Can feature requests reveal the refactoring types?

Software refactoring is the process of improving the design of a software system while preserving its external behavior. In recent years, refactoring research has been growing as a response to the degradation of software quality. Recent studies performed an in-depth investigation in (1) how refactoring practices are taking place during the software evolution, (2) how to recommend refactoring to improve the design of software, and (3) what type of refactoring operations can be implemented. However, there is a lack of support when it comes to developers’ typical programming tasks, including feature updates and bug fixes. The goal of this thesis is to investigate whether it is possible to support the developer through recommending appropriate refactoring types to be performed when the developer is assigned a given issue to handle. Our proposed solution will take as input the text of the issue along with the source code and tries to protect the appropriate refactoring type that would help in adapting efficiently the existing source code to the given feature request. To do so, we rely on the use of supervised learning. We start with collecting various issues that were handled using refactoring. This data will be used to train a model that will be able to predict the appropriate refactoring, given as input an Open issue description. We design a classification model that inputs a feature request and suggests a method-level refactoring. The classification model was trained with a total of 4008 feature request examples of four refactoring types. Our initial results show that this solution suffers from several challenges including the class imbalance: not all refactoring types are equally used to handle issues. Another challenge we detected is related to the description of the issue itself which typically does not explicitly mention any potential refactoring. Therefore, there will be a need for a large set of issues to be able to appropriately learn any patterns among them that would discriminate towards a given refactoring type