[ bug ] yarn install fails

[TheWolfNL]

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
When running yarn install using yarn 1.0.1 I get:

yarn install v1.0.1
$ node scripts/use-yarn.js
This project uses yarn instead of npm. Please upgrade!
See https://yarnpkg.com.
To install dependencies:
$ yarn install
To install a new package (also adds to package.json):
$ yarn add [packagename]
To upgrade a package:
$ yarn upgrade [packagename]
For more help, see https://yarnpkg.com/en/docs/usage.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.

If the current behavior is a bug, please provide the steps to reproduce.
install

curl -o- -L https://yarnpkg.com/install.sh | sh
and run
yarn install

What is the expected behavior?
that the dependencies get installed.

yarn versions v1.0.1
{ http_parser: '2.7.0',
node: '7.7.1',
v8: '5.5.372.41',
uv: '1.11.0',
zlib: '1.2.11',
ares: '1.10.1-DEV',
modules: '51',
openssl: '1.0.2k',
icu: '58.2',
unicode: '9.0',
cldr: '30.0.3',
tz: '2016j' }
✨ Done in 0.04s.

[TheWolfNL]

Installing the previous version works for me now.

curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.0.0

[BYK]

I think the project or environment you are working in is trying to determine if you are using npm or yarn and thinks the new version of yarn is actually npm. That's not something Yarn can fix :)

But if you can give more details about your environment, I may give you hints about how to get it resolved.

[TheWolfNL]

Found the problem, indeed we had a script checking whether we were using yarn.
So yarn 1.0.1 is using npm_lifecycle_script underneath?

[BYK]

#4330 was just merged after 1.0.0 that added support for this, yeah.