fix: recompute package snapshot when missing from cache #95
2026-06-17
fix: recompute package snapshot when missing from cache
The install-deps step precomputes pkgs_to_build.rds, r_minor_sensitive_pkgs.rds and s3_cache.rds into /mnt/cache, but that cache volume is per-agent. A build job scheduled on a fresh agent (or racing install-deps) finds the snapshot absent and fails at readRDS. Guard the reads in build-all.R: when any snapshot file is missing, source packages-to-build.R and save the derived files (atomic temp+rename so a concurrent job never reads a half-written rds). The first job on an agent repopulates the shared cache for subsequent jobs; jobs that also miss redo the work.