AI 中文总结
本研究针对GitHub分支家族开展大规模实证研究，开发监控平台挖掘分支提交，发现同步悖论等关键结果，揭示分支开发同步的核心问题与原因。
AI 中文摘要
基于分支的开发模式支持软件的并行演化，但未同步的贡献会造成持续的分叉：安全补丁、漏洞修复和质量改进往往无法在分支家族间传播，导致下游用户面临已知漏洞或缺陷，且错失了改进家族内其他仓库的大量机会。我们开展了首个针对分支同步的大规模实证研究，分析了包含3820个活跃维护分支的热门GitHub分支家族，并开发了一个监控平台，用于挖掘有价值的提交并推动其快速合并。研究发现了同步悖论：尽管90%的提交的拉取请求（PR）被合并，但仅6.92%的分支提交会出现在PR中，导致大量分支开发在家族间永久未同步。同步延迟普遍存在且结构不均，其中分支传播占端到端提交生命周期延迟的72.9%。与普遍假设相反，PR拒绝很少由技术错误导致；相反，65%的拒绝源于被替代的贡献、流程违规或维护者的政策决定。
英文摘要
Fork-based development enables parallel evolution of software, but unsynchronized contributions create persistent divergence: security patches, bug fixes, and quality improvements often fail to propagate across fork families, leaving downstream users exposed to known vulnerabilities or bugs and missing massive opportunities to improve the other repositories in the family. We present the first large-scale empirical study of fork synchronization, analyzing popular GitHub fork families with 3,820 actively maintained forks, and developed a monitoring platform to mine the valuable commits and promote their swift merging. Our findings reveal a synchronization paradox: while 90% of submitted pull requests are merged, only 6.92% of fork commits ever appear in PRs, leaving massive fork development permanently unsynchronized across the families. Synchronization delay is pervasive and structurally uneven where fork propagation accounts for 72.9% of end-to-end commit lifecycle delay. Contrary to common assumptions, PR rejection is rarely caused by technical incorrectness; instead, 65% of rejections stem from superseded contributions, process violations, or maintainer policy decisions.
Comments24 pages, ISSTA 2026
