Concepts, Operations, and Feasibility of a Projection-Based Variation Control System

Highly configurable software often uses preproces-
sor annotations to handle variability. However, understanding,
maintaining, and evolving code with such annotations is difficult,
mainly because a developer has to work with all variants at a
time. Dedicated methods and tools that allow working on a subset
of all variants could ease the engineering of highly configurable
software. We investigate the potential of one kind of such tools:
projection-based variation control systems. For such systems we
aim to understand: (i) what end-user operations they need to
support, and (ii) whether they can realize the actual evolution
of real-world, highly configurable software. We conduct an
experiment that investigates variability-related evolution patterns
and that evaluates the feasibility of a projection-based variation
control system by replaying parts of the history of a highly
configurable real-world 3D printer firmware project. Among
others, we show that the prototype variation control system does
indeed support the evolution of a highly configurable system and
that in general, it does not degrade the code.