Bibliographic record
Abstract
Bug fixing and code refactoring are two distinct maintenance actions with different goals. While bug fixing is a corrective change that eliminates a defect from the program, refactoring targets improving the internal quality (i.e., maintainability) of a software system without changing its functionality. Best practices and common intuition suggest that these code actions should not be mixed in a single code change. Furthermore, as refactoring aims for improving quality without functional changes, we would expect that refactoring code changes will not be sources of bugs. Nonetheless, empirical studies show that none of the above hypotheses are necessarily true in practice. In this paper, we empirically investigate the interconnection between bug-related and refactoring code changes using the SmartSHARK dataset. Our goal is to explore how often bug fixes and refactorings co-occur in a single commit (tangled changes) and whether refactoring changes themselves might induce bugs into the system. We found that it is not uncommon to have tangled commits of bug fixes and refactorings; 21% of bug-fixing commits include at least one type of refactoring on average. What is even more shocking is that 54% of bug-inducing commits also contain code refactoring changes. For instance, 10% (652 occurrences) of the Change Variable Type refactorings in the dataset appear in bug-inducing commits that make up 7.9% of the total inducing commits.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.006 | 0.048 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.005 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".