Mission

Every time we branch off a release we stabilize the release branch.
Our goal here is to get as little as possible jobs failing on the trunk/master jobsets.
We call this effort "Zero Hydra Failure".
I'd like to heighten, while it's great to focus on zero as our goal, it's essentially to
have all deliverables that worked in the previous release work here also.

Please note the changes included in RFC 85.

Most significantly, branch off will occur on 2022 May 22; prior to that date, ZHF will be conducted
on master; after that date, ZHF will be conducted on the release channel using a backport
workflow similar to previous ZHFs.

Jobsets

trunk Jobset (includes linux, darwin, and aarch64-linux builds)
nixos/combined Jobset (includes many nixos tests)

How to help (textual)

1. Select an evaluation of the trunk jobset
   

2. Find a failed job ❌️ , you can use the filter field to scope packages to your platform, or search for packages that are relevant to you.
   
   Note: you can filter for architecture by filtering for it, eg: https://hydra.nixos.org/eval/1719540?filter=x86_64-linux&compare=1719463&full=#tabs-still-fail

3. Search to see if a PR is not already open for the package. It there is one, please help review it.

4. If there is no open PR, troubleshoot why it's failing and fix it.

5. Create a Pull Request with the fix targeting master, wait for it to be merged.
   If your PR causes around 500+ rebuilds, it's preferred to target staging to avoid compute and storage churn. If your PR is fixing Haskell packages, target the haskell-updates branch instead.

6. (after 2022 May 22) Please follow backporting steps and target the release-22.05 branch if the original PR landed in master or staging-22.05 if the PR landed in staging. Be sure to do git cherry-pick -x <rev> on the commits that landed in unstable. @jonringer created a video covering the backport process.

Always reference this issue in the body of your PR:

ZHF: #172160

Please ping @NixOS/nixos-release-managers on the PR and add the 0.kind: build failure label to the pull request.
If you're unable to because you're not a member of the NixOS org please ping @dasJ, @tomberek, @jonringer, @Mic92

How can I easily check packages that I maintain?

I have created an experimental website that automatically crawls Hydra and lists packages by maintainer and lists the most important dependencies (failing packages with the most dependants).
You can reach it here: https://zh.fail

If you prefer the command-line way, you can also check failing packages that you maintain by running:

# from root of nixpkgs
nix-build maintainers/scripts/build.nix --argstr maintainer <name>

New to nixpkgs?

• Packaging a basic C application
• Python nix packaging
• Adding a package to nixpkgs
• other resources at: https://github.com/nix-community/awesome-nix
• https://nix.dev/tutorials/

Packages that don't get fixed

The remaining packages will be marked as broken before the release (on the failing platforms).
You can do this like:

meta = {
  # ref to issue/explanation
  # `true` is for everything
  broken = stdenv.isDarwin; 
};

Closing

This is a great way to help NixOS, and it is a great time for new contributors to start their nixpkgs adventure. 🥳

As with the feature freeze issue, please keep discussion here to a minimal so you don't ping all maintainers (although relevant comments can of course be added here if they are directly ZHF-related) and ping me or the release managers team in the respective issues.

cc @NixOS/nixpkgs-committers @NixOS/nixpkgs-maintainers @NixOS/release-engineers

Related Issues

• Timeline: Release Schedule for 22.05 #165792
• Feature Freeze Items: 22.05 Feature Freeze #167025