vagrant

https://github.com/mitchellh/vagrant

Ruby

Vagrant is a tool for building and distributing development environments.

Vagrant::Config::VersionBase.upgrade

This is called if a previous version of configuration needs to be
upgraded to this version. Each version of configuration should know
how to upgrade the version immediately prior to it. This should be
a best effort upgrade that makes many assumptions. The goal is for
this to work in almost every case, but perhaps with some warnings.
The return value for this is a 3-tuple: `[object, warnings, errors]`,
where `object` is the upgraded configuration object, `warnings` is
an array of warning messages, and `errors` is an array of error
messages.

Source | Google | Stack overflow

Edit

git clone [email protected]:mitchellh/vagrant.git

cd vagrant

open lib/vagrant/config/version_base.rb

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Vagrant--Config--VersionBase-upgrade-for-pr

# Commit to git

git add lib/vagrant/config/version_base.rbgit commit -m "better docs for Vagrant::Config::VersionBase.upgrade"

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-Vagrant--Config--VersionBase-upgrade-for-pr

hub pull-request

# Celebrate!