[ruby-on-rails] rails bundle clean

After updating a bundle, you will have some gems that may be obsolete -- since a newer version of that gem has been installed. There is no such command under the bundle executable i.e. bundle clean. How does one get rid of these obsolete gems?

This is an attempt to reduce slug size in my rails app.

Just remove the obsolete gems from your Gemfile. If you're talking about Heroku (you didn't mention that) then the slug is compiled each new release, just using the current contents of that file.

I assume you install gems into vendor/bundle? If so, why not just delete all the gems and do a clean bundle install?

Just execute, to clean gems obsolete and remove print warningns after bundle.

bundle clean --force

If you're using RVM you may use rvm gemset empty for the current gemset - this command will remove all gems installed to the current gemset (gemset itself will stay in place). Then run bundle install in order to install actual versions of gems. Also be sure that you do not delete such general gems as rake, bundler and so on during rvm gemset empty (if it is the case then install them manually via gem install prior to bundle install).

When searching for an answer to the very same question I came across gem_unused.
You also might wanna read this article: http://chill.manilla.com/2012/12/31/clean-up-your-dirty-gemsets/
The source code is available on GitHub: https://github.com/apolzon/gem_unused

If you are using RVM you can install your gems into gemsets. That way when you want to perform a full cleanup you can simply remove the gemset, which in turn removes all the gems installed in it. Your other option is to simply uninstall your unused gems and re-run your bundle install command.

Since bundler is meant to be a project-per-project gem versioning tool it does not provide a bundle clean command. Doing so would mean the possibility of removing gems associated with other projects as well, which would not be desirable. That means that bundler is probably the wrong tool to use to manage your gem directory. My personal recommendation would be to use RVM gemsets to sandbox your gems in certain projects or ruby versions.

Honestly, I had problems with bundler circular dependencies and the best way to go is rm -rf .bundle. Save yourselves the headache and just use the hammer.