A Method to Detect License Inconsistencies in Large-Scale Open Source Projects

Wu, Yuhao; Manabe, Yuki; Kanda, Takahiro; Germán, Daniel M.; Inoue, Katsuro

doi:10.1109/msr.2015.37

Cited by 27 publications

(15 citation statements)

References 21 publications

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“…They investigated the extent to which terms of the licenses were adhered during the cloning of these code fragments. Similarly, Wu et al [31] found that cloned files have a potential to be inconsistent in terms of licenses (e.g., one has a license, while the other does not). The paper describes the types of inconsistencies and illustrates the problem and the difficulty to resolve it through an empirical study of Debian 7.5.…”

Section: B Empirical Studies On Licenses Adoption and Evolutionmentioning

confidence: 97%

When and why developers adopt and change software licenses

Vendome

Linares‐Vásquez

Bavota

et al. 2015

2015 IEEE International Conference on Software Maintenance and Evolution (ICSME)

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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.

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Section: B Empirical Studies On Licenses Adoption and Evolutionmentioning

confidence: 97%

When and why developers adopt and change software licenses

Vendome

Linares‐Vásquez

Bavota

et al. 2015

2015 IEEE International Conference on Software Maintenance and Evolution (ICSME)

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“…Vendome et al [10] studied on common understandings among developers on the reason and timing for changing a license, through interviews of developers. Wu et al [11] proposed a method to detect license inconsistencies in a large-scale OSS. As a result of an experiment using Debian v7.8.0, license inconsistencies were detected for Debian v7.8.0.…”

Section: License Compliancementioning

confidence: 99%

Hierarchical Clustering of OSS License Statements toward Automatic Generation of License Rules

Higashi

Ohira

Kashiwa

et al. 2019

Journal of Information Processing

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Reusing open source software (OSS) components for one's own software products has become common in the modern software development. Automated license identification tools have been proposed to help developers identify OSS licenses, since a large number of licenses sometimes must be checked before attempting to reuse. Of the existing tools, Ninka [1] can most correctly identify licenses of each source file by using regular expressions. In case Ninka does not have license identification rules for unknown licenses, Ninka reports these as "unknown licenses" which must be checked by developers manually. Since completely-new or derived OSS licenses appear nearly every year, a license identification tool should be appropriately maintained by adding regular expressions corresponding to the new licenses. The final goal of our study is to construct a method to automatically create candidate license rules to be added to a license identification tool such as Ninka. Toward achieving the goal, files identified as unknown licenses must be classified by license firstly. In this paper, we propose a hierarchical clustering which divides unknown licenses into clusters of files with a single license. We conduct a case study to confirm the usefulness of our clustering method when it is applied for classifying 2,801, 1,230 and 2,446 unknown license statement files for Linux Kernel v4.4.6, FreeBSD v10.3.0 and Debian v7.8.0 respectively. As a result, it is confirmed that our method can create clusters which are suitable as candidates for generating license rules automatically.

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“…To explore empirically this hypothesis, based on what has been done in previous research [8,12,21,22], this study focuses on four types of legal restrictions that may be applied to the free and open source code. The first relates to whether the source code is "restrictive", requiring derivative works to be released under the same license in case of redistribution [19]; the second, to whether it is "highly restrictive", which besides being restrictive, forbids the source code to be even mingled for compilation with software of a different license [19]; the third, to whether the code may be relicensed, meaning that "any distributor has the right to grant a license to the software […] directly to third parties" ( [7], p. 88); and the fourth, to whether a project is licensed under the Academic Free License, since it was written to correct problems of important licenses such as MIT and BSD [7] and is understudied.…”

Section: The Choice Of License and Fsp Successmentioning

confidence: 99%

Changes in free and open source software licenses: managerial interventions and variations on project attractiveness

Santos

2017

J Internet Serv Appl

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The license adopted by an open source software is associated with its success in terms of attractiveness and maintenance of an active ecosystem of users, bug reporters, developers, and sponsors because what can and cannot be done with the software and its derivatives in terms of improvement and market distribution depends on legal terms there specified. By knowing this licensing effect through scientific publications and their experience, project managers became able to act strategically, loosening up the restrictions associated with their source code due to sponsor interests, for example; or the contrary, tightening restrictions up to guarantee source code openness, adhering to the "forever free" strategy. But, have project managers behaved strategically like that, changing their projects license? Up to this paper, we did not know if and what types of changes in these legal allowances project managers have made and, more importantly, whether such managerial interventions are associated with variations in intervened project attractiveness (i.e., related to their numbers of web hits, downloads and members). This paper accomplishes these two goals and demonstrates that: 1) managers of free and open source software projects do change the distribution rights of their source code through a change in the (group of) license(s) adopted; and 2) variations in attractiveness are associated with the strategic choice of a licensing schema. To reach these conclusions, a unique dataset of open source projects that have changed license was assembled in a comparative form, analyzing intervened projects over its monthly periods of different licenses. Based on a sample of more than 3500 active projects over 44 months obtained from the FLOSSmole repository of Sourceforge.net data, 756 projects that had changed their source code distribution allowances and restrictions were identified and analyzed. A dataset on these projects' type of changes was assembled to enable a descriptive and exploratory analysis of the types of license interventions observed over a period of almost four years anchored on projects' attractiveness. More than 35 types of interventions were detected. The results indicate that variations in attractiveness after a license intervention are not symmetric; that is, if a change from license schema A to B is beneficial to attractiveness, a change from B to A is not necessarily prejudicial. This and other interesting findings are discussed in detail. In general, the results here reported support the current literature knowledge that the restrictions imposed by the license on the source code distribution are associated with market success vis-a-vis project attractiveness, but they also suggest that the state-of-the-science is superficial in terms of what is known about why these differences in attractiveness can be observed. The complexity of the results indicates to free software managers that no licensing schema should be seen as the right one, and its choice should be carefully made, considering project strat...

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A Method to Detect License Inconsistencies in Large-Scale Open Source Projects

Cited by 27 publications

References 21 publications

When and why developers adopt and change software licenses

When and why developers adopt and change software licenses

Hierarchical Clustering of OSS License Statements toward Automatic Generation of License Rules

Changes in free and open source software licenses: managerial interventions and variations on project attractiveness

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