Indeed I see that gnu/packages/ruby.scm only packages Bundler v1.17.3,
though Bundler 2 was released in January 2019 [0]. I'm not hugely
familiar with the Ruby ecosystem, but reading the release announcement
suggests that they expect users/developers to have both Bundler 1 and
Bundler 2 available. If I hadn't seen this, I'd have gone ahead and
submitted a patch simply upgrading the Bundler package definition, but
I'm not sure if that will then immediately break every package depending
on it that expects Bundler 1.
Is this a valid concern? Should Guix provide packages for both Bundler
1 and Bundler 2, or would just Bundler 2 be sufficient? I'll still
write a definition for the new version, but I'll hold off submitting a
patch until I've had some feedback.
[0]: https://bundler.io/blog/2019/01/03/announcing-bundler-2.html