OpenAI's work on Git for large repositories

OpenAI's Git development team published a series of patches improving performance and reliability for large repositories. Taylor Blau's bitmap selection change reduced MIDX bitmap write time from 984.73 seconds to 200.06 seconds, while a fix by Ted Nyman eliminated a six-hour static-analysis timeout caused by a reused loop index. Additional patches added parallel checkout diagnostics and a cache file to speed up git status.

- From - Ted Nyman - Date - 24 Jul 2026 - Patches - 1 A reused loop index made Coccinelle's static analysis run for hours and hit CI's six-hour limit. Declare separate loop indexes so static analysis can finish normally. Branch deletion behaves exactly as before; each loop variable now stays within the loop that uses it. −6 h static-analysis timeout +5 lines isolated loop indexes - From - Taylor Blau - Date - 14 Jul 2026 - Patches - 5 Bitmap selection undervalued merge commits that expose large amounts of repository history. Choose bitmap commits based on the history they make reachable rather than path length alone. The measured build fell from 984.73 seconds to 200.06 seconds while both runs selected the same 578 bitmaps. −984.73 s MIDX bitmap write +200.06 s MIDX bitmap write - From - Taylor Blau - Date - 20 Jul 2026 - Patches - 2 Parallel checkout reported collisions but not how work was distributed among workers. Record each worker's item count, bytes, failures, elapsed time, and slowest item when Trace2 is enabled. These counters show whether a long checkout comes from uneven work or one unusually slow file. - From - Taylor Blau - Date - 29 Jul 2026 Files can change between a bulk content check and the final filesystem-monitor query. Keep the scanned file descriptors and metadata available until the final filesystem-monitor check. Accept the results only after confirming that no concurrent worktree change invalidated the scan. - From - Taylor Blau - Date - 21 Jul 2026 Document an optional .csts file that records a known-clean git status --porcelain=v2 result. On a main APFS worktree, reuse the result only after checking the index, HEAD, configuration, attributes, ignore rules, and filesystem-monitor history. Missing, stale, or malformed cache files always fall back to ordinary status.