We developed a plugin for IntelliJ IDEA called AntiCopyPaster, which tracks the pasting of code fragments inside the IDE and suggests the appropriate Extract Method refactoring to combat the propagation of duplicates. Unlike the existing approaches, our tool is integrated with the developer’s workflow, and pro-actively recommends refactorings. Since not all code fragments need to be extracted, we develop a classification model to make this decision. When a developer copies and pastes a code fragment, the plugin searches for duplicates in the currently opened file, waits for a short period of time to allow the developer to edit the code, and finally inferences the refactoring decision based on a number of features.

Our experimental study on a large dataset of 18,942 code fragments mined from 13 Apache projects shows that AntiCopyPaster correctly recommends Extract Method refactorings with an F-score of 0.82. Furthermore, our survey of 59 developers reflects their satisfaction with the developed plugin’s operation. The plugin and its source code are publicly available on GitHub at https://github.com/JetBrains-Research/anti-copy-paster. The demonstration video can be found on YouTube: https://www.youtube.com/watch?v=_wwHg-qFjJY.

Eman Abdullah AlOmar

Stevens Institute of Technology

United States

Anton Ivanov

HSE University

Zarina Kurbatova

JetBrains Research

Russia

Yaroslav Golubev

JetBrains Research

Serbia

Mohamed Wiem Mkaouer

Rochester Institute of Technology

United States

Ali Ouni

ETS Montreal, University of Quebec

Canada

Timofey Bryksin

JetBrains Research

Cyprus

Le Nguyen

Rochester Institute of Technology

Amit Kini

Rochester Institute of Technology

Aditya Thakur

Rochester Institute of Technology