Is it possible to create a "fallback branch" (a.k.a

prod

) such that my development branch use that materialized versions of my upstream dependencies when not materialized yet on my branch?

we did some experimenting with a BranchingIOManager that can do this. It’s still a very experimental feature, and one we haven’t invested much time into recently, so you’ll need to do a bigtof spelunking through the code base, and it may end up being easier for you to write your own io manager based on what we have here main base class: https://github.com/dagster-io/dagster/blob/master/python_modules/dagster/dagster/_core/storage/branching/branching_io_manager.py#L34 various usages - https://github.com/search?q=repo%3Adagster-io%2Fdagster%20BranchingIOManager&type=code