Phase 3 Task 6. In FetchAndCache mode Bootstrap() branches to BootstrapFromCache(),
which restores served state from the LocalDb pointer (GetCurrentUnkeyedAsync → set
_currentRevision → ApplyCachedArtifact from the cached bytes) with NO central-SQL read.
Distinct from the Direct-mode TryBootFromCache fallback: reading the cache is NORMAL
operation here so _isRunningFromCache stays false (the node can still fetch new
deploys). An empty OR unreadable cache lands Steady-with-no-revision (the first dispatch
fetches), never Stale — Stale means 'central SQL down, retry it', and FetchAndCache has
no config SQL read to recover. TryRecoverFromStale gains a defensive FetchAndCache guard
(it is unreachable in that mode, since the retry-db timer only starts in Stale).
Proven with a ThrowingDbFactory in every test: reaching Steady + applying a dispatch
proves the boot never touched central SQL. Sabotaging the mode branch (fall through to
the SQL read) reddens all three — test A flips RunningFromCache; B/C enter Stale, which
ignores the dispatch.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty