GranulRef

Tool to transform repository commit history into different granularities and detect refactorings.

Coarse-grained Refactoring & Ephemeral Refactoring

Coarse-grained Refactoring (CGR): A refactoring whose code changes are recorded across multiple commits, rather than confined in a single commit.

Ephemeral Refactoring (EPR): A refactoring whose code changes are recorded within a single commit and where modifications in adjacent commits would disrupt their integrity.

Refactoring Detection

Refactoring detection tool used is RefactoringMiner3.0.4

Usage

1. Remove Comment

python3 remove_comment.py -s <repo_path> -t <output_path_for_comment_removed_repo>

2. Detect Refactoring

python3 command.py -r  -r <path_for_comment_removed_repo> -c <granularity_level> -o <output_dir_for_ref>

3. Trace Refactoring

python3 trace.py -f <output_dir_for_ref> -r  <output_path_for_comment_removed_repo/.git>

4. Collect CGR & EPR for repository

python3 coarse_fine_ref_extractor.py -p <output_dir_for_ref> -c <output_path_for_comment_removed_repo> -r <repo_name>

An example of extraction on repository mbassador

# clone repository
git clone git@github.com:bennidi/mbassador.git
# remove comments
python3 remove_comment.py -s ./mbassador -t ./mbassador_cr
# detect refactorings from granularity level 1 to 5
python3 command.py -r ./mbassador_cr -c 1 -o ./mbassador_refs
python3 command.py -r ./mbassador_cr -c 2 -o ./mbassador_refs
python3 command.py -r ./mbassador_cr -c 3 -o ./mbassador_refs
python3 command.py -r ./mbassador_cr -c 4 -o ./mbassador_refs
python3 command.py -r ./mbassador_cr -c 5 -o ./mbassador_refs
# trace refactorings
python3 trace.py -f ./mbassador_refs -r  ./mbassador_cr/.git
# colect CGR & EPR for repository
python3 coarse_fine_ref_extractor.py -p ./mbassador_refs -c ./mbassador_cr -r mbassador

Publications

The following articles include the details of CGR and EPR.

Lei Chen, Shinpei Hayashi. An Empirical Study on the Impact of Change Granularity in Refactoring Detection. Journal of Systems and Software. 2025.

Lei Chen, Shinpei Hayashi. Impact of Change Granularity in Refactoring Detection. In Proceedings of the 30th IEEE/ACM International Conference on Program Comprehension (ICPC 2022), Early Research Achievements (ERA) Track, pp. 565-569. Online, may, 2022

📖 Read on arXiv 🎥 Watch video

@article{
  title={An Empirical Study on the Impact of Change Granularity in Refactoring Detection},
  author={Chen, Lei and Hayashi, Shinpei},
  journal={Journal of Systems and Software},
  pages={565--569},
  volume={231},
  pages={112608},
  year={2026},
}

@inproceedings{
  title={Impact of change granularity in refactoring detection},
  author={Chen, Lei and Hayashi, Shinpei},
  booktitle={Proceedings of the 30th IEEE/ACM International Conference on Program Comprehension},
  pages={565--569},
  year={2022}
}