adding requires and default yaml parser to psych if possible
It's a very bad idea to add 'psych' instead of default 'syck' for 'yaml'. I have an issue with this in bundler 1.0.10 and ruby 1.9.2 because psych has a big issue with aliased sections in yaml. Now, to fix it, I should do require 'yaml' before require 'bunler' in rails-script.
See https://gist.github.com/809309 for reproduce. I've created bug https://github.com/carlhuda/bundler/issues/issue/1010
This commit changes the default YAML parser to Psych for all gems, which may introduce subtle breakage. I personally ran into this in Rails 2.3: https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/6354-psych-does-not-handle-symbols-in-yaml-used-in-activesupport
I'm not sure if this is a Bundler issue, or if any problems should be reported to the application or Psych. FWIW, Rails 3.0 seems to have worked around it, so I assume they acknowledge it to be an issue there, and I've reported one for 2.3.
Is it possible that 'psych' is breaking the YAML output of ".bundle/config"?
It appears to us that between 1.0.9 and 1.0.10, the command "bundle install --deployment" has been broken, and no longer writes to ".bundle/config".
It could be an issue with our server configuration though, so it would be great to have this verified by someone else.