Studying Pull Request Merges: A Case Study of Shopify's Active Merchant

Pull-based development has become a popular choice for developing distributed projects, such as those hosted on GitHub. In this model, contributions are pulled from forked repositories, modified, and then later merged back into the main repository. In this work, we report on two empirical studies that investigate pull request (PR) merges of Active Merchant, a commercial project developed by Shopify Inc. In the first study, we apply data mining techniques on the project's GitHub repository to explore the nature of merges, and we conduct a manual inspection of pull requests; we also investigate what factors contribute to PR merge time and outcome. In the second study, we perform a qualitative analysis of the results of a survey of developers who contributed to Active Merchant. The study addresses the topic of PR review quality and developers' perception of it. The results provide insights into how these developers perform pull request merges, and what factors they find contribute to how they review and merge pull requests.