Bad Smells in IEC 61499-based Control Software: Sniffing out Shotgun Surgery

Bad smells are code patterns which have a negative influence on software, often impacting its quality and maintainability. Because of these negative effects, it is important to detect and avoid them. In the domain of software engineering, the topic of bad smells has been widely researched. On the other hand, in the area of industrial automation and PLC programming languages, bad smells have not received the same amount of attention. Shotgun Surgery is a code smell which we can find when a functionality is used in a certain number of places in code. It starts smelling when every change to the functionality requires many smaller changes to the places where it’s used. If we take a closer look at Shotgun Surgery in the domain of IEC 61499, we see that the general trend persists and that there is no adequate research done on it. In this paper, we want to identify Shotgun Surgery scenarios and showcase multiple existing and new approaches for its detection in IEC 61499.