname, 'fixtures')
+
+// Issue #69 reporter's launch line (no cwd restore).
+const ISSUE69_LAUNCH =
+  'endLocal & goto #_undefined_# 2>NUL || title %COMSPEC% & "%_prog%"  "%dp0%\\aaaa.js" %*'
+
+const launchLine = (cmdText) => {
+  const line = cmdText.split(/\r?\n/).find((l) => /^endLocal\b/i.test(l))
+  return line ? line.replace(/\r$/, '') : null
+}
+
+// Percent-expand one cmd.exe line (parse-before-execute).
+const expandPercents = (line, cwd) =>
+  line.replace(/%([^%]+)%/g, (match, name) => {
+    if (name.toUpperCase() === 'CD') {
+      return cwd
+    }
+    return match
+  })
+
+// Issue pattern:
+//   test.bat: setlocal / cd <desired> / test.cmd (no CALL)
+//   test.cmd: SETLOCAL / CALL :find_dp0 / <launch line>
+// goto #_undefined_# leaves batch context; leftover SETLOCAL frames pop.
+const cwdAtNodeLaunch = (rawLaunchLine, initialCwd, desiredCwd) => {
+  const stack = []
+  let cwd = initialCwd
+
+  // parent test.bat
+  stack.push(cwd)
+  cwd = desiredCwd
+
+  // shim SETLOCAL (find_dp0 does not cd)
+  stack.push(cwd)
+
+  const expanded = expandPercents(rawLaunchLine, cwd)
+
+  const commands = expanded
+    .split(/\s*(?:\|\||&)\s*/)
+    .map((c) => c.trim())
+    .filter(Boolean)
+
+  for (const command of commands) {
+    if (/^endLocal\b/i.test(command)) {
+      if (stack.length) {
+        cwd = stack.pop()
+      }
+      continue
+    }
+    if (/^goto\s+#/.test(command)) {
+      while (stack.length) {
+        cwd = stack.pop()
+      }
+      continue
+    }
+    const cd = command.match(/^cd\s+\/d\s+"([^"]*)"$/i) ||
+      command.match(/^cd\s+\/d\s+(\S+)/i)
+    if (cd) {
+      cwd = cd[1]
+    }
+  }
+
+  return cwd
+}
+
+test('issue #69: endLocal+goto without re-cd loses a parent setlocal+cd', (t) => {
+  t.equal(
+    cwdAtNodeLaunch(ISSUE69_LAUNCH, 'C:\\Users\\reporter', 'C:\\abcdefg'),
+    'C:\\Users\\reporter',
+    'Node sees the directory from before the parent cd'
+  )
+  t.end()
+})
+
+test('issue #69: re-cd after goto keeps the parent cd', (t) => {
+  const fixed = ISSUE69_LAUNCH.replace(
+    '|| title %COMSPEC% & ',
+    '|| title %COMSPEC% & cd /d "%CD%" & '
+  )
+  t.equal(
+    cwdAtNodeLaunch(fixed, 'C:\\Users\\reporter', 'C:\\abcdefg'),
+    'C:\\abcdefg'
+  )
+  t.end()
+})
+
+test('shebang cmd shim re-cds after endLocal+goto', async (t) => {
+  const from = path.resolve(fixtures, 'from.env')
+  const to = path.resolve(fixtures, 'setlocal-cwd.shim')
+  await cmdShim(from, to)
+  const cmd = fs.readFileSync(`${to}.cmd`, 'utf8')
+  const launch = launchLine(cmd)
+
+  t.match(
+    cmd,
+    /SETLOCAL/,
+    'still uses SETLOCAL (find_dp0 / _prog isolation)'
+  )
+  t.match(
+    cmd,
+    /endLocal & goto #_undefined_# 2>NUL \|\| title %COMSPEC% & cd \/d "%CD%" & /,
+    'restores cwd on the same line, after the batch-exit goto'
+  )
+  t.ok(launch, 'has the endLocal launch line')
+  t.match(launch, /cd \/d "%CD%"/)
+  t.notMatch(
+    launch,
+    /cd \/d "%CD%" & goto /,
+    'cd must run after goto, or implied ENDLOCAL undoes it'
+  )
+  t.equal(
+    cwdAtNodeLaunch(launch, 'C:\\Users\\reporter', 'C:\\abcdefg'),
+    'C:\\abcdefg',
+    'generated launch line keeps the issue #69 parent cd'
+  )
+})
+
+test('no-shebang cmd shim does not use the endLocal goto launch', async (t) => {
+  const from = path.resolve(fixtures, 'from.exe')
+  const to = path.resolve(fixtures, 'setlocal-cwd-exe.shim')
+  await cmdShim(from, to)
+  const cmd = fs.readFileSync(`${to}.cmd`, 'utf8')
+  t.equal(launchLine(cmd), null)
+  t.notMatch(cmd, /cd \/d "%CD%"/)
+})
+
+test('Windows: parent setlocal+cd is process.cwd() through the shim', {
+  skip: process.platform !== 'win32' ? 'cmd.exe reproduction is Windows-only' : false,
+}, async (t) => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), 'cmd-shim-cwd-'))
+  t.teardown(() => fs.rmSync(root, { recursive: true, force: true }))
+
+  const desired = path.join(root, 'abcdefg')
+  fs.mkdirSync(desired)
+
+  const cwdOut = path.join(root, 'cwd.txt')
+  const from = path.join(root, 'aaaa.js')
+  fs.writeFileSync(
+    from,
+    '#!/usr/bin/env node\n' +
+      'require(\'fs\').writeFileSync(' +
+      JSON.stringify(cwdOut) +
+      ', process.cwd())\n'
+  )
+
+  const to = path.join(root, 'test')
+  await cmdShim(from, to)
+
+  const parentBat = path.join(root, 'test.bat')
+  fs.writeFileSync(
+    parentBat,
+    [
+      '@echo off',
+      'setlocal',
+      `cd /d "${desired}"`,
+      `"${to}.cmd"`,
+      'endlocal',
+      '',
+    ].join('\r\n')
+  )
+
+  const result = spawnSync(process.env.COMSPEC || 'cmd.exe', ['/c', parentBat], {
+    cwd: root,
+    encoding: 'utf8',
+    windowsHide: true,
+  })
+  t.equal(result.status, 0, result.stderr || result.stdout)
+  t.ok(fs.existsSync(cwdOut), 'aaaa.js wrote process.cwd()')
+  t.equal(
+    path.resolve(fs.readFileSync(cwdOut, 'utf8')),
+    path.resolve(desired)
+  )
+})