Cleaning up Copy-Paste Clones with Interactive Merging

International audienceCopy-paste-modify is a form of software reuse in which developers explicitly duplicate source code. This duplicated source code, amounting to a code clone, is adapted for a new purpose. Copy-paste-modify is popular among software developers, however, empirical evidence shows that it complicates software maintenance and increases the frequency of bugs. To allow developers to use copy-paste-modify without having to worry about these concerns , we propose an approach that automatically merges similar pieces of code by creating suitable abstractions. Because different kinds of abstractions may be beneficial in different contexts, our approach offers multiple abstraction mechanisms, which were selected based on a study of popular open-source repositories. To demonstrate the feasibility of our approach, we have designed and implemented a prototype merging tool for C++ and evaluated it on a number of code clones exhibiting some variation, i.e near-miss clones, in popular Open Source packages. We observed that maintainers find our algorithmically created abstractions to be largely preferable to the existing duplicated code

DeepClone: Modeling Clones to Generate Code Predictions

Programmers often reuse code from source code repositories to reduce the development effort. Code clones are candidates for reuse in exploratory or rapid development, as they represent often repeated functionality in software systems. To facilitate code clone reuse, we propose DeepClone, a novel approach utilizing a deep learning algorithm for modeling code clones to predict the next set of tokens (possibly a complete clone method body) based on the code written so far. The predicted tokens require minimal customization to fit the context. DeepClone applies natural language processing techniques to learn from a large code corpus, and generates code tokens using the model learned. We have quantitatively evaluated our solution to assess (1) our model’s quality and its accuracy in token prediction, and (2) its performance and effectiveness in clone method prediction. We also discuss various application scenarios for our approach