Characterizing Implicit Communal Components as Technical Debt in Automotive Software Systems

Automotive software systems are often characterized by a set of features that are implemented through a network of communicating components. It is common practice to implement or adapt features by an ad hoc (re) use of signals that originate from components of another feature. Thereby, over time some components become so-called implicit communal components. These components increase the necessary efforts for several development activities because they introduce feature dependencies. Refactoring implicit communal components reduces these efforts but also costs refactoring effort. In this paper, we provide empirical evidence that implicit communal components exist in industrial automotive systems. For two cases, we show that less than 10% of the components are responsible for more than 90% of the feature dependencies. Secondly, we propose a refactoring approach for implicit communal components, which makes them explicit by moving them to a dedicated platform component layer. Finally, we characterize implicit communal components as technical debt, which is a metaphor for suboptimal solutions having short-term benefits but causing a long-term negative impact. With this metaphor, we describe the trade-off between accepting the negative effects of implicit communal components and spending the necessary refactoring costs.