do not ever actually try to rmdir /

When preserveRoot is set to false, we may remove all the children of
the root directory, but we'll never actually succeed in rmdir()-ing the
root dir itself, so don't try.

lib/rimraf-posix.js

@@ -14,7 +14,7 @@ const {
   },
 } = require('./fs.js')
 
-const { resolve } = require('path')
+const { resolve, parse } = require('path')
 
 const {
   readdirOrError,
@@ -38,6 +38,12 @@ const rimrafPosix = async (path, opt) => {
   await Promise.all(entries.map(entry =>
     rimrafPosix(resolve(path, entry), opt)))
 
+  // we don't ever ACTUALLY try to unlink /, because that can never work
+  // but when preserveRoot is false, we could be operating on it.
+  // No need to check if preserveRoot is not false.
+  if (opt.preserveRoot === false && path === parse(path).root)
+    return
+
   return ignoreENOENT(rmdir(path))
 }
 
@@ -52,6 +58,10 @@ const rimrafPosixSync = (path, opt) => {
   }
   for (const entry of entries)
     rimrafPosixSync(resolve(path, entry), opt)
+
+  if (opt.preserveRoot === false && path === parse(path).root)
+    return
+
   return ignoreENOENTSync(() => rmdirSync(path))
 }
 

lib/rimraf-windows.js

@@ -9,7 +9,7 @@
 // This works around the fact that unlink/rmdir is non-atomic and takes
 // a non-deterministic amount of time to complete.
 
-const { resolve, basename } = require('path')
+const { resolve, basename, parse } = require('path')
 const { defaultTmp, defaultTmpSync } = require('./default-tmp.js')
 
 const {
@@ -75,7 +75,7 @@ const rimrafWindows = async (path, opt) => {
   if (!opt.tmp)
     return rimrafWindows(path, { ...opt, tmp: await defaultTmp(path) })
 
-  if (path === opt.tmp)
+  if (path === opt.tmp && parse(path).root !== path)
     throw new Error('cannot delete temp directory used for deletion')
 
   const entries = await readdirOrError(path)
@@ -92,6 +92,12 @@ const rimrafWindows = async (path, opt) => {
   await Promise.all(entries.map(entry =>
     rimrafWindows(resolve(path, entry), opt)))
 
+  // we don't ever ACTUALLY try to unlink /, because that can never work
+  // but when preserveRoot is false, we could be operating on it.
+  // No need to check if preserveRoot is not false.
+  if (opt.preserveRoot === false && path === parse(path).root)
+    return
+
   return await ignoreENOENT(tmpUnlink(path, opt.tmp, rmdir))
 }
 
@@ -105,7 +111,7 @@ const rimrafWindowsSync = (path, opt) => {
   if (!opt.tmp)
     return rimrafWindowsSync(path, { ...opt, tmp: defaultTmpSync(path) })
 
-  if (path === opt.tmp)
+  if (path === opt.tmp && parse(path).root !== path)
     throw new Error('cannot delete temp directory used for deletion')
 
   const entries = readdirOrErrorSync(path)
@@ -123,6 +129,9 @@ const rimrafWindowsSync = (path, opt) => {
   for (const entry of entries)
     rimrafWindowsSync(resolve(path, entry), opt)
 
+  if (opt.preserveRoot === false && path === parse(path).root)
+    return
+
   return ignoreENOENTSync(() => tmpUnlinkSync(path, opt.tmp, rmdirSync))
 }
 

test/rimraf-posix.js

@@ -170,3 +170,32 @@ t.test('ignore ENOENTs from unlink/rmdir', async t => {
 
   t.end()
 })
+
+t.test('rimraffing root, do not actually rmdir root', async t => {
+  let ROOT = null
+  const { parse } = require('path')
+  const { rimrafPosix, rimrafPosixSync } = t.mock('../lib/rimraf-posix.js', {
+    path: {
+      ...require('path'),
+      parse: (path) => {
+        const p = parse(path)
+        if (path === ROOT)
+          p.root = path
+        return p
+      },
+    },
+  })
+  t.test('async', async t => {
+    ROOT = t.testdir(fixture)
+    await rimrafPosix(ROOT, { preserveRoot: false })
+    t.equal(fs.statSync(ROOT).isDirectory(), true, 'root still present')
+    t.same(fs.readdirSync(ROOT), [], 'entries all gone')
+  })
+  t.test('sync', async t => {
+    ROOT = t.testdir(fixture)
+    rimrafPosixSync(ROOT, { preserveRoot: false })
+    t.equal(fs.statSync(ROOT).isDirectory(), true, 'root still present')
+    t.same(fs.readdirSync(ROOT), [], 'entries all gone')
+  })
+  t.end()
+})

test/rimraf-windows.js

@@ -449,3 +449,36 @@ t.test('handle EPERMs, chmod raises something other than ENOENT', async t => {
   })
   t.end()
 })
+
+t.test('rimraffing root, do not actually rmdir root', async t => {
+  const fs = require('../lib/fs.js')
+  let ROOT = null
+  const { parse } = require('path')
+  const {
+    rimrafWindows,
+    rimrafWindowsSync,
+  } = t.mock('../lib/rimraf-windows.js', {
+    path: {
+      ...require('path'),
+      parse: (path) => {
+        const p = parse(path)
+        if (path === ROOT)
+          p.root = path
+        return p
+      },
+    },
+  })
+  t.test('async', async t => {
+    ROOT = t.testdir(fixture)
+    await rimrafWindows(ROOT, { preserveRoot: false })
+    t.equal(fs.statSync(ROOT).isDirectory(), true, 'root still present')
+    t.same(fs.readdirSync(ROOT), [], 'entries all gone')
+  })
+  t.test('sync', async t => {
+    ROOT = t.testdir(fixture)
+    rimrafWindowsSync(ROOT, { preserveRoot: false })
+    t.equal(fs.statSync(ROOT).isDirectory(), true, 'root still present')
+    t.same(fs.readdirSync(ROOT), [], 'entries all gone')
+  })
+  t.end()
+})