Support loading of GitLab `!reference` data during validation about check-jsonschema HOT 1 OPEN

Thanks for the detailed report!

Looking back at #112 and looking at the implementation, it looks like the current implementation of !reference is just a passthrough which requires the YAML node to be a list.

I think this request will require implementing actual !reference loading, which will also require an implementation of the include directive.

include requires, in turn, a body of features around cloning a referenced GitLab repo, which makes the scope of this feature nontrivial.
One notable caveat is that this cannot work in an environment like pre-commit.ci in which the network is intentionally locked down. There are a good number of other considerations about how to handle this, so I'm not sure how prepared I am to work on this as a feature right now.

I'm wondering if there is perhaps a simpler solution which would get you unblocked in the near term.
Perhaps if some capability were added to substitute data in for a reference from a local file? This has come up in other contexts, so if it would be useful to you to be able to stub something in for the !reference node, I can cross-reference what notes and info I have and consider planning something in the near term.

As a brief aside, you can omit the args from your hook declaration:

       - id: check-gitlab-ci
-        args: ["--data-transform", "gitlab-ci"]

The check-gitlab-ci hook automatically includes the transform. But there's no harm in specifying it twice.

from check-jsonschema.