Start script hangs without error when there are no available inotify watches

[trygveaa]

Description

I tried to run npm start in a new project (i.e. I ran the four commands under "Quick Overview"), and it hanged indefinitely (well, at least for several minutes until I aborted) after the output "Starting packager...".

Running react-native start gave the error ERROR watch {path} ENOSPC, which made me realize that there were no available inotify watches.

After increasing fs.inotify.max_user_watches, npm start started and ran normally.

Expected Behavior

npm start should give a warning or exit with an error saying that there are no available watches, so it can't start.

Observed Behavior

npm start hanged with this output, and never continued:

$ npm start

> [email protected] start /home/trygve/dev/create-react-native-app/my-app
> react-native-scripts start

13.49.26: Starting packager...

Environment

Please run these commands in the project folder and fill in their results:

• npm ls react-native-scripts: [email protected]
• npm ls react-native: [email protected]
• npm ls expo: [email protected]
• node -v: v7.10.0
• npm -v: 4.6.1
• yarn --version: 0.24.6
• watchman version: Not installed

Also specify:

1. Operating system: Arch Linux
2. Phone/emulator/simulator & version: Not relevant

Reproducible Demo

Ran npm start in a clean project just created, so nothing to provide here.

[k3a]

@Tetralix On Linux do "sudo sysctl -w fs.inotify.max_user_watches=10000". This changes kernel sysctl value. This is temporary until reboot. To make it permanent, add fs.inotify.max_user_watches=10000 to a file in /etc/sysctl.d directory or /etc/sysctl.conf depending on distro.

[luffs]

Spent hours googling, reinstalling, upgrading, downgrading, switching to yarn until I found this issue. Thank you!

+1 to have an error message...

Used this guide to increase the inotify watchers max amount:
https://github.com/guard/listen/wiki/Increasing-the-amount-of-inotify-watchers

[cyan33]

FYI, I ran into the same issue again, but fixed with running

sudo sysctl -w kern.maxfiles=5242880
sudo sysctl -w kern.maxfilesperproc=524288

I think it would be weird and confusing to come across this error at very beginning. And it would not hurt to mention this in an obvious position of the document, rather than in this issue.

ADMIN EDIT: these commands work for Mac only.

[jsstrn]

To solve this issue, just install Watchman via Homebrew (for macOS) with:

$ brew update
$ brew install watchman

Source: Watchman docs. For other operating systems, refer to their docs.

[cwervo]

Just ran into this issue. Agreed with the above commenters that something like:

On MacOS run:

    $ brew install watchman

should be added to the error message. Of course adding other relevant information for other OS's as well. Pretty bad developer experience to have to come to this GH issue & skim to find out what I needed to do just to run the example setup.

[geoffreywiseman]

Maybe just include a URL to watchman -- no sense providing install instructions as they vary by platform and could be subject to change, no sense coupling CRNA to the installation instructions for watchman IMO.

e.g.

6:55:12 p.m.: Unable to start server
For more information:  https://git.io/v5vcn
To resolve, either install watchman:  https://git.io/vxGX7
Or run the following snippet:
  sudo sysctl -w kern.maxfiles=5242880
  sudo sysctl -w kern.maxfilesperproc=524288

[willxy]

OSX; ran into same thing, had to read the entire thread to find out what "install watchman" means and that it doesn't mean npm, agree with comments that it should at least point to the watchman website, although having it suggest "brew install watchman" would be by far the most helpful.

[anp]

@willxy you're right! Since this issue is apparently showing up in search results for lots of people, I decided to lock this and to hide all comments that don't contain important information for fixing the issue. Hopefully it should be much easier to read the history now. If after installing watchman (NOT using the watchman npm package) and raising inotify/fsevents limits you're still having issues, please open a new issue! Thanks.