Software architecture is the abstraction of a software system, that significantly influences software development and maintenance. As software evolves, continuous changes could deviate its architecture from the original design, leading to architecture degradation that causes a decline in software quality. Architecture refactoring becomes necessary to address or mitigate architecture degradation for improving overall quality. Although researchers have developed various architecture refactoring tools and techniques, there has been limited research on how architecture refactoring is practiced in real-world scenarios. In this paper, we conducted an empirical study by analyzing posts from Stack Overflow to understand architecture refactoring in practice. Through our analysis of 694 posts with 3,468 discussion threads, we identified 12 types of architecture refactoring based on two classification dimensions. Additionally, we categorized architecture problems faced by practitioners and explored their corresponding refactoring solutions. Furthermore, we revealed six potential risks that may result from architecture refactoring. We believe that our study can provide valuable insights for practitioners to perform architecture refactoring effectively. The findings can serve as a foundation for future research and offer practical guidance to improve architecture quality.

In recent years, the development of Solidity smart contracts has been increasing rapidly in popularity. Code cloning is a common coding practice, and many prior studies have revealed that code clones could negatively impact software maintenance and quality. However, there is little work systematically analyzing the nature and impacts of code clones in solidity smart contracts. To bridge this gap, we investigate the prevalence, evolution, and bug-proneness of code clones in solidity smart contracts, and further identify the possible reasons for these clones' occurrences. With our evaluation of 26,294 smart contracts with 97,877 functions, we have found that code clones are highly prevalent in smart contracts. Additionally, on average, 32.01% of clones co-evolve, indicating the need for careful management to avoid consistency issues. Surprisingly, unlike in traditional software development, code clones in smart contracts are rarely involved in bug fixes. Finally, we identify three main factors that affect the occurrences of clones. We believe our study can provide valuable insights for developers to understand and manage code clones in solidity smart contracts.