Watch mode stopped working on macOS Sierra

[Anahkiasen]

This is a bug that seems to happen ever since I've updated to Sierra.

Whenever I want to run Jest in --watch mode it crashes:

$ jest --watch
2016-09-22 10:49 node[79167] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
2016-09-22 10:49 node[79167] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
2016-09-22 10:49 node[79167] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: Error watching file for changes: EMFILE
    at exports._errnoException (util.js:1036:11)
    at FSEvent.FSWatcher._handle.onchange (fs.js:1406:11)

Tried reinstalling the node modules, checking for any updates and anything. I can't seem to reproduce it on a new project but on the other hand even if I just run an empty test suite with --testPathPattern it still crashes, so I'm guessing it's a dependency conflict somewhere. I don't have any setup files or anything, it's literally running an empty file and crashing.

I don't get any more output with --debug so not sure what else to provide to help. This does not happen with --watchman

$ node --version && npm --version && jest --version
v6.6.0
3.10.8
v15.1.1

[robzolkos]

I had the same issue. Upgrading watchman with brew install watchman to v4.7.0 fixed it.

[cpojer]

I'm quite confident this is not a Jest issue but either an underlying module or something else on your system. Unsure how to troubleshoot, everything is fine here on Sierra.

[gaearon]

I also got a similar report about Sierra: facebook/create-react-app#713

[gaearon]

@cpojer Do you have a Sierra? Have you tried 6.6.0 on it?

[gaearon]

Per facebook/create-react-app#713 (comment), uninstalling Watchman fixes the issue so it’s either a problem with Watchman, or its Jest integration on Sierra.

[gaearon]

A few other possibly related threads:

ember-cli/ember-cli#6259
facebook/watchman#358

Can you try any suggestions there and report back?

[cpojer]

@gaearon I'm using node 6.6.0 on Sierra with watchman and everything is fine.

[cpojer]

Definitely seems like a watchman/upgrading issue. I'm gonna close this out for now but happy to reopen in case this is actually a Jest problem. Since many people reported this on other projects (rn) it is unlikely though.

[gnoff]

I do not believe I have ever had watchman installed and I just now am experiencing this issue with jest in watch mode. I also recently upgraded to macOS Sierra. My guess is watchman can help (and I will try it as a workaround) but I don't think the problem is native to having or using watchman

[bedeoverend]

FWIW I don't have watchman installed and still had this bug, but deleting my node_modules folder and reinstall did the trick for me

[hmeerlo]

I think it is a bit short through the corner to close this issue. Jest reports an error, so maybe the problem is in one of the dependencies which need to be updated? I removed my node_modules and reinstalled, but to no avail. I never installed watchman and even if I did, the dependencies should be coming from my package.json, not from any external program I installed.

[cpojer]

I was thinking that fsevents is the issue. I would recommend reinstalling the node binary, wiping away all node_modules folders and doing a fresh npm install.

[hmeerlo]

I installed new node binary (6.7.0), removed node_modules again, reinstalled everything but still the same error. But I guess the problem is that it is trying to watch too many files at once: http://stackoverflow.com/questions/8965606/node-and-error-emfile-too-many-open-files