yarn install --production complains about missing devDependencies

[Daniel15]

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

What is the current behavior?
The package.json for Yarn itself has this devDependency:

  "devDependencies": {
    "eslint-plugin-yarn-internal": "file:scripts/eslint-rules",
  }

As part of building the distribution tarball, we run npm pack, extract the resulting tarball, run npm install --production to install just the prod dependencies, then archive the resulting files (see build-dist.sh and build-dist.ps1).

scripts/eslint-rules is only needed for dev builds and not for production builds, and we don't want to distribute it with Yarn,, so we do not copy it into the dist directory. npm install --production is fine with that, while yarn install --production complains:

λ yarn install --production
yarn install v0.15.1
[1/4] Resolving packages...
error "C:\\src\\yarn\\dist\\scripts\\eslint-rules" doesn't exist.
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.
git clone https://github.com/yarnpkg/yarn.git', modifyscripts/build-dist.ps1(on Windows) orscripts/build-dist.shto runyarn install --productionrather thannpm install --production`, watch it fail.

What is the expected behavior?
yarn install --production should ignore all issues relating to devDependencies

Please mention your node.js, yarn and operating system version.
Node.js v6.7.0
Windows 10 64-bit
Latest master of Yarn as of a few minutes ago

[sebmck]

This is intentional behaviour. devDependencies need to be discoverable so we can build up the entire dependency graph. We omit dev nodes when in production and still take them into consideration when we perform the deduping hoisting so we get consistent module positions in the graph for dev and prod.

[Daniel15]

Ahh, that makes sense. I guess we'll have to do something special when building Yarn itself. Thanks!