[BUG] Yarn --ignore-optional flag is not working

[Sh1d0w]

Do you want to request a feature or report a bug?
It's a bug.

What is the current behavior?
While doing yarn install on the freshly checked out repo here https://github.com/brave/browser-laptop
the command fails with:

yarn --ignore-optional
yarn install v0.15.1
info No lockfile found.
[1/4] Resolving packages...
warning babel@6.5.2: Babel's CLI commands have been moved from the babel package to the babel-cli package
warning mocha > glob > minimatch@0.3.0: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning flow-bin > bin-wrapper > globby > glob > minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning mocha > to-iso-string@0.0.2: to-iso-string has been deprecated, use @segment/to-iso-string instead.
warning mocha > jade@0.26.3: Jade has been renamed to pug, please install the latest version of pug instead of jade
warning font-awesome-webpack > css-loader > cssnano > css-list@0.1.3: Deprecated.
warning font-awesome-webpack > css-loader > cssnano > postcss-merge-idents > css-list@0.1.3: Deprecated.
warning electron-builder > progress-stream > through2 > xtend > object-keys@0.4.0: 
warning gulp > vinyl-fs > glob-watcher > gaze > globule > minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
warning gulp > vinyl-fs > glob-watcher > gaze > globule > glob > graceful-fs@1.2.3: graceful-fs v3.0.0 and before will fail on node releases >= v7.0. Please update to graceful-fs@^4.0.0 as soon as possible. Use 'npm ls graceful-fs' to find it in the tree.
[2/4] Fetching packages...
warning assert@0.4.9: The engine "ender" appears to be invalid.
warning appdmg@0.3.10: The platform "linux" is incompatible with this module.
info "appdmg@0.3.10" is an optional dependency and failed compatibility check. Excluding it from installation.
error macos-alias@0.2.11: The platform "linux" is incompatible with this module.
error Found incompatible module
info Visit http://yarnpkg.com/en/docs/cli/install for documentation about this command.

Yarn must not try to install packages that are not for that OS and should not fail on such cases. This deps are not defined in the package.json file. yarn --ignore-optional has no effect too.

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

1. Check out the repo (Under Linux, reproduced with Fedora 24) https://github.com/brave/browser-laptop
2. Run yarn

What is the expected behavior?
Doing npm install installs all dependencies correctly without errors.

Please mention your node.js, yarn and operating system version.
node 5.6.0
yarn 0.15.1
Fedora 24, Linux

[Jessidhia]

macos-alias is a regular (i.e. mandatory) dependency of ds-store, which is a regular dependency of appdmg, which is a regular dependency of electron-builder. electron-builder is a devdep of browser-laptop.

This is an unbroken chain of mandatory dependencies 😕

AFAICT, electron-builder should make appdmg an optionalDependency; but if it's optional and not installed, calling it with platform: 'osx' will crash at runtime.

[Sh1d0w]

Actually @Kovensky I think you are wrong. It is an optinal dependency:

https://github.com/brave/electron-builder/blob/master/package.json#L93

So I think yarn --ignore-optional just does not work .... as well as this message is wrong then:

info "appdmg@0.3.10" is an optional dependency and failed compatibility check. Excluding it from installation.

[Jessidhia]

@Sh1d0w ah, I was looking at the generated package.json inside node_modules/electron-builder, which does list it in the dependencies key.

[Sh1d0w]

@Kovensky You are right it is in the generated file. But https://github.com/brave/browser-laptop/blob/master/package.json defines dependency "electron-builder": "^2.3.1", which in its package.json does not have appdmg https://github.com/electron-userland/electron-builder/blob/master/package.json

As pointed npm install works flawlessly so it must be yarn doing something wrong.

[Sh1d0w]

As a conclusion I think that --ignore-optional is just not working so I am changing the title of the issue.

Doing npm install (installation completes successfully with warnings for optional deps)

npm WARN optional Skipping failed optional dependency /electron-builder/appdmg:
npm WARN notsup Not compatible with your operating system or architecture: appdmg@0.3.10

Doing yarn --ignore-optional (installation fails with error)

info "appdmg@0.3.10" is an optional dependency and failed compatibility check. Excluding it from installation.
error macos-alias@0.2.11: The platform "linux" is incompatible with this module.
error Found incompatible module

[Jessidhia]

The mystery, then, is why does it work on the chokidar > fsevents chain that webpack brings in.

[Sh1d0w]

@Kovensky I think it isn't it just fails before it even gets to that point.

This is npm install at the end :

npm WARN optional Skipping failed optional dependency /electron-builder/appdmg:
npm WARN notsup Not compatible with your operating system or architecture: appdmg@0.3.10
npm WARN optional Skipping failed optional dependency /chokidar/fsevents:
npm WARN notsup Not compatible with your operating system or architecture: fsevents@1.0.14

But yarn breaks too soon when it gets to the point to install appdmg (which it shouldn't because I want to skip optional deps)

[Jessidhia]

@Sh1d0w I mean, it works fine if I create a lockfile in a mac on a project that depends on webpack and then try to install it on linux -- fsevents gets skipped as an optional dependency:

warning fsevents@1.0.14: The platform "linux" is incompatible with this module.
info "fsevents@1.0.14" is an optional dependency and failed compatibility check. Excluding it from installation.

I wonder if the problem is when it has to create a lockfile?

[Sh1d0w]

@kittens Any info on this? It is pretty serious issue and blocks install of packages on OSes that have not supported packages of packages as optional deps.

[jamiebuilds]

Folding into two separate issues:

• #1233: Yarn doesn't install non-optional sub-dependencies when --ignore-optional is used and one or more other packages mark it as optional
• #1059: Errors from optionalDependency installation scripts should be ignored