check-meta.nix: make non-source consistent with documentation

[ghost]

Description of changes

The documentation for meta.sourceProvenance in doc/stdenv/meta.chapter.md says: "the meta.sourceProvenance attribute should be a list containing one or more value..."

Let's update check-meta.nix to require that meta.sourceProvenance is a list, as the documentation says, rather than a single element.

Adding two extra keystrokes [ and ] when filling out this field is an insignificant burden for package authors, and being able to assume that the meta.sourceProvenance field is always a list greatly simplifies any code that acts on the value of this field. For example, it simplifies the sourceProvenance example given in check-meta.nix; the simplification is included in this PR.

Since meta.sourceProvenance was just merged a few hours ago now is the easiest time to fix this: nobody is using the feature yet.

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/)
• 22.05 Release Notes (or backporting 21.11 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.

[ghost]

@risicle should be added as a reviewer (am I able to add reviewers to my own PRs?)

[Artturin]

@risicle should be added as a reviewer (am I able to add reviewers to my own PRs?)

Yes it you're a member of the maintainer team which you can join by being a maintainer of a package and accepting the invite

[ghost]

Yes it you're a member of the maintainer team which you can join by being a maintainer of a package and accepting the invite

Yeah, I really procrastinated a long time before doing this.

[ghost]

Resolved the merge conflict and squashed.

[risicle]

What error does this now give if you assign a single sourceType then?

[ghost]

Using these instructions:

$ curl -o outpaths.nix https://raw.githubusercontent.com/NixOS/ofborg/released/ofborg/src/outpaths.nix
$ GC_INITIAL_HEAP_SIZE=4g nix-env -f ./outpaths.nix -qaP --no-name --out-path --arg checkMeta true > out-paths
error: value is a set while a list was expected

       at /git/nixpkgs/pkgs/stdenv/generic/check-meta.nix:93:30:

           92|
           93|   isNonSource = sourceTypes: lib.lists.any (t: !t.isSource) sourceTypes;
             |                              ^
           94|
(use '--show-trace' to show detailed location information)

[ghost]

If you want to see what OfBorg's complaint would look like, see this, from #180036.

[ghost]

Rebased.