1397224 - Heroku deployments failing during yarn build with "EROFS: read-only file system, access '/usr/local/bin'"

Status: RESOLVED FIXED

(Tree Management :: Treeherder: Infrastructure, defect, P1)

Description

[Ed Morley [:emorley]]

For example:
https://dashboard.heroku.com/apps/treeherder-stage/activity/builds/ec63f24f-7f6c-4cd7-b3d2-224a3dda6da4

"""
-----> Running post-compile hook

yarn build v1.0.0

$ ./node_modules/neutrino/bin/neutrino build --presets ./neutrino-custom/production.js

error An unexpected error occurred: "EROFS: read-only file system, access '/usr/local/bin'".
"""

Comment 1

[Ed Morley [:emorley]]

This is caused by the Heroku nodeje buildpack defaulting to the latest yarn release (even including release candidates), combined with there being a bug in the newly released yarn 1.0.0 release candidate:
https://github.com/heroku/heroku-buildpack-nodejs/issues/468#issuecomment-327430350

Yarn have a fix in progress:
https://github.com/yarnpkg/yarn/pull/4322

And in the meantime we can pin to a specific older version of yarn, using eg:

  "engines": {
    "yarn": "0.28.4"
  },

For now I'll wait to see how long the yarn fix takes, otherwise I'll land the version pinning change.

Comment 2

[Ed Morley [:emorley]]

The Heroku nodejs maintainer created a test branch with a workaround, which I confirmed fixed the issue by performing a test push to treeherder-stage using a custom buildpack setting:
https://github.com/heroku/heroku-buildpack-nodejs/issues/468#issuecomment-327495467

...and has now been merged to master / deployed under the stable `heroku/nodejs` alias. 

I've reset the buildpacks setting for treeherder-stage, so we're all done here.