Monthly Archives: July 2014

GitMinutes #30: Luca Milanesio on Gerrit Code Review

Posted on by
Reply

git-minutesMany thanks to Thomas Ferris Nicolaisen for inviting me to talk about Gerrit Code Review at GitMinutes.

It has been a very interesting discussion on the benefits of Code Review and how Gerrit can help out small and large companies embracing it.

The interview is available on-line at http://episodes.gitminutes.com/2014/07/gitminutes-30-luca-milanesio-on-gerrit.html, alternatively you can download and listen the 1h 27′ conversation on PodCast at https://itunes.apple.com/de/podcast/gitminutes-podcasts/id637843725?l=en.

Use the force Luca!

We started (of course!) talking about the [in]famous force push of 186 Jenkins repositories to GitHub, I was on the Top-10 HackersNews over 7h … so I was expecting the question to pop-up during the interview 🙂

My friend Alex Blewitt took the opportunity as well to forge a Star-Wars like headline for his InfoQ article on what happened.

Git adoption in the Enterprise, where all began

We moved the discussion to the foundation of my business on Git and Code Review and the reasons and challenges that an Enterprise company is facing when moving to Git. We went through the history on how LMIT started GitEnterprise.com and then focused on Gerrit Code Review based product and services for large Enterprises World-Wide: a niche and successful business nowadays.

GitHub or Gerrit? or both with GerritHub?

As I expected, we ended up comparing GitHub and Gerrit analysing the similarities and differences between the two. This topic has been presented as well in two conferences at Gerrit User Summit @GooglePlex – Mountain View CA and 33rd Degree.org Java Developers Conference in Krakow; slides are available at http://www.slideshare.net/lucamilanesio/gerrit-codereviewgit-hubplugin.

Gerrit has historically been considered as “more difficult” than GitHub: true in the past but not anymore today apart from the Web User-Experience CSS styling, much nicer and pleasent on GitHub. The availability of http://gerrithub.io allowed over 1,800 developers since October 2013 to get started with Gerrit in less than 5 minutes by watching an Gerrit Introductionary YouTube video: using it was then just 3 clicks away, no installation or configuration needed! The availability of an easy and accessible Public Cloud instance represents a big improvement in accessibility and usability of Gerrit.

For which teams is Gerrit the right choice?

We talked about the “typical learning curve” of people coming from previous version control systems, such as Subversion. Does it make sense to get started with Git and Gerrit at the same time? When is Gerrit needed and when is it going to provide most of its value?

I’ve covered the topic in the past webinars and talks: hands-on Webinars recordings are freely available on-line at:

The size of the project (in terms of number of people x number of repositories) is typically one of the key factors in Code Review adoption. Gerrit however can be used as well as a standalone OpenSource Git Server , even without leveraging its Code Review capabilities: this makes the choice of Gerrit a good first step towards a smoother Git adoption.

What are Gerrit Topics about?

We went through a very interesting discussion about “Gerrit Topic”, a feature that is not new to Gerrit but is sometimes forgotten besides its important and relevance for medium-large teams.

With the forthcoming support of multi-repositories atomic commits in Gerrit, it will be possible to merge multiple changes on multiple repositories at the same time for a single topic. This feature is not ready yet but coming hopefully in the near future and Google Gerrit Team developers and contributors are working on it.

The ability to make an atomic commit across multiple repositories will allow to have a more consistent Jenkins build process as well, with less broken builds because of interdependent changes on multiple components.

Who is using Gerrit today?

We talked about the adoption of Gerrit in the community, which is growing year after year. A lot of medium companies adopted Gerrit in the past, including Spotify side-by-side with GitHub.

The ability to “submit a change” to any project without the risk to break the build is definitely an incentive to encourage even more people to contribute to share the knowledge and improve the code base, without the risk of breaking anything or  forking the code. This is one of the reason that drove large OpenSource organisations such as the Eclipse Foundation and OpenStack to the adoption Gerrit Code Review in their tools platform.

How to embrace Code Review in a Team or Company?

We went through an interesting comparison / discussion of Agile Methodology vs. Code Review. Often Teams misunderstand and confuse the concept of “review” with “pair-programming”: the problem was well analysed in my book “Learning Gerrit Code Review” (available on Amazon.com at http://www.amazon.com/Learning-Gerrit-Code-Review-Milanesio/dp/1783289473). I defined the pair-programming as a dot in a time/people space: two developers writing a piece of code at the same time. This however does not exclude all the other points in the time/people space where multiple people at different times will read the code and provide their feedback: pair-programming is then a “specific example” of the “code review space”.

Because of the different perspectives (pair-programming is a dot whilst code-review is a “cloud of dots” in time/people space) they are not one exclusive of the other: they are equally important and both enable effective collective code ownership and knowledge sharing.

References and greetings.

It has been a very long but interesting discussion with Thomas and hope you’ll enjoy it.

See below the links of the resources we mentioned during the interview:

Thanks again to Thomas for his fantastic initiative: GitMinutes PodCast!

Luca Milanesio