Uber's SubmitQueue: A High-Performance Speculative Merge Queue
Uber SubmitQueue: a high-performance speculative merge queue
Uber has open-sourced SubmitQueue, a high-performance speculative merge queue designed to keep your main branch consistently green at scale. It works by speculatively merging and testing pull requests in parallel, catching conflicts and failures before they hit the trunk. The project includes a detailed CI workflow for handling stacked PRs, distinguishing between GitHub-native stacks and hand-rolled chains to ensure proper rebasing and branch cleanup. This tool is ideal for teams that need to maintain a stable main branch while merging many changes quickly.
With the workflow off, merging any PR in a hand-rolled chain leaves the children still carrying their parent's commits — precisely the broken-diff problem this workflow was written to fix.