rails/rails — pull request #8571 by khozlov (2012-12-20 15:19:07+00:00)
Title: Fixed ActiveSupport inflector underscore regex

The inflector underscore regex was not matching nested acronyms, which causes problems for mixed-case acronyms (i.e. calling `#underscore` on `"HTTP::RESTful"` with a `"RESTful"` acronym).