Rainer Koschke

Chanchal K. Roy, Minhaz F. Zibran, Rainer Koschke

Duplicated code or code clones are a kind of code smell that have both positive and negative impacts on the development and maintenance of software systems. Software clone research in the past mostly focused on the detection and analysis of code clones, while research in recent years extends to the whole spectrum of clone management. In the last decade, three surveys appeared in the literature, which cover the detection, analysis, and evolutionary characteristics of code clones. This paper presents a comprehensive survey on the state of the art in clone management, with in-depth investigation of clone management activities (e.g., tracing, refactoring, cost-benefit analysis) beyond the detection and analysis. This is the first survey on clone management, where we point to the achievements so far, and reveal avenues for further research necessary towards an integrated clone management system. We believe that we have done a good job in surveying the area of clone management and that this work may serve as a kind of roadmap for future research in the area

Verena Käfer, Stefan Wagner, Rainer Koschke

Having similar code fragments, also called clones, in software systems can lead to unnecessary comprehension, review and change efforts. Syntactically similar clones can often be encountered in practice. The same is not clear for only functionally similar clones (FSC). We conducted an exploratory survey among developers to investigate whether they encounter functionally similar clones in practice and whether there is a difference in their inclination to remove them to syntactically similar clones. Of the 34 developers answering the survey, 31 have experienced FSC in their professional work, and 24 have experienced problems caused by FSCs. We found no difference in the inclination and reasoning for removing FSCs and syntactically similar clones. FSCs exist in practice and should be investigated to bring clone detectors to the same quality as for syntactically similar clones, because being able to detect them allows developers to manage and potentially remove them.