support bundler 2.5/2.6 checksum feature

[h0nIg]

A first version of checksums (to enable manually) was published as part of bundler 2.5, the final version was introduced with bundler 2.6.

ruby/rubygems#3379
ruby/rubygems#7217 (manual enablement through bundler 2.5)

Bundler supports writing checksums into the Gemfile.lock, therefore making the gemset.nix obsolete. The checksums are in the following format:

GEM
  remote: https://rubygems.org/

CHECKSUMS
  ast (2.4.2) sha256=1e280232e6a33754cde542bc5ef85520b74db2aac73ec14acef453784447cc12
  aws-eventstream (1.3.0) sha256=f1434cc03ab2248756eb02cfa45e900e59a061d7fbdc4a9fd82a5dd23d796d3f

If we take ast as an example, the hash is the same which is stored in gemset.nix

{
  ast = {
    groups = ["default" "test"];
    platforms = [];
    source = {
      remotes = ["https://rubygems.org/"];
      sha256 = "04nc8x27hlzlrr5c2gn7mar4vdr0apw5xg22wp6m8dx3wqr04a0y";
      type = "gem";
    };
    version = "2.4.2";
  };

# nix hash to-base32 --type sha256 1e280232e6a33754cde542bc5ef85520b74db2aac73ec14acef453784447cc12
04nc8x27hlzlrr5c2gn7mar4vdr0apw5xg22wp6m8dx3wqr04a0y

Can you please enable this feature in bundix, so Gemset.lock will take precedence?

[amarshall]

As mentioned in the nixpkgs issue, I have code to do this. It won’t be part of Bundix, though, as it’s so fundamentally different and most of the Bundix code doesn’t apply at all.

[h0nIg]

@marsam @manveru may I ask for a review, as this is a reasonable feature which should be supported? The Implementation #119 is minimalistic and is supported with bundler 2.5 already (hidden through an existence check for "CHECKSUMS" section)

[cramt]

i got something working for my usecase, https://github.com/cramt/nixconf/blob/main/gems/default.nix, atleast until something like this gets upstreamed into nixpkgs