On Indirectly Dependent Documentation in the Context of Code Evolution: A Study

A software system evolves over time due to factors such as bug-fixes, enhancements, optimizations and deprecation. As entities interact in a software repository, the alterations made at one point may require the changes to be reflected at various other points to maintain consistency. However, often less attention is given to making appropriate changes to the documentation associated with the functions. Inconsistent documentation is undesirable, since documentation serves as a useful source of information about the functionality. This paper presents a study on the prevalence of function documentations that are indirectly or implicitly dependent on entities other than the associated function. We observe a substantial presence of such documentations, with 62% of the studied Javadoc comments being dependent on other entities, as studied in 11 open-source repositories implemented in Java. We comprehensively analyze the nature of documentation updates made in 1288 commit logs and study patterns to reason about the cause of dependency in the documentation. Our findings from the observed patterns may be applied to suggest documentations that should be updated on making a change in the repository.