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rubyapirubygemsbundler

Parsing a Gemfile.lock with Bundler

Basically, I'm trying to build a gem that does some form of test failure when certain dependencies are outdated. In the testing framework I can easily stub the crap out of Gem so that Gem.loaded_specs("foo") returns the spec for the gem foo. What I'm looking for is a way to provide a fixture Gemfile and then parse the lock file.

When I use Gem.loaded_specs it somehow magically knows which Gemfile to use, how do I feed it a different gemfile (ie: my fixture)?

I know somebody mentioned "use bundler" and that makes sense but in my code for the gem I do this:

gem_here = Gem.loaded_specs[gem_name]
gem_here.nil? ? :not_in_bundle : gem_here.version.to_s

I need to make this work with my fixture Gemfile and not the current projects gemfile.

Does this make any sense? Sorry if this is vague.

Note: I'm not trying to do this via the CLI. I'd like to use programmatic (ie: ruby api) methods if I can.

Edit:

I'm going with this kind of source now:

gem_here = Bundler.load.specs.detect do |specs|
  specs.name == gem_name
end
gem_here.nil? ? :not_in_bundle : gem_here.version.to_s
Solution

  • Parsing yourself isn’t desirable as Bundler does the heavy-lifting (parsing, dependency resolution).

    Bundler::LockfileParser.new(Bundler.read_file(Bundler.default_lockfile))

    Then, use gemspecs and the lockfile to visit all runtime and/or development dependencies. Runtime/development deps for specific gems are available via a (currently undocumented, needs contrib) RubyGems JSON API https://api.rubygems.org/api/v2/rubygems/rails/versions/5.0.0.1.json

    Note: Bundler 2.0 Gemfile.lock -> gems.locked