The lifecycle of Technical Debt that manifests in both source code and issue trackers

Context: Although Technical Debt (TD) has increasingly gained attention in recent years, most studies exploring TD are based on a single source (e.g., source code, code comments or issue trackers). Objective: Investigating information combined from different sources may yield insight that is more than the sum of its parts. In particular, we argue that exploring how TD items are managed in both issue trackers and software repositories (including source code and commit messages) can shed some light on what happens between the commits that incur TD and those that pay it back. Method: To this end, we randomly selected 3,000 issues from the trackers of five projects, manually analyzed 300 issues that contained TD information, and identified and investigated the lifecycle of 312 TD items. Results: The results indicate that most of the TD items marked as resolved in issue trackers are also paid back in source code, although many are not discussed after being identified in the issue tracker. Test Debt items are the least likely to be paid back in source code. We also learned that although TD items may be resolved a few days after being identified, it often takes a long time to be identified (around one year). In general, time is reduced if the same developer is involved in consecutive moments (i.e., introduction, identification, repayment decision-making and remediation), but whether the developer who paid back the item is involved in discussing the TD item does not seem to affect how quickly it is resolved. Conclusions: Investigating how developers manage TD across both source code repositories and issue trackers can lead to a more comprehensive oversight of this activity and support efforts to shorten the lifecycle of undesirable debt.