I think we have consensus on what “custom base images in repo2docker” should look like: https://github.com/jupyter/repo2docker/issues/487#issuecomment-479794426 and the next few comments after the linked one (plus really the whole thread for several options that were considered, trade-offs, prototypes and alternatives. I like the converged upon idea and would recommend we try to implement it before re-opening the discussion. Otherwise we spend forever talking and not so much doing. We aren’t yet a committee
I’d be -1 on adding nbgitpuller to repo2docker because it is niche. A constant battle is the perception that repo2docker created images contain “bloat” or “for real uses cases one needs a custom
Dockerfile to remove bloat” etc etc. So we should make an effort to keep thing slim (because they are!) which means only adding things to core repo2docker that are used very widely, even if (like nbgitpuller) they don’t actually increase the image size all that much. Instead more documentation and “cookie cutter” repos specialised to these use cases.
Those are my thoughts on how to address this.
On a more positive note: having new, other, more user interfaces and user experiences for how to create your “binder link” is very cool. They can and should be hosted/built separately of BinderHub. The fact that it doesn’t need the central oversight committee to agree to any of it is a feature