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

> my-app@0.1.0 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: react-native-scripts@0.0.30
• npm ls react-native: react-native@0.44.2
• npm ls expo: expo@17.0.0
• 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.

[brentvatne]

It seems pretty reasonable to handle this error with a useful message as you described, as well as, of course, to not hang but to instead show some useful information and exit instead. If anyone is interested in contributing, this is a useful place to look: https://github.com/react-community/create-react-native-app/blob/master/react-native-scripts/src/util/packager.js#L55

[nimir]

I've the start script also hanging without error but seems for a different reason as i've already increased my inotify watchers and running react-native start works fine without a problem!

Same project was starting fine yesterday, no changes and it's not working today! My connection seems fine!

Environment:

• npm ls react-native-scripts: react-native-scripts@0.0.31
• npm ls react-native: react-native@0.44.3
• npm ls expo: expo@17.0.0
• node -v: v6.9.5
• npm -v: 5.0.3
• yarn --version: Not installed
• watchman version: 4.7.0

Also tried:

• rm -rf node_modules then fresh npm install
• watchman watch-del-all
• npm start --clear-cache and npm start --reset-cache

How can i debug this to find what's causing the issue? tried to look at the packager.js and scripts/start.js for verbose flags without luck!

[thinq4yourself]

👍 on this 20 day old issue. First go at CRNA for our new app with latest and this happens to us, too.

[k3a]

Confirming the issue, seen it too and it's pretty bad bug because it affects newcomers - I've created a new empty React native project and it simply hang on "Starting packager...". Confirming increase of that sysctl fixed the issue.

@nimir : try this in your project root if you haven't tried yet: ./node_modules/.bin/react-native start

[s417-lama]

I had the same issue on Ubuntu 16.04.
Try to install watchman.
If you get some error about watchman when running npm start, see: #51

[igor-levkov]

@k3a Can you please provide more details how "increase of that sysctl" fixed this issue?

[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.

[igor-levkov]

@k3a I would never figure out that problem is related to user watches parameter. Worked for me, but increased to 12k. OS: Fedora 25

[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

[penniath]

Thanks @k3a, you saved my day!

[akshaynaik404]

I had the same issue on Ubuntu 16.04.2 LTS. As @s417-lama mentioned #51 contains the solution that worked for me.

But this bug is very frustrating for beginners and should be given priority. @dikaiosune has already taken a note of this. I hope this gets fixed soon.

[ashishrvtech]

@k3a It works thanks!!!