Development version numbers

Now that I am switching to release branches I am finally going to also tackle something that has always bothered me but I’ve never taken the time to solve: the development source code has the same version number as the most recent release. I have always wanted it to be some sort of automated number, but I wasn’t sure what I wanted it to be. And I didn’t want to have to update it myself with every single commit.

At first I had wondered about a number that gets incremented every time you compile the project, but I quickly realized that was a pointless thing to track. I may build a project 5,000 times and have a huge build number, but someone else might download the source and compile it only twice. Same source code, different version number. That’s frankly pretty silly.

Instead, I got inspired by the idea of using the git revision ID. It is obviously unique for each commit, and it identifies the specific source code for everyone. Of course, you can’t embed the revision ID because it is a hash that is created of the source code that you’re trying to embed it in. A hash that contains itself? Impossible! Of course, all you have to do instead is simply ask git for the revision ID, and pass that as a definition to the compiler:

VERSION = $$system(git rev-parse --short HEAD)
DEFINES += VERSIONSTR=\\\"git.$${VERSION}\\\"

The source code also needs to make use of the new compiler definition:

QCoreApplication::setApplicationVersion(VERSIONSTR);

This means that I finally have an automated version number for the development source code. I’ve only updated Kapow so far, but I am going to make this change to all of my projects.