Build automation tools and package managers have a profound influence on software development. They facilitate the reuse of third-party libraries, support a clear separation between the application's code and its external dependencies, and automate several software development tasks. However, the wide adoption of these tools introduces new challenges related to dependency management. In this paper, we propose an original study of one such challenge: the emergence of bloated dependencies.
Bloated dependencies are libraries that the build tool packages with the application's compiled code but that are actually not necessary to build and run the application. This phenomenon artificially grows the size of the built binary and increases maintenance effort. We propose a tool, called DepClean, to analyze the presence of bloated dependencies in Maven artifacts. We analyze 9,639 Java artifacts hosted on Maven Central, which include a total of 723,444 dependency relationships. Our key result is that 75.1% of the analyzed dependency relationships are bloated. In other words, it is feasible to reduce the number of dependencies of Maven artifacts up to 1/4 of its current count. We also perform a qualitative study with 30 notable open-source projects. Our results indicate that developers pay attention to their dependencies and are willing to remove bloated dependencies: 18/21 answered pull requests were accepted and merged by developers, removing 131 dependencies in total.
We study the evolution and impact of bloated dependencies in a single software ecosystem: Java/Maven. Bloated dependencies are third-party libraries that are packaged in the application binary but are not needed to run the application. We analyze the history of 435 Java projects. This historical data includes 48,469 distinct dependencies, which we study across a total of 31,515 versions of Maven dependency trees. Bloated dependencies steadily increase over time, and 89.02% of the direct dependencies that are bloated remain bloated in all subsequent versions of the studied projects. This empiri…
Reusing software libraries is a pillar of modern software engineering. In 2022, the average Java application depends on 40 third-party libraries. Relying on such libraries exposes a project to potential vulnerabilities and may put an application and its users at risk. Unfortunately, research on software ecosystems has shown that the number of projects that are affected by such vulnerabilities is rising. Previous investigations usually reason about dependencies on the dependency level, but we believe that this highly inflates the actual number of affected projects. In this work, we study the ef…
Contemporary software is characterized by reuse of components that are declared as dependencies and that are received from package managers/registries, such as, NPM, PyPI, RubyGems, Maven Central, etc. Direct and indirect dependency relations often form opaque dependency networks, that sometimes lead to conflicting software licenses within these. In this paper, we study license use and license incompatibilities between all components from seven package registries (Cargo, Maven, NPM, NuGet, Packagist, PyPI, RubyGems) with a closer investigation of license incompatibilities caused by the GNU Aff…
As a rich source of data, Call Graphs are used for various applications including security vulnerability detection. Despite multiple studies showing that Call Graphs can drastically improve the accuracy of analysis, existing ecosystem-scale tools like Dependabot do not use Call Graphs and work at the package-level. Using Call Graphs in ecosystem use cases is not practical because of the scalability problems that Call Graph generators have. Call Graph generation is usually considered to be a "full program analysis" resulting in large Call Graphs and expensive computation. To make an analysis ap…
The Maven Dependency Graph: a Temporal Graph-based Representation of Maven Central
Maven Central Repository提供了一个非凡的数据源，可以理解Java应用程序中的复杂架构和演化现象。截至2018年9月6日，该存储库包括280万个工件（用基于JVM的语言实现的编译代码），每个工件都具有元数据的特征，例如确切的版本，上传日期和对其他工件的依赖关系列表。今天，想要分析Maven工件及其依赖关系的完整生态系统的人面临着两个关键挑战：（i）这是一个巨大的数据集;（ii）工件之间的依赖关系没有显式建模，无法查询。在本文中，我们提出了Maven依赖图。这个开放的源数据集提供了两个贡献：2018年9月6日拍摄的整个Maven Central的快照，存储在一个图形数据库中，我们在其中显式地建模所有依赖关系;一个开源基础设施来查询这个巨大的数据集。
Hyrum's law states a common observation in the software industry: "With a sufficient number of users of an API, it does not matter what you promise in the contract: all observable behaviors of your system will be depended on by somebody". Meanwhile, recent research results seem to contradict this observation when they state that "for most APIs, there is a small number of features that are actually used". We investigate this seeming paradox between the observations in industry and the research literature, with a large scale empirical study of client API relationships in one single ecosystem: Ma…
Third-party libraries (TPLs) are frequently reused in software to reduce development cost and the time to market. However, external library dependencies may introduce vulnerabilities into host applications. The issue of library dependency has received considerable critical attention. Many package managers, such as Maven, Pip, and NPM, are proposed to manage TPLs. Moreover, a significant amount of effort has been put into studying dependencies in language ecosystems like Java, Python, and JavaScript except C/C++. Due to the lack of a unified package manager for C/C++, existing research has only…
Background: Modern software uses many third-party libraries and frameworks as dependencies. Known vulnerabilities in these dependencies are a potential security risk. Software composition analysis (SCA) tools, therefore, are being increasingly adopted by practitioners to keep track of vulnerable dependencies. Aim: The goal of this study is to understand the difference in vulnerability reporting by various SCA tools. Understanding if and how existing SCA tools differ in their analysis may help security practitioners to choose the right tooling and identify future research needs. Method: We pres…
