Stack Overflow: A Code Laundering Platform?

TL;DR

This study investigates whether developers respect licensing terms when reusing code from Stack Overflow, revealing numerous potential license violations and highlighting ethical concerns in code sharing practices.

Contribution

The paper provides the first empirical analysis of license compliance issues related to code reuse between Stack Overflow and Android apps.

Findings

Identified 232 code snippets potentially reused from Stack Overflow in Android apps.

Detected 1,226 Stack Overflow posts that are clones of code in Android apps.

Found 1,279 cases of potential license violations involving code reuse and posting.

Abstract

Developers use Question and Answer (Q&A) websites to exchange knowledge and expertise. Stack Overflow is a popular Q&A website where developers discuss coding problems and share code examples. Although all Stack Overflow posts are free to access, code examples on Stack Overflow are governed by the Creative Commons Attribute-ShareAlike 3.0 Unported license that developers should obey when reusing code from Stack Overflow or posting code to Stack Overflow. In this paper, we conduct a case study with 399 Android apps, to investigate whether developers respect license terms when reusing code from Stack Overflow posts (and the other way around). We found 232 code snippets in 62 Android apps from our dataset that were potentially reused from Stack Overflow, and 1,226 Stack Overflow posts containing code examples that are clones of code released in 68 Android apps, suggesting that developers may have copied the code of these apps to answer Stack Overflow questions. We investigated the licenses of these pieces of code and observed 1,279 cases of potential license violations (related to code posting to Stack overflow or code reuse from Stack overflow). This paper aims to raise the awareness of the software engineering community about potential unethical code reuse activities taking place on Q&A websites like Stack Overflow.