Issues with Bundler 1.16.0 and Rubygems 2.7

Short story

Recently we’ve been having trouble with new versions of bundler and rubygems on Travis. I’m still investigating the Automate failures.

Long story

We had problems a few days ago with rubygems 2.7.0 and bundler 1.16.0 and the error was that it couldn’t require 'concurrent/map'.
So the hack we put in place to “fix” it was to gem uninstall bundler 1.16.0 and gem install bundler 1.15.4.
Then Travis updated the ruby 2.3.1 container to rubygems 2.7.1 and that failed to gem uninstall bundler 1.16.0 because it’s part of rubygems and you can’t uninstall the default version.
So yesterday I removed the hack and it started working fine again.
Today Travis updated the ruby 2.3.1 image to use rubygems 2.7.2 and now automate fails again
so I have to dig into it more to find out what the real error is because all we get from automate is “Unknown RC from method”.

Related issues:

Fixed by for the resolution. If you set the bundler path for update or install, gems may be installed somewhere outside of the gem path. When using Bundler.with_clean_env, it resets the environment for new processes to what existed before Bundler was loaded. Therefore, any gems installed by Bundler to a path not on the gem path will not be accessible. This PR ensures that the Bundler path is on the gem path so that all gems are accessible.