  Developer contribution guidelines are used in social coding sites like GitHub
to explain and shape the process a project expects contributors to follow. They
set standards for all participants and "save time and hassle caused by
improperly created pull requests or issues that have to be rejected and
resubmitted" (GitHub). Yet, we lack a systematic understanding of the content
of a typical contribution guideline, as well as the extent to which these
guidelines are followed in practice. Additionally, understanding how guidelines
may impact projects that use Continuous Integration as part of the contribution
process is of particular interest. To address this knowledge gap, we conducted
a mixed-methods study of 53 GitHub projects with explicit contribution
guidelines and coded the guidelines to extract key themes. We then created a
process model using GitHub activity data (e.g., commit, new issue, new pull
request) to compare the actual activity with the prescribed contribution
guidelines. We show that approximately 68% of these projects diverge
significantly from the expected process.
