Be able to reference stack's package set

[domenkozar]

I'd like to be able to build all packages in packages: part of stack.yaml and all their components.

This would be a simple way to emulate stack test.

[angerman]

So what you ultimately want is to collect the test-derivations for all the "active" packages?

[angerman]

This turns out to be a bit more tricky, stack-to-nix will aggregate packages: and extra-deps:

https://github.com/input-output-hk/nix-tools/blob/b1efc35f344995f546b14da7914d7c0c0cdf5fa8/stack2nix/Stack2nix/Stack.hs#L181-L188

Hence I beleive the solution here would have to be to annotate the parsed info, and add it to the produced nix expression. Same should probably hold for project-to-nix.

If someone is willing to take a look at this, I'm happy to review and advise!

[kutyel]

I’m not sure about emulating stack test, in our use case we want to build all packages, so I thinks it’s more related to emulate stack build?

[angerman]

@kutyel what does “all packages” mean? stack-to-nix will merge extra-deps and packages when parsing the stack file. We could probably get that set (packages + extra-deps) separately.
However without knowing what “all packages” really refers to, I have no way of telling if that would match the expectation.

Ideally you’d provide a small sample to illustrate the intended outcome?

[kutyel]

By "all packages" we mean all components defined in the packages: sections of the stack.yaml 😉

For reference, have a look at this file, ideally we'd like to deduce those from the root stack.yaml. Does it make sense?

[rvl]

In PR #242 @hamishmack added isLocal to cabal-to-nix and isLocalPackage and selectLocalPackages to Haskell.nix - which I think should solve your problem. It still needs documentation and a test case though.

[domenkozar]

@rvl that sounds great! I'm always confused a bit out the api, where do I pass in selectLocalPackages?

[rvl]

You would add something like this to your ci.nix:

haskellPackages = import ./nix/pkgs.nix { ... blah blah ... };
tests = pkgs.haskell-nix.haskellLib.collectComponents "tests" pkgs.haskell-nix.haskellLib.isLocalPackage haskellPackages;

The selectLocalPackages function would be used with shellFor. (shellFor and collectComponents are documented)

I had not tried it before and I can see now that it doesn't quite work - if there are extra-deps in stack.yaml which are git repos, then they are counted as "local", which is not correct.

[kutyel]

Any update on this? 😄

[domenkozar]

I plan to play with this and write a blog post, but next month :)

[stale]

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