Why Do Automated Builds Break? An Empirical Study

To detect integration errors as quickly as possible, organizations use automated build systems. Such systems ensure that (1) the developers are able to integrate their parts into an executable whole, (2) the testers are able to test the built system, (3) and the release engineers are able to leverage the generated build to produce the upcoming release. The flipside of automated builds is that any incorrect change can break the build, and hence testing and releasing, and (even worse) block other developers from continuing their work, delaying the project even further. To measure the impact of such build breakage, this empirical study analyzes 3,214 builds produced in a large software company over a period of 6 months. We found a high ratio of build breakage (17.9%), and also quantified the cost of such build breakage as more than 336.18 man-hours. Interviews with 28 software engineers from the company helped to understand the circumstances under which builds are broken and the effects of build breakages on the collaboration and coordination of teams. We quantitatively investigated the main factors impacting build breakage and found that build failures correlate with the number of simultaneous contributors on branches, the type of work items performed on a branch, and the roles played by the stakeholders of the builds (for example developers vs. Integrators).