An Empirical Study on the Characteristics of Python Fine-Grained Source Code Change Types

Software has been changing during its whole life cycle. Therefore, identification of source code changes becomes a key issue in software evolution analysis. However, few current change analysis research focus on dynamic language software. In this paper, we pay attention to the fine-grained source code changes of Python software. We implement an automatic tool named PyCT to extract 77 kinds of fine-grained source code change types from commit history information. We conduct an empirical study on ten popular Python projects from five domains, with 132294 commits, to investigate the characteristics of dynamic software source code changes. Analyzing the source code changes in four aspects, we distill 11 findings, which are summarized into two insights on software evolution: change prediction and fault code fix. In addition, we provide direct evidence on how developers use and change dynamic features. Our results provide useful guidance and insights for improving the understanding of source code evolution of dynamic language software.