github PRs: utilize nixpkgs-lint

[vcunat]

It would be nice if it auto-reminded of missing or bad meta-data. (Follow up from #9966.)

[pSub]

This is also covered in #11166. I will try to tackle this in the next days.

[domenkozar]

🍰 I know that @mbbx6spp might be working on a linter :)

[pSub]

For the integration into Github I see the following possibilities:

• https://github.com/markstory/lint-review
• https://linthub.io/
• https://github.com/thoughtbot/hound
• Come up with a own solution

For all existing solution we would have to implement the integration with nixpkgs-lint.

@mbbx6spp what are you working on concretely?

[pSub]

Update: I am currently working on nixpkgs-lint integration into markstory/lint-review. I hope I have some results tomorrow.

[grahamc]

I have lint running on every PR on my personal build server. I've been working to leave feedback on PRs when I notice it reporting a degradation, but it is a bit tricky to detect which package(s) were changed and if the change was for a good / worse. Right now I have it with a diff (a bit hacky...):

#!/bin/sh

set -eux

git fetch origin

# $upstream is `master` or `release-15.09`, the branch being merged in to
git checkout "origin/$upstream"


nixpkgs-lint -f . > lint-from-target-branch

git merge "$current_branch"
nixpkgs-lint -f . > lint-from-pr

diff lint-from-target-branch lint-from-pr

If there is a good way to determine which packages need to be run against, I'd be happy to improve it and more readily leave feedback.

[pSub]

I do not have a solution for finding the packages that have changed. However, I do no think that it is necessary to have this information. My current plan is to modify nixpkgs-lint s.t. it prints information about the position of the problem (path to the file and line number) and then append this information to the PR via a tool like lint-review.

This looks like

pkgs/misc/beep/default.nix:20: Lacks a maintainer
pkgs/misc/beep/default.nix:20: Description contains package name

The modification of nixpkgs-lint is nearly done and I will push it in the next ~2 days. I also hope to have enough time to set up lint-review to work with nixpkgs-lint next week.

[matthewbauer]

@pSub Is this still a work in progress? We can get Travis to run "nixpkgs-lint" but it won't be well formatted.

If we can get "lint-review" in nixpkgs, could we have it run on one of the Hydra machines?

[cmfwyp]

Followup to my suggestion on #17458 to only check modified packages. The nixpkgs-lint script needs a package name, so we just need a way to determine which packages have been modified by a commit. This could be done by getting the paths of Nix expressions for modified packages from git diff --numstat HEAD~1 | grep -o 'pkgs/.*\.nix', extracting the package name from the files by capturing it with name = "(.+)";, then passing the name to nixpkgs-lint with the --package option.

Only two issues: commits in branches other than master, which would require finding that branch and doing a git checkout first, and files that contain lines matching name = "(.+)"; where the capture isn't actually a package name, if these exist.

Adding this to travis-nox-review-pr.sh might work:

for line in "$(git diff --numstat HEAD~1 | grep -o 'pkgs/.*\.nix')"
do
    nix-shell --packages nixpkgs-lint --run "nixpkgs-lint -f $TRAVIS_BUILD_DIR -p $(grep -o 'name = ".*";' $line | tail -c +9 | head -c -2)"
done

[Profpatsch]

Also see #37252 which was created to be able to type-check arbitrary (non-contravariant, aka no functions) nix data.

There is a working proof of concept for checking the whole of meta and the contents of derivations, you can find it here and see the types and the result of one such evaluation here.

[Profpatsch]

@pSub Are you closing because it is fixed or because you stopped working on it? Since we have ofborg now, it seems to be more relevant now then when the issue was opened.