When and why developers adopt and change software licenses

Abstract

Software licenses legally govern the way in which developers can use, modify, and redistribute a particular system. While previous studies either investigated licensing through mining software repositories or studied licensing through FOSS reuse, we aim at understanding the rationale behind developers' decisions for choosing or changing software licensing by surveying open source developers. In this paper, we analyze when developers consider licensing, the reasons why developers pick a license for their project, and the factors that influence licensing changes. Additionally, we explore the licensing-related problems that developers experienced and expectations they have for licensing support from forges (e.g., GitHub).Our investigation involves, on one hand, the analysis of the commit history of 16,221 Java open source projects to identify the commits where licenses were added or changed. On the other hand, it consisted of a survey-in which 138 developers informed their involvement in licensing-related decisions and 52 provided deeper insights about the rationale behind the actions that they had undertaken. The results indicate that developers adopt licenses early in the project's development and change licensing after some period of development (if at all). We also found that developers have inherent biases with respect to software licensing. Additionally, reuse-whether by a non-contributor or for commercial purposes-is a dominant reason why developers change licenses of their systems. Finally, we discuss potential areas of research that could ameliorate the difficulties that software developers are facing with regard to licensing issues of their software systems.

On the Detection of Licenses Violations in the Android Ecosystem

“…This finding is consistent with observations made by Vendome et al [7] that developers tend to delay their decision about license selection. Regarding transitions from a known license to NONE or UNKNOWN license, …”

“…Although we only conduct our case study with 857 mobile apps from the F-droid market, most of our findings are consistent with previous studies (e.g., [7]). We share our data and scripts at:…”

“…In fact, studies made by Vendome and al. [7] have shown that developers have a limited knowledge on licensing issues. In the following chapter we will investigate license violations in more details.…”

“…Also, their analysis were limited to java projects from Github. In a follow up study [7] the authors conducted a survey to understand when and why developers adopt and change licenses. They found that developers have some difficulties in dealing with license terms e.g.,with incompatible licenses, and that they change licenses toward more permissive licenses to facilitate the reuse of their product in commercial systems.…”

“…These two licenses are therefore incompatibles and any software system that contains components under these two licenses (at the same time) is exposed to penalties [5] With the very high speed of apps development (on average 2,371 new apps are published in Google Play [6] every day), developers are increasingly inclined to reuse code from other open source projects. Vendome et al [7] who investigated how developers of open-source projects adopt and change licenses found that these developers often experience difficulties understanding licensing terms. These factors combined with the large number of available licenses (i.e., more than 70 open source licences exist today [3]) that developers could choose from, makes license violations very likely.…”