update resolver, package with nix

[chris-martin]

If you want to try out the Nix package, you can run:

nix shell \
  'github:freckle/stack-lint-extra-deps?ref=chris/pkg' \
  --command stack-lint-extra-deps --help

It should just download the pre-built binary the Freckle public cache (if the github actions for your platform have finished running).

This is my first time trying out stacklock2nix; it seems pretty okay.

Tagging Pat plus anyone Nix-using or Nix-curious.

[chris-martin]

Not sure why the macos check is failing. It doesn't seem related to the change.

• First run - I see one similar report but no conclusive answer. The failure seems to be ephemeral.
• Third run - Wonder if it has something to do with github's runners switching architecture on macos-latest. Yep... Holding the runner back to macos-12 seems to fix it.

[chris-martin]

Bizarre, Linux and MacOS are getting different hashes for the all-cabal-hashes input.

[cdepillabout]

Bizarre, Linux and MacOS are getting different hashes for the all-cabal-hashes input.

I vaguely remember seeing this before, due to how all-cabal-hashes has multiple files with names that differ only by case. If you try to unpack this file on a filesystem that doesn't allow the same file name with multiple casings, Nix gives you a different hash.

I forget off the top of my head what the workaround for this is, but you could try pulling all-cabal-hashes down as a tarball. I believe that might get rid of this error:

https://github.com/cdepillabout/stacklock2nix/blob/22676dfc45fa1c33899ba1da1a23665172a18ba7/CHANGELOG.md?plain=1#L188-L218

The example in this link is showing how to add all-cabal-hashes as a directory, which will likely(?) give the hash error you were seeing.

Instead, you might be able to add all-cabal-hashes as a tarball. This should give the same hash on both Linux and OSX:

https://github.com/cdepillabout/stacklock2nix/blob/22676dfc45fa1c33899ba1da1a23665172a18ba7/test/test-new-package-set.nix#L33-L41

It looks like you might be using flake inputs though, so you'll have to adapt this a little.

[pbrisbin]

Sounds cool, but I know absolutely nothing in this space, so I'll defer review to others.

[StevenXL]

@chris-martin I don't have the required knowledge to give you a review. I'll defer to others, but that leaves @cdepillabout.

P.S. Hi Dennis!!!

[jason-lieb]

Also deferring

[chris-martin]

Checks pass! @cdepillabout thanks a million for the tool and the advice, wouldn't have gotten there without you.

[chris-martin]

Looks like nobody wants to review; I'm going to go ahead since we've also talked about this in Slack, and there's nothing here that can't be undone.