Task: Fix sccache cache bloat causing slow/cold builds
This page documents a task in the Engineering hygiene story. It captures the goal, current status, acceptance, and any notes or results.
Goal
Fix the GitHub Actions cache bloat that was forcing CI builds to start cold from sccache.
Status
| Field | Value |
|---|---|
| State | DONE |
| Parent story | Engineering hygiene |
| Now | Completed 2026-03-24. |
| Waiting on | None. |
| Next | None. |
| Last touched | 2026-03-24 |
Acceptance
- GitHub cache size dropped back below the 10 GB repo limit (was at 11.5 GB).
- Per-PR sccache saves rationalised.
- sccache limit increased to avoid within-build LRU eviction across 1,362 source files.
- Cross-PR cache sharing avoids Qt + sccache duplication.
Plan
Captured during execution; cleared into the parent story on close.
Notes
CI was taking 2+ hours for trivial single-file changes; the cache bloat was the root cause.
Result
CI builds back to expected times.