Towards open source software licenses compatibility check

The use of free and open source software is increasing and there is currently a tendency towards more openness in the provision of open source software. However, libraries that are used in conjunction with the software may affect the final license selection of the open source software and special caution is needed by software developers. Existing tools provide the means to extract license information from software projects, but this information has not been utilized towards recommending licenses that do not cause license violations. In this paper, we present our work towards the recommendation of licenses that satisfy the license compatibility requirement taking into consideration the licenses of third party libraries used in the software project. We have employed a dataset of 160 open source software projects to compare license compatibility using license extraction techniques implemented in different tools, i.e. Nomos and Ninka, whereas we have integrated the license extraction process in the findOSSLicense open source license recommender system, in order to recommend licenses that do not cause violations. The evaluation results and a small scale user study demonstrate the added value of the approach for the software developers in being better informed about license compatibility.