Update Propagation Practices in Highly Reusable Open Source Components

In today’s business and software arena, more and more companies are adopting open source software. An example of this rising phenomenon is to base software products on highly reusable open source components. In this scenario, the evolution of the software product is coupled with the evolution of the open source component. A common assumption is that component updates are immediately and regularly propagated to the project. This paper investigates this assumption empirically by studying update propagation practices in two popular open source libraries, zlib and FFmpeg. For each library, we analyze various repository sources with information such as bug reports, revision history, and source code. The results of the case studies suggest that update propagation is subject to several technical and non-technical factors including the way the open source library is used, the extent to which updates are documented, and the degree of community involvement. Based on these findings, we propose a set of recommendations that would allow better follow-up of updates and smoother update propagation.