The vision of software clone management: Past, present, and future (Keynote paper)

Abstract

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, costbenefit 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 roadmap for future research in the area

SourcererCC

“…Recall has been very difficult for tool developers to measure as it requires knowledge of the clones that exist in a software system [25,24]. Manually inspecting a system for clones is non-trivial.…”

“…These existing techniques have a number of limitations. The novel scalable algorithms [14,15] do not support Type-3 near-miss clones, where minor to significant editing activities might have taken place in the copy/pasted fragments, and therefore miss a large portion of the clones, since there are more Type-3 in the repositories than other types [24,26,30]. Type-3 clones can be the most needed in large-scale clone detection applications [24,19,6].…”

“…The novel scalable algorithms [14,15] do not support Type-3 near-miss clones, where minor to significant editing activities might have taken place in the copy/pasted fragments, and therefore miss a large portion of the clones, since there are more Type-3 in the repositories than other types [24,26,30]. Type-3 clones can be the most needed in large-scale clone detection applications [24,19,6]. While input partitioning can scale existing non-scalable Type-3 detectors, this significantly increases the cumulative runtime, and requires distribution over a large cluster of machines to achieve scalability in absolute runtime [21,31].…”

“…These applications require tools that scale to hundreds of millions of lines of code. However, very few tools can scale to the demands of clone detection in very large code bases [31,24].…”

“…Clones are created when developers reuse code by copy, paste and modify, although clones may be created by a number of other means [25]. Developers need to detect and manage their clones in order to maintain software quality, detect and prevent new bugs, reduce development risks and costs, and so on [25,24]. Clone management and clone research studies depend on quality tools.…”