Nix build broken on x86_64-linux

[solomon-b]

I'm trying to build from the master branch:

➜ nix build
error: flake 'git+file:///home/solomon/Development/Haskell/ghc-specter' does not provide attribute 'packages.x86_64-linux.default' or 'defaultPackage.x86_64-linux'

[wavewave]

The recommended use is nix develop .# if you want to build ghc-specter inside the shell or nix develop .#env if you want to have a shell with ghc-specter-daemon executable. In any case, you need to use ghc-specter-plugin as a plugin library (with ghc options: -fplugin Plugin.GHCSpecter -plugin-package ghc-specter-plugin for your target project)

Just to check the nix build usingnix build, please use nix build .#ghc962.ghc-specter-daemon and nix build .#ghc962.ghc-specter-plugin

[solomon-b]

The recommended use is nix develop .# if you want to build ghc-specter inside the shell or nix develop .#env if you want to have a shell with ghc-specter-daemon executable. In any case, you need to use ghc-specter-plugin as a plugin library (with ghc options: -fplugin Plugin.GHCSpecter -plugin-package ghc-specter-plugin for your target project)

Just to check the nix build usingnix build, please use nix build .#ghc962.ghc-specter-daemon and nix build .#ghc962.ghc-specter-plugin

Thanks, I was just trying out the nix build. The README doesn't say this, but I believe I need to add the plugin as a dependency of my project?

Simply calling cabal build --ghc-options "-fplugin Plugin.GHCSpecter -plugin-package ghc-specter-plugin" with the daemon running results in:

<command line>: cannot satisfy -plugin-package ghc-specter-plugin

[wavewave]

Yeah, it's a little tricky to explain it to cover all the cases (in combination of wrapped GHC/ghc-pkg, cabal and nix). Inside the nix shell provided by nix develop .#env, ghc-specter-plugin is already visible by default (as you can check ghc-pkg list), so cabal would know how to satisfy -plugin-package ghc-specter-plugin. But if it's somehow not visible, specifying ghc-specter-plugin as a dependency of a project is a workaround.

In principle, the GHC's plugin system is designed to be outside the dependency list of a project. It's "GHC's dependency", not target project's dependency. So if ghc-specter-plugin is installed somewhere and you know where its package db file is, then you can in fact specify the plugin package explicitly by giving the ghc options -package-db.
I will add the documentation on those configuration troubleshooting. Thanks!