How the GitHub Copilot app renders enormous pull requests
The GitHub Copilot app rebuilt its pull-request view to render huge PRs smoothly, including one with 2,200 files, more than one million changed lines, and over 400 inline comments. It separates document height into deterministic code geometry and dynamic-block geometry: code line heights are calculated precisely in advance, while dynamic blocks such as comments are anchored by stable keys to a file, line, and side, measured lazily, and adjusted only slightly to avoid scroll jumps.
