Changing username breaks bundler plugins

[JackMc]

The issue

I changed my username on my Mac from jackmccracken to jackmc. This seems to have confused bundler's plugin index which stores the absolute path for each plugin:

[jackmc@jackbook ~/some/project] % cat ~/.bundle/plugin/index 
---
commands:
hooks:
  after-install:
  - "extended_bundler-errors"
  before-install-all:
  - "extended_bundler-errors"
load_paths:
  extended_bundler-errors:
  - "/Users/jackmccracken/.bundle/plugin/gems/extended_bundler-errors-0.3.1/lib"
plugin_paths:
  extended_bundler-errors: "/Users/jackmccracken/.bundle/plugin/gems/extended_bundler-errors-0.3.1"
sources:

Note /Users/jackmccracken (my old username). This index should probably be invalidated if bundler realizes that its .bundle directory location has changed.

Steps to reproduce (and workaround)

1. Install some bundler plugin (for example https://github.com/jules2689/extended_bundler-errors)
2. Run bundle install in some project and observe that it works
3. Change your username on macOS (not sure if this happens on other platforms): https://support.apple.com/en-ca/HT201548
4. Run bundle install in any project, observe the following error (substituting your old username for jackmccracken: /opt/rubies/2.5.3/lib/ruby/site_ruby/2.5.0/bundler/plugin.rb:271:in 'load': cannot load such file -- /Users/jackmccracken/.bundle/plugin/gems/extended_bundler-errors-0.3.1/plugins.rb (LoadError)
5. Edit ~/.bundle/plugin/index, swapping out the old username for the new one
6. bundle install again, observe that it works again

[jules2689]

This is caused by https://github.com/bundler/bundler/blob/d44d803357506895555ff97f73e60d593820a0de/lib/bundler/rubygems_ext.rb#L47-L57 which gives a fully qualified path. Is there a reason for this @segiddins ?

[segiddins]

Full gem path always returns an absolute path in RubyGems , I believe

[jules2689]

That makes sense, but do we serialize the full path in any other persistent file?

[colby-swandale]

It would be good if we didn't have the full path of the gem being written into the plugin index.

[jules2689]

That was my thought too... But I'm unsure of the implications throughout the code base. Might be best to contract and expand the URL in the plugin save/load code... But I wonder if this is an issue anywhere else.

[aogata-inst]

FWIW our team experienced this issue in a different way:

# pwd
/Users/myusername/my-repo

# on host machine, creates /Users/myusername/my-repo/.bundle/plugin/index
bundle install

# tries to use the absolute path, but fails because it doesn't exist in the container
docker-compose run --rm web bundle install 

This repo runs rubocop on the host machine as a pre-commit hook, but development is typically done through docker. Since our plugin is defined using the path: syntax, it seems like storing the relative path in the index file could help make this use case behave a bit more sanely.