I’m personally a big fan of code reviews. Proper code review habits can really improve the quality of a code base and help you find bugs or design problems in your project. I also believe that a good tools for code review can improve developers life, so I’m always glad to see new tools or integrations in that field. If you don’t know what code reviews are, please have a look at wikipedia’s description here.

I think it’s already 5 days when Google Project Hosting integrated Code Reviews. I found out yesterday when I watched last commits of the open source projects I’m tracking. When I selected a commit I was surprised to see “Start a code review” block on the right side.

This wiki page on the Google Project Hosting (GPH) support wiki describes in more details how to do code reviews on GPH.

I have been writing about Mondrian (Google’s internal code review tool written by Guido van Rossum) way back.  When Google AppEngine was released, Guido ported most of the functionality of Mondrian into new open source project called Rietveld – Code Review application running on App Engine (Article about Rietveld on AppEngine webpage). Many open source projects are using Rietveld public instance already, you can check that out just by looking into repositories list. Some project use they own instance of Retvield and limits access to code reviews using separate domain with Google Apps for your domain.

You can read more about background behind Rietveld here and how to start code reviews with Rietveld here.

Rietveld is pre-commit code review tool and Google Project Hosting Code Review implementation is post-commit. That is probably the biggest difference between those two. All the shortcuts used in GPH are mostly based on what’s available in Rietveld. So now we have both pre-commit and post-commit code review tools and both are from Google.

Some of the implemented features include review of the whole commit and also writing of in-line comments (in a nice diff view) for particular lines of code.

Configuration of your project code reviews can be found in Administer->Source tab.

Summarizing, we just got another great tool for doing code reviews and it’s nicely integrated into Google Project Hosting. It also means that open source projects don’t have to use ReviewBoard or Rietveld and can start doing code reviews right away if they use SVN repository from Google Project Hosting. If you’re project is using public SVN, but you are more interested in pre-commit code reviews, you can always use Rietveld public instance on Google AppEngine and add your SVN repository to the Rietveld repository list. It’s that simple :-)