Bundler::Source::Git: avoid re-fetching the repo

[byroot]

In install, self.to_s is called by print_using_message "Using ... from #{self}. This in turn calls current_branch which if the local git cache is missing will re-clone it from scratch.

This is an issue, because a common optimisation for build system that are bundler aware is to prune bundler's cache to remove large git repositories.

See my feature request from 2020 for context: #7018

In our case, these git repositories account for over 50% of the bundler cache, causing the cache restoration and persist steps to be very significantly slowed down.

Overall I don't think triggering a full on git clone operation from a call to to_s make sense.

NB: This can be worked around by always specifying a ref: argument on the gem.

[hsbt]

|| @branch looks unreachable: @ref includes options["branch"], so whenever @branch is set humanized_ref already returns it. at = humanized_ref alone should be equivalent.

[hsbt]

👍 Can you look my comment? I will merge this after that.

[byroot]

@hsbt done!

Also while I have you, what do you think of that old feature request? #7018

I think it could turn into either a bundle prune command, or bundle install --prune or bundle clean --prune.

It's a thing lots of people are doing including the Ruby heroku buildpack:

• https://github.com/heroku/heroku-buildpack-ruby/blob/4b1b6ed6740e2c25b7f5064c67b2653713bc6341/lib/language_pack/ruby.rb#L718-L720
• https://github.com/heroku/heroku-buildpack-ruby/blob/4b1b6ed6740e2c25b7f5064c67b2653713bc6341/lib/language_pack/ruby.rb#L684

[hsbt]

@byroot I'm positive about providing an official prune feature.

I'm not sure what the right interface would be. An environment variable, a flag on an existing command, and a separate bundle prune subcommand all seem plausible to me. Do you have a preference method?

[byroot]

Do you have a preference method?

I suppose we could have them all, but if we go to the absolutely essential one, then I think it would be an environment variable, e.g. BUNDLE_PRUNE and BUNDLE_DEPLOYMENT would implies BUNDLE_PRUNE by default.

[byroot]

It's a thing lots of people are doing including the Ruby heroku buildpack:

And also the Rails default Dockerfile: https://github.com/rails/rails/blob/8d07fafa447e4979da96389a3f58cace92964ef2/railties/lib/rails/generators/rails/app/templates/Dockerfile.tt#L68

[byroot]

NB: the lint step failed because of some GItHub issue, but I don't have the permissions to re-run it. I think other than that the PR is green.

[hsbt]

oh, thanks. I re-run that job.