chef

https://github.com/opscode/chef

Ruby

A systems integration framework, built to bring the benefits of configuration management to your entire infrastructure.

Chef::Node::ImmutableMash#dup

NOTE: #default and #default= are likely to be pretty confusing. For a
regular ruby Hash, they control what value is returned for, e.g.,
  hash[:no_such_key] #=> hash.default
Of course, 'default' has a specific meaning in Chef-land

Source | Google | Stack overflow

Edit

git clone [email protected]:opscode/chef.git

cd chef

open lib/chef/node/immutable_collections.rb

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Chef--Node--ImmutableMash-dup-for-pr

# Commit to git

git add lib/chef/node/immutable_collections.rbgit commit -m "better docs for Chef::Node::ImmutableMash#dup"

# Open pull request

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

hub fork

git push <your name> -your-name--update-docs-Chef--Node--ImmutableMash-dup-for-pr

hub pull-request

# Celebrate!