Rendering Huge Pull Requests in the GitHub Copilot App
The GitHub Blog
GitHub rebuilt the pull request diff view in the GitHub Copilot app to stay fast when displaying a very large diff with review threads. The biggest pull request they tested had 2,200 files, over 1,000,000 changed lines, and more than 400 inline review comments. The UI now uses separate geometry for deterministic code vs dynamically measured comment blocks, plus scroll-anchoring and a batched measurement scheduler so resizing and comment rendering adjust without major scroll jumps.
Why it matters
GitHub rebuilt the Copilot app's pull request view to keep a diff with 2,200 files, more than one million changed lines, and over 400 inline comments responsive. It separates fixed code geometry from lazily measured comment blocks, then uses instrumentation and automated stress loops to catch scroll jumps, leaks, and jank.