After a restart or rebind, a checkout whose HEAD moved since its saved search index now updates that index from the git diff in the warm load lane, instead of queueing for a heavy build slot behind semantic builds. Diffs over 512 paths (renames count twice) still take a build slot and do a full refresh, so large branch switches stay under the shared build limit. Scoring and routing are unchanged; descriptor engine_unwired.
Summary by cubic
A restarted or rebound checkout whose HEAD moved now reloads from its saved search index in the warm load lane over a git diff, instead of queueing behind semantic builds.
Warm refreshes admit at most 512 unique paths from the union of git-diff changes and disk-stale, new, or removed files (renames count twice); larger changes fall back to the existing cold-build permit and full refresh, including same-HEAD disk edits.
Git diffs are read NUL-delimited and scoped with --relative, so quoted names (non-ASCII, tab, quotes, backslashes) count once, same-stat committed edits are still reread, and a search root inside a monorepo ignores changes outside it.
Admission is decided from metadata before any source reads; the stat snapshot is reused for verification and indexing, so admitted files are statted, read, hashed, and verified once, with reads on the bounded warm-worker pool and updates applied on the caller thread.
Cache loading canonicalizes the project root before deriving file keys, and cached keys keep the loading root's spelling, so symlink and Windows verbatim-path, casing, or 8.3 short-name aliases neither hide cached edits or removals nor falsely exhaust the budget.
Boundary, overflow, concurrent-read, and four-held-build tests use hang guards instead of CI throughput deadlines.
Same-size warm-reload fixtures now empty the git index and backdate mtimes so their edits commit deterministically on Windows CI.
Scoring and routing are unchanged; the benchmark descriptor stays engine_unwired.
Confidence Score: 5/5
The PR appears safe to merge; no new actionable issues remain.
Summary
Small search-index refreshes now use the warm-load lane when HEAD moves. Changes above the combined 512-path budget fall back to a full rebuild under a shared build permit.
Saved search indexes refresh changed files without waiting for a build slot.
Cached search files stay visible when a checkout uses a root alias.
Diagram
%%{init: {'theme': 'neutral'}}%%
flowchart TD
A[Load saved search index] --> B{Compatible cache?}
B -->|No| E[Wait for shared build permit]
B -->|Yes| C[Collect Git changes and disk metadata]
C --> D{At most 512 changed paths?}
D -->|Yes| F[Verify and refresh in warm lane]
D -->|No| E
E --> G[Build full index]
F --> H[Save and publish ready index]
G --> H
