Prediction and Ranking of Co-change Candidates for Clones

Code clones are identical or similar code fragments scattered in a code-base. A group of code fragments that are similar to one another form a clone group. Clones in a particular group often need to be changed together (i.e., co-changed) consis-tently. However, all clones in a group might not require con-sistent changes, because some clone fragments might evolve independently. Thus, while changing a particular clone frag-ment, it is important for a programmer to know which other clone fragments in the same group should be consistently co-changed with that particular clone fragment. In this research work, we empirically investigate whether we can automatically predict and rank these other clone fragments (i.e., the co-change candidates) from a clone group while making changes to a particular clone fragment in this group. For prediction and ranking we automatically retrieve and infer evolutionary coupling among clones by mining the past clone evolution history. Our experimental result on six subject systems written in two different programming lan-guages (C, and Java) considering both exact and near-miss clones implies that we can automatically predict and rank co-change candidates for clones by analyzing evolutionary coupling. Our ranking mechanism can help programmers pinpoint the likely co-change candidates while changing a particular clone fragment and thus, can help us to better manage software clones