A Preliminary Study of GitHub Actions Workflow Changes

CI/CD practices play a significant role in collaborative software development. The GitHub social coding platform introduced GitHub Actions as a way to automate different aspects of software production such as testing, building, quality checking, dependency and security management. We report on preliminary findings of a quantitative analysis on how GitHub Actions workflows are being changed over time. The study is based on a dataset of 22,733 GitHub repositories containing 4 million weekly snapshots of workflow files from November 2019 to September 2022. First, we analyse the coarse-grained changes being made to workflows, including when repositories start using them, when they are being added, modified, renamed and removed. Second, we analyse changes made to workflow code, including how many code lines are changed and what types of changes are being made to them. The findings of this quantitative analysis provide preliminary insights on how GitHub Actions workflows are being changed over time, and whether they adhere to the evolution laws of continuing growth and continuing change. It paves the way for studying more evolution laws, as well as more in-depth analyses on the types of changes that CI/CD workflows are subject to as well as the reasons for these changes.