Oci-build-task does not support private base images?

On the main documentation site about resource types we are now told “You will almost always be using the registry-image resource type” - https://concourse-ci.org/resource-types.html

The registry-image resource supports pushing/pulling docker images but does not support building images like the the docker-image resource does. Instead we are pointed to the the oci-build-task (https://github.com/vito/oci-build-task) to pair with the new registry-image resource.

Unfortunately, it does not appear that oci-build-task can build a docker file that uses a private base image, e.g FROM gcr.io/my/private/base-image.

My use case is to build private base image -> augment private base image for test -> retag and push private base image on test pass and this seems most doable using the oci-build-task vs using docker-image to do the re-tagging however I appear to have run into a dead end unless there is a way to get oci-build-task to support private base images that I’m missing.

Thoughts? Suggested alternative approaches? Thanks!

Have you tried importing the base image as a resource for OCI task to deal with?
We need to see the exact error to diagnose.
If possible can you post a (redacted) version of your pipeline so I can get a better idea what you are doing?