While at GTAC I started participating in the discussion about the new webdriver/selenium merger, specifically on the Ruby side of it. Not to be left out, I offered to contribute the code for the gem so I dived in and started looking at the code that goes in the gem.
Webdriver (and selenium) are not pure Ruby projects, so their structure deviates from the convenient convention of the bin/ lib/ test/ directories. Code is organized by component (common, chrome, ie, firefox etc.) so the Ruby code lives in different directories. Now the two tools for gem generation that I know and have used (hoe and jeweler) live in a world of pure Ruby projects. Not only that, they live in a world where there is only one gem per project.
Time to specify a couple of requirements. Projects like webdriver need a way to create multiple gems (in this case one gem per OS platform - windows, macosx, linux) from a directory structure that does not conform to the conventions used in Ruby projects. Additionally, whichever tool is used to create the gems needs to keep it's Rake tasks nicely namespaced (jeweler adds a rake task named 'build'. In a project that has C or java code build has a well established and completely different meaning).
So I guess I have opened Aeolus' sack and the winds are going to take me into code unknown. I am reluctant to start another tool (why rewrite code that interfaces with Gemcutter and Rubyforge when all I need is an extension) so I have contacted Josh Nichols (the creator of jeweler) to see if we can extend jeweler and cover these cases.