nixpkgs-vet should throw error when package attribute name in by-name is prefixed with a number

[Aleksanaa]

In NixOS/nixpkgs#333281 the package attribute name is prefixed with 1 but nixpkgs-vet agreed with that. This may cause problems for us later, as nix treats "1a", 1a and _1a differently. I edited the title to rerun the check and confirmed that it still didn't throw an error.

[philiptaron]

I see that this does actually work through both nix build .#1fps and nix-build -A 1fps, though, and also works if the attrset name is stringified.

nix-repl> pkgs."1fps"
«derivation /nix/store/b8d1br1rjq4i1yw8w5l71b5c26cqacrz-1fps-0.1.10.drv»

nix-repl> pkgs.1fps
error: undefined variable 'fps'

       at «string»:1:7:

            1| pkgs.1fps
             |       ^

Is the core reason it should be discouraged that a package like this can't be expressed as a dependency in callPackage argument lists?

nix-repl> { 1fps }: null
error: syntax error, unexpected INT

       at «string»:1:3:

            1| { 1
             |   ^

[Aleksanaa]

Is the core reason it should be discouraged that a package like this can't be expressed as a dependency in callPackage argument lists?

...Yes, in other situations we just need quotes.

[infinisil]

Oh this would be nice, and should be simple to implement

[infinisil]

I'll refrain from implementing this, I think this is a great first issue for perhaps a new contributor

[Aleksanaa]

https://github.com/NixOS/nixpkgs-vet/blob/main/src/structure.rs#L16-L19

The correct regex would be:

shard: ^((_[0-9])|([a-z][a-z0-9_-]?))$
package: ^((_[0-9])|[a-zA-Z])[a-zA-Z0-9_-]*$