Gerrit

http://lwn.net/Articles/359489/

The Gerrit story starts with the progressive escape of an in-house Google process and tool.

When Guido van Rossum, creator of the Python language, began working at Google in 2005, he started developing a tool, in Python naturally, to coordinate code reviews. The result, called Mondrian, lets users view the proposed change as a side-by-side comparison, and participate in comment threads attached anywhere in the code under review. An overview page shows a to-do list of incoming changes to review and reviewers' comments.