haskellPackages: ignore maintainers without email

[cdepillabout]

Description of changes

The Hydra report generator was failing in https://github.com/cdepillabout/nix-haskell-updates-status/actions/runs/4036712903/jobs/6939513150 because there was a user recently(?) added that does not have an email address:

The Haskell Hydra report generator (maintainers/scripts/haskell/hydra-report.hs) uses the maintainer-handles.nix script for generating a mapping of email addresses to GitHub handles.

This maintainer-handles.nix script is necessary because the Haskell Hydra report generator gets Hydra job status info as input, but needs to ping users on GitHub. Hydra job status info only contains user emails (not GitHub handles). So the maintainer-handles.nix script is necessary for looking up GitHub handles from email addresses.

This PR fixes the maintainers-handles.nix code to ignore maintainers that don't have email addresses. The code was originally assuming that all maintainers have email addresses, but there was recently a maintainer added without an email address.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[cdepillabout]

Allowing maintainers to not have an email address was added in #209165.

[ncfavier]

Hydra job status info only contains user emails (not GitHub handles).

Would be nice to fix that in Hydra.

Or just cut out the middle man and construct the mapping "job name → GitHub handle" from nixpkgs directly?

[cdepillabout]

Or just cut out the middle man and construct the mapping "job name → GitHub handle" from nixpkgs directly?

Yeah, that sounds like it might be the ideal thing to do, although I'm not sure how much work it would be.

I think just ignoring maintainers without an email address is the easiest immediate thing we can do, but this definitely sounds like a good future improvement.