Specifying a custom remote-repo in a cabal sandbox

Question

I would like to work on a project in a cabal sandbox. But instead of using the same remote-repo as my non-sandboxed code (i.e., Hackage), I'd like to point to a different remote repo. I tried creating a cabal.config file in the project directory with a remote-repo line, but it seemed to have no effect; running cabal update after that indicated that Hackage was being downloaded, but not my custom repo.

Is this use case supported, and if so, how do I achieve it?

Answer 1

This is in fact a Cabal bug, I've opened a Github issue about it.