Clone Merge -- An Eclipse Plugin to Abstract Near-Clone C++ Methods

Abstract

Software clones are prevalent. In the work of Laguë et al. [2], they observe that 6.4% and 7.5% of the source code in different versions of a large, mature code base are clones. The work of Baxter et al. [1] reports even higher numbers, sometimes exceeding 25%. We consider the prevalence of such near miss clones to be strong indicators that copy-paste-modify is a wide-spread development methodology. Even though clones are prevalent, they are a significant development headache. Specially, if bugs arise in one of the clones, they need to be fixed in all of the clones. This problem is acknowledged in the work of Juergens et al. [4] who say in their work that "cloning can be a substantial problem during development and maintenance", since "inconsistent clones constitute a major source of faults". A similar concern is raised in practitioner literature [3] suggesting that clones should be removed in some form or the other. We present a tool that can be installed as a plugin to Eclipse CDT, the development environment for C/C++. The research prototype comes with a refactoring option called "Copy Paste merge" refactoring, which is available as a menu option in the modified version of the Eclipse CDT.