This PR replaces the haskell4nix-based Nix setup with a Nix flakes + haskell.nix-based setup and adds a github action for building and caching it. It also replaces the existing default.nix and shell.nix files and turns them into a wrapper for the flake.nix so that nix-build and nix-shell keeps working as before. This allows us to deduplicate the Nix definitions and also allows these legacy commands to take advantage of the binary cache populated by the flake.
One useful feature of the old haskell4nix-based setup that we're losing with this transition is the ability to "inline" our dependencies in the dep folder using nix-thunk and work on them through that local checkout. Fortunately, it's still possible to work with local copies of the dependencies with a little more work:
For example, assume that there's a local chainweb-api copy at ../chainweb-api relative to the kda-tool repo.
Copy the cabal.project file: cp cabal.project cabal.project.local
In cabal.project.local, remove the source-repository-package section for chainweb-api and instead add ../chainweb-api/chainweb-api.cabal at the end of the packages: kda-tool.cabal line.
Start nix develop as usual, which will still use cabal.project.
In the shell, call cabal with --project-file=cabal.project.local in order to work with the local chainweb-api copy.
This PR replaces the
haskell4nix-based Nix setup with a Nix flakes +haskell.nix-based setup and adds a github action for building and caching it. It also replaces the existingdefault.nixandshell.nixfiles and turns them into a wrapper for theflake.nixso thatnix-buildandnix-shellkeeps working as before. This allows us to deduplicate the Nix definitions and also allows these legacy commands to take advantage of the binary cache populated by the flake.One useful feature of the old
haskell4nix-based setup that we're losing with this transition is the ability to "inline" our dependencies in thedepfolder usingnix-thunkand work on them through that local checkout. Fortunately, it's still possible to work with local copies of the dependencies with a little more work:chainweb-apicopy at../chainweb-apirelative to thekda-toolrepo.cabal.projectfile:cp cabal.project cabal.project.localcabal.project.local, remove thesource-repository-packagesection forchainweb-apiand instead add../chainweb-api/chainweb-api.cabalat the end of thepackages: kda-tool.caballine.nix developas usual, which will still usecabal.project.cabalwith--project-file=cabal.project.localin order to work with the localchainweb-apicopy.