active-repositories in cabal.project does not override cabal.config

[brandonchinn178]

Describe the bug
Running ghc-wasm-meta's setup.sh script adds active-repositories: hackage.haskell.org, head.hackage.haskell.org:override to ~/.cabal/cabal.config and runs cabal update.

In my project, I have cabal.project with active-repositories: hackage.haskell.org, but cabal update is still showing head.hackage. I would expect active-repositories in cabal.project to override cabal.config; is that assumption wrong? How do I prevent using head.hackage without patching the script to not set head.hackage?

System information

• Operating system
• cabal, ghc versions

Additional context
Add any other context about the problem here.

[ulysses4ever]

This is closely related to

• Document how multiple package repositories are combined #8730

tldr; is that overriding is not currently implemented, and it's not clear that it should override one another: you could argue either way. There is a more general design question: how to make all users happy, those who want override-semantics and those who want add-semantics, so that we avoid doing an arbitrary irreversible choice between the semantics. The way forward would be to have someone proposing a design supporting both semantics, and if people are happy with it, implementing it.

[andreabedini]

Other related tickets are #8997, #8863, and #8502