Yarn (0.22.0) fails at installing gulp-sass/node-sass in offline environment

[maelgrove]

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

Bug.

What is the current behavior?

When attempting to install gulp-sass (or node-sass respectively) in an environment without internet connection (from tarballs), the installation fails because node-sass is unable to fetch the platform binding binaries from the github repo. The node-sass install script continues by attempting to build the binaries itself, but this might fail too if certain dependencies are missing (python etc.).

This behavior is not directly related to yarn itself, but with npm, one could simply copy the necessary files from https://github.com/sass/node-sass/releases into ./node_modules/node-sass/vendor/<platform>_<version> and run npm install again.

However, when running yarn install again, yarn seems to nuke the node-sass folder completely, including the manually added file.

I also attempted to set the environment variables both in .npmrc and via cmd args as described here: https://github.com/sass/node-sass#binary-configuration-parameters, however yarn seems to completely ignore both of them (installer script still attempts to connect to the interwebs etc..)

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

1. Init fresh yarn project
2. Setup yarn offline mirror as described here: https://yarnpkg.com/lang/en/docs/offline-mirror/
3. Install node-sass (or gulp-sass)
4. Delete ./node_modules/
5. Disable internet connection
6. Attempt to install packages again w/ yarn install

What is the expected behavior?

Either...

• Yarn accepts module specific command line arguments (?)

or...

• Yarn keeps custom changes made to ./node_modules/ when running yarn install

Please mention your node.js, yarn and operating system version.

OS:        Windows 10 x64
Node.js:   6.10.2
npm:       3.10.10
yarn:      0.22.0

[ericberens]

Not ideal but you could use the --ignore-scripts flag

--ignore-scripts don't run lifecycle scripts

yarn install --ignore-scripts

then manually copy in the binaries. This may have undesired side effects if you rely on lifecycle events.

[bestander]

• Caching binary files across projects will cause other problems, e.g. sometimes binaries imprint project paths during compilation, so they can't be shared across projects.

• Making Yarn not clean node_modules is not what we want to do because we like to treat Yarn as the manager of this folder, however we can discuss some specifics

• The right way would be to make Yarn work with those gyp/sass packages that need complex install steps and allow them to be configured.
  Actually you can pass configs vai .npmrc/.yarnrc to the install scripts https://github.com/yarnpkg/yarn/blob/master/src/util/execute-lifecycle-script.js#L90, it just needs to be named properly.

[saper]

The problem here that packaged .tgz files are not ABI-dependent and there is no way for the binding to say "I have produced those binary artifacts for platform X, please package them in".

[maelgrove]

@bestander

Would it be possibilty to provide a flag for yarn install for the second option, causing yarn not to remove modified files?

[bestander]

@maelgrove, everything is possible.
But adding more flags for more use cases is not the right way to do it, this makes Yarn more complex and harder to maintain.
Feel free to help the project and invest some time to making it right.

[BYK]

Closing in favor of #3642.