Errors from optionalDependency installation scripts should be ignored

[chuwik]

Do you want to request a feature or report a bug?
Bug, for compatibility with npm

What is the current behavior?
If an optionalDependency install script fails, the whole 'yarn install' fails.
With npm client, these errors are ignored and the install succeeds.

If the current behavior is a bug, please provide the steps to reproduce.
The sinopia npm package has an optionalDependency on fs-ext, whose install script fails in Windows. This is a known issue, but since it is optional the errors get ignored with 'npm install'; but fails with 'yarn'.

In a Windows machine:
yarn add sinopia

This happens even if ignore-optional=true.
If ignore-scripts=true, error goes away.

What is the expected behavior?
'yarn install' prints out the errors, but the installation succeeds.

Please mention your node.js, yarn and operating system version.
node.js 6.7.0
yarn 0.15.1
Windows 10

[johnhaley81]

Related npm bug for packages that use shrinkwrap npm/npm#12698

[liatreis]

+1 this is preventing us from using yarn as a drop-in replacement for npm.

[mvestergaard]

This is also keeping my team back from switching to yarn.

[diwu1989]

+1 need this one to be fixed too

[GvRillaer]

+1 me too