Most of Mozilla gathered in Orlando in December for an all hands meeting. If you attended any of the plenary sessions, you probably heard people like David Bryant and Lawrence Mandel make references to improving the Firefox build system and related tools. Well, the cat is out of the bag: Mozilla will be investing heavily in the Firefox build system and related tooling in 2016!

In the past 4+ years, the Firefox build system has mostly been held together and incrementally improved by a loose coalition of people who cared. We had a period in 2013 where a number of people were making significant updates (this is when moz.build files happened). But for the past 1.5+ years, there hasn't really been a coordinated effort to improve the build system - just a lot of one-off tasks and (much-appreciated) individual heroics. This is changing.

Improving the build system is a high priority for Mozilla in 2016. And investment has already begun. In Orlando, we had a marathon 3 hour meeting planning work for Q1. At least 8 people have committed to projects in Q1.

The focus of work is split between immediate short-term wins and longer-term investments. We also decided to prioritize the Firefox and Fennec developer workflows (over Gecko/Platform) as well as the development experience on Windows. This is because these areas have been under-loved and therefore have more potential for impact.

Here are the projects we're focusing on in Q1:

• Turnkey artifact based builds for Firefox and Fennec (download pre-built binaries so you don't have to spend 20 minutes compiling C++)
• Running tests from the source directory (so you don't have to copy tens of thousands of files to the object directory)
• Speed up configure / prototype a replacement
• Telemetry for mach and the build system
• NSPR, NSS, and (maybe) ICU build system rewrites
• mach build faster improvements
• Improvements to build rules used for building binaries (enables non-make build backends)
• mach command for analyzing C++ dependencies
• Deploy automated testing for mach bootstrap on TaskCluster

Work has already started on a number of these projects. I'm optimistic 2016 will be a watershed year for the Firefox build system and the improvements will have a drastic positive impact on developer productivity.