Possible Recursion in Deps Pipelines

Looking at a dependency pipeline build of Grafana, or this pipeline with libpng, it seems that we're recursing.

The error at the bottom of the libpng build reads:

dependencies_io_check - failed - (reached maximum depth of child pipelines)

Digging into the continuous integration files, here is what I think is happening.

First, we run .gitlab-ci.yml.

The dependencies_io_check job will run if the branch name starts with deps.

dependencies_io_check:
  extends: .trigger-job
  when: always
  variables:
    ee: "true"
  rules:
    # Because of inherit:variables being false, `PIPELINE_TYPE` isn't available here. :(
    # https://gitlab.com/gitlab-org/gitlab/-/issues/368759
    - if: '$CI_MERGE_REQUEST_SOURCE_BRANCH_NAME =~ /^deps/ || $CI_COMMIT_BRANCH =~ /^deps/'

The trigger-job which it extends, is a trigger. This means that the job will trigger a pipeline, which then in turn runs dependencies_io_check, which then triggers a pipeline, and so on as long as the branch name starts with deps.

The workflow rule in trigger-job may have been what we intended to stop it, but the rules are not first one fails like a firewall, they keep checking to see if any work. Thus, the dependencies_io_check job always runs and just keeps triggering itself.