Requiring `bundler/setup` gets wrong version
The statement 'require "bundler/setup"' always loads the version that ships with ruby (Bundler 1.17.2 as of Ruby 2.6.1), even if a newer version of Bundler is installed via RubyGems. On the other hand, requiring plain "bundler" gets the gem-installed version.
$ ruby -rbundler -e 'puts Bundler::VERSION'
$ ruby -rbundler/setup -e 'puts Bundler::VERSION'
This breaks pretty much all my bundled applications, which start by requiring
bundler/setup, which fails when the Gemfile.lock was created by Bundler 2.x and the loaded Bundler is 1.x.