21st Century C, 2nd Edition

Chapter 4. Version Control

Look at the world through your Polaroid glasses

Things’ll look a whole lot better for the working classes.

Gang of Four, “I Found that Essence Rare”

This chapter is about revision control systems (RCSes), which maintain snapshots of the many different versions of a project as it develops, such as the stages in the development of a book, a tortured love letter, or a program.

Using an RCS has changed how I work. To explain it with a metaphor, think of writing as rock climbing. If you’re not a rock climber yourself, you might picture a solid rock wall and the intimidating and life-threatening task of getting to the top. But in the modern day, the process is much more incremental. Attached to a rope, you climb a few meters, and then clip the rope to the wall using specialized equipment (cams, pins, carabiners, and so on). Now, if you fall, your rope will catch at the last carabiner, which is reasonably safe. While on the wall, your focus is not reaching the top, but the much more reachable problem of finding where you can clip your next carabiner.

Coming back to writing with an RCS, a day’s work is no longer a featureless slog toward the summit, but a sequence of small steps. What one feature could I add? What one problem could I fix? Once a step is made and you are sure that your code base is in a safe and clean state, commit a revision, and if your next step turns out disastrously, you can fall back to the revision you just committed instead of starting ...