Pipeline should include builds in all forks, not the parent project; not working

Hi everyone,

I have a use case where I need some build jobs to run on forks of a project, but not on a push to the parent project itself.

A snippet of the .gitlab-ci.yml:

  stage: build
    - branches
    - branches@my/upstream
  - ...STUFF...

However, this does not work, as I see these builds included on pipelines of the parent project. Can anyone see what I am doing wrong? I’d love for there to be a tool you could run a .gitlab-ci.yml through with conditions, and get a dry-run of what the pipelines would look like. It’d be very useful for complex pipelines.