Fault triggers in open-source software: An experience report

With software systems becoming increasingly large and complex, many difficulties in coping with software bugs arise for developers. Despite good development practices, thorough testing, and proper maintenance policies, a non-negligible number of bugs remain in the released software. Understanding the type of residual bugs is fundamental for adopting proper countermeasures in current and future software releases. Depending on the fault triggering conditions that lead to a failure, developers can introduce fault-tolerance mechanisms and plan verification and validation strategies. In this paper, we analyze bugs in four large open-source software systems during their lifecycle, based on the concept of fault triggers. We first investigate how the type of system affects the bug type proportions, and their evolution over years. Then, an analysis of bug subtypes is performed, so as to better understand their nature, followed by a comparison with respect to attributes such as their average time to fix and severity.