Add outside-collaborators to internal forks.

[JeroenKnoops]

Use-case

GitHub has released a features which allows enterprise to fork internally.

This is great, because now we can fork a repository and add specific outside-collaborators to the fork only, shielding off the internal conversations and only sync major releases to the downstream.

The Problem

Unfortunately GitHub does not allow you to add outside-collaborators to internal forks. :(

Error

You will get the following error:

- Inviting collaborator "my-oc" with permissions "read" - problem detected: #<Octokit::UnprocessableEntity: PUT https://api.github.com/repos/my-organization/my-internally-forked-repository-name/collaborators/my-oc: 422 - Validation Failed
Error summary:
  resource: Repository
  code: custom
  message: Users outside of the enterprise account cannot be invited // See: https://docs.github.com/rest/reference/repos#add-a-repository-collaborator> ❌

[JeroenKnoops]

Workaround

Also grant access to the upstream. When this invitation is accepted, the downstream / fork will also be accepted.

[pattacini]

Thanks @JeroenKnoops for sharing this use case and a possible workaround 👍🏻

I really look forward to having internal forks in GA soon.