Deleting an empty directory triggers `error` instead of `unlinkDir`

[npetruzzelli]

When deleting an empty directory, I get an unexpected error event. If the same directory has any kind of content (other than empty directories), the expected unlinkDir event is triggered without an error.

• OS: Windows 10 Pro
• node: 4.3.1
• npm: 3.7.3
• I'm using glob-watcher (3.0.0), which gives me a chokidar (1.6.1) instance.

The console output:

events.js:141
      throw er; // Unhandled 'error' event
      ^

Error: watch null EPERM
    at exports._errnoException (util.js:870:11)
    at FSEvent.FSWatcher._handle.onchange (fs.js:1217:21)

The directory is deleted by selecting it in Windows Explorer and pressing delete.

Is this a bug? or the expected behavior I need to account for with the error event?

[es128]

What gets emitted on the raw event in this scenario?

[es128]

Also, is the watcher directly on this directory or a parent? Are you using glob patterns?

[npetruzzelli]

var watcher = globWatcher('local_packages/**/*');
watcher.on('raw', function(event, path, details){
    console.log('Raw event info:', event, path, details);
});
// => Raw event info: rename New folder { watchedPath: 'local_packages' }

[npetruzzelli]

New folder is a child of local_packages

[es128]

And if you add a noop error event listener, you still do not get an unlinkDir event? Or you just aren't seeing it because the lack of an error listener causes node to throw?

[es128]

The code at

chokidar/lib/nodefs-handler.js

Lines 89 to 99 in f17186d

	watcher.on('error', function(error) {
	// Workaround for https://github.com/joyent/node/issues/4337
	if (process.platform === 'win32' && error.code === 'EPERM') {
	fs.open(path, 'r', function(err, fd) {
	if (fd) fs.close(fd);
	if (!err) broadcastErr(error);
	});
	} else {
	broadcastErr(error);
	}
	});

is intended to suppress the sort of error you're describing, so we have to narrow down where it's actually coming from.

[npetruzzelli]

The noop prevents the error from throwing, but the error still happens (confirmed by logging it). the unlinkDir event still does not happen.

[es128]

How does it behave with the ignorePermissionErrors: true option?

[npetruzzelli]

No error event, but also no unlinkDir event. Raw output hasn't changed.

[es128]

It does seem like a bug, for which a PR is welcome.

Unfortunately I do not have a Windows environment presently available with which to try to reproduce and debug this.

[npetruzzelli]

I don't know if I have the time/skill to solve it, but I will at least give it a try starting with the code you highlighted. What I am working on is a personal project, which unfortunately is lower on the priority list.

Alternatively, there are some free virtual machines available, but I don't know if they have enough capabilities for node as they are meant for browser testing: https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/ . It might be worth a shot, depending on your host OS.

[es128]

Yes, I've used stuff like that before, but working with them is kind of a hassle, and I'm at a point where I'd rather encourage more community participation.

[npetruzzelli]

chokidar/lib/nodefs-handler.js

Line 94 in f17186d

if (!err) broadcastErr(error);

// => fd === 3;
// => err === null

Additional References:

• util.js 870:11
• fs.js 1217:21

I've run into something that is even more confusing. I've added a couple log statements.

    watcher.on('error', function(error) {
// console.log('   ERROR:', error);
      // Workaround for https://github.com/joyent/node/issues/4337
      if (process.platform === 'win32' && error.code === 'EPERM') {
        fs.open(path, 'r', function(err, fd) {
console.log('     ERR:', err);
          if (fd) fs.close(fd);
          if (!err) broadcastErr(error);
        });
      } else {
        broadcastErr(error);
      }
    });

As is we get the following:

     ERR: null

but simply un-commenting the first console.log statement causes a different result:

   ERROR: { [Error: watch null EPERM]
  code: 'EPERM',
  errno: 'EPERM',
  syscall: 'watch null',
  filename: null }
Raw event info: rename New folder { watchedPath: 'local_packages' }
     ERR: { [Error: ENOENT: no such file or directory, open 'P:\projects\project-name\local_packages\New folder']
  errno: -4058,
  code: 'ENOENT',
  syscall: 'open',
  path: 'P:\\projects\\project-name\\local_packages\\New folder' }

Since err is not null, the error event isn't triggered. That still leaves unlinkDir not being triggered. This behavior is just bizarre. Simply logging error shouldn't change err unless the difference in milliseconds it takes to output the log allowed something to finish on the file system.

console.log( fs.statSync(path).isDirectory() );
        fs.open(path, 'r', function(err, fd) {

// => true

Using the async version (fs.stat(path)) also returns true. For whatever reason, it looks like it isn't done being deleted, despite the filename given to the error (in fs.js) being null. Could this be used to our advantage in this case? if err == null && stat.isDirectory() === true then trigger the unlinkDir event? Or could this be too unreliable?

This is about as far as I can get for now. If I can free up more time, I'll try doing more digging, but it may well be above my current skill level.

[ScorpioCoding]

Got The Same issue

What versions of npm and node are you using?

node v7.7.1
npm 4.1.2

What OS are you using?

Microsoft Windows 10 Pro x64
Version	10.0.14393 Build 14393

My gulpfile.js code

var gulp = require('gulp');
var chokidar = require('chokidar');

gulp.task('event', function(){
  var watcher = chokidar.watch('src/**/*',{
    ignored: /(^|[\/\\])\../,
    persistent: true
  });
  var log = console.log.bind(console);
  watcher
    .on('add', path => log(`File ${path} has been added`))
    .on('change', path => log(`File ${path} has been changed`))
    .on('unlink', path => log(`File ${path} has been removed`))
    .on('addDir', path => log(`Directory ${path} has been added`))
    .on('unlinkDir', path => log(`Directory ${path} has been removed`))
    .on('error', error => log(`Watcher error: ${error}`))
    .on('ready', () => log('Initial scan complete. Ready for changes'))
    .on('raw', (event, path, details) => {
      log('Raw event info:', event, path, details);
    });
});

gulp.task('default', ['event']);

Testing

Testing in different Editors and using windows explore

.Atom -v1.14.4 x64
.VScode -v1.10.1

Testing sequence of events
So in my root directory I have the directory "src" upon the watcher is watching for any changes
Then I add the folder 'jump' and in my powershell I get the following response

Initial scan complete. Ready for changes
Raw event info: rename jump { watchedPath: 'src' }
Directory src\jump has been added

So when I delete the folder 'jump' the response is

Initial scan complete. Ready for changes
Raw event info: rename jump { watchedPath: 'src' }
Directory src\jump has been added
Watcher error: Error: Error watching file for changes: EPERM
Raw event info: rename jump { watchedPath: 'src' }

Testing without the .on('raw') section gives the following error

Error: Error watching file for changes: EPERM
at exports._errnoException (util.js:1029:11)
at FSEvent.FSWatcher._handle.onchange (fs.js:1375:11)

Questions

1. What is wrong ?
2. What am I doing wrong ?
3. What can I do about it?
4. Can someone fix my code sample so I can see what I 'm doing wrong and learn from it?