Copy and paste redeemed

Abstract

Software evolves continuously. As software evolves, it's code bases require implementations of new features. These new functionalities are sometimes mere extensions of existing functionalities with minor changes. A commonly used method of extending an existing feature into a similar new feature is to copy the existing feature and modify it. This method of extending feature is called “Copy-paste-modify”. Another method of achieving the same goal of extending existing feature into similar feature is abstracting the multiple similar features into one common feature with appropriate selectors that enable choosing between the features. The advantages of the “Copy-paste-modify” technique range from speed of development to reduced possibility of breaking existing feature. The advantages of abstraction vary from user preference to have abstracted code to long term maintenance benefits. In our paper, we describe an informal poll and discuss related work to confirm our beliefs about the advantages of each method of extending features. We observe a potential compromise while developers extend features which are near-clones of existing features. We propose to address this dilemma by coming up with a novel approach that can semi-automatically abstract nearclone features and evaluate our approach by building a prototype in C++ and abstracting near-clone methods in popular open source repositories.