mercure: init at 0.15.5

[gaelreyrol]

Description of changes

This PR adds mercure package: https://github.com/dunglas/mercure

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/)
• 23.11 Release Notes (or backporting 23.05 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
• Fits CONTRIBUTING.md.

[gaelreyrol]

@GrahamcOfBorg build mercure-legacy

[doronbehar]

I am a bit confused. The packages use exactly the same source. All the arguments are the same besides the subPackages and excludedPackages. Why is upstream maintaining both of these variants in the same repo / branch? Perhaps only one variant should be included in Nixpkgs. Even if not, could you at least merge the expressions into one?

I'd suggest the following:

Write a single mercure/default.nix file, with a , legacy ? false argument. Then, write a comment near it saying something like this:

# Enabling the legacy build will build only Go's subPackages <...>, 
# as documented upstream here: <link>

And in all-packages.nix, don't add mercure-legacy, especially if using it is considered discouraged, especially if it is called "legacy". Perhaps in the comment above, you can mention that in order to build it you have to add the package (pkgs.mercure.override { legacy = true;}) to one's NixOS / home-manager configuration.

[gaelreyrol]

@doronbehar Thanks for your feedback, I've decided to remove the legacy package as I don't think it is worth maintaining it.

[doronbehar]

Looks good. Ping me when CI is green.