ReadStoreSnapshotAsync's snapshot is read off the actor thread and consumed only
when its piped message lands. Row 101 guarded the DEFINITIONS half of that race;
the CONFIG half was left to machinery whose reach is time-limited, and both legs
of the instance reconcile sweep were reachable through it:
- Row-72 leg: a read dispatched before a deploy's persist, landing after the
deploy completed AND after the pipeline released ownership, carries the
revision the deploy replaced. TryRestartStaleInstance then "repairs" the
instance BACKWARD, re-deploying the snapshot's own superseded ConfigJson.
InstanceIsOwnedByADeployPipeline covers only in-flight deploys, and the
per-revision claim has never seen the old revision, so nothing stopped it.
- Row-78 leg: a read dispatched before a delete/disable commits still shows an
enabled row while the actor is already stopped, so StartStoredInstance
resurrects it — and delete clears _sweepAttemptedRevisions, freeing the claim.
Both verified real by neutralising the freshness check and re-running the new
tests (the fail-before site event literally reads "running revision rev-2 is
stale, applying stored revision rev-1"; the deleted instance came back).
_definitionsWriteGeneration becomes _storeWriteGeneration, covering both tables
(the snapshot is one consistent read and is discarded whole, so one counter is
the right shape); DefinitionsGenerationAtRead -> StoreGenerationAtRead on both
internal records. The generation is now bumped at BOTH ends of every mutation —
when the off-thread write is dispatched and when its completion message lands —
because the config paths advance actor state before the write, so an
initiation-only bump would let an in-window read look fresh. Disable, delete and
the init-failure rollback have no actor-thread completion message of their own,
so a minimal StoreWriteCompleted self-message carries the bump for them.
CDC-replicated writes, snapshot resyncs, restored files and
SiteReconciliationActor's fetch deliberately do NOT bump: discovering exactly
those is the sweep's reason to exist.
A stale sweep result is now dropped WHOLE (no overlay apply, no start, no
restart). A stale boot load cannot be dropped — startup must finish — so it
re-dispatches LoadDeployedConfigs(); a fifth consecutive superseded read is
applied anyway with a Warning, and a late one arriving after the boot completed
is dropped rather than looping against the S5 retry timer.
Tests: three fail-before regressions (backward restart, resurrection, boot
re-read) plus two guard twins pinning that the legitimate row-72 restart and
row-78 start still fire on a current-generation snapshot. The row-101
definitions tests keep passing; FreshEmptySweepSnapshot's hardcoded generation
moves 1 -> 2 now that one artifact apply bumps at both ends.
Docs: Component-SiteRuntime.md's stale-snapshot paragraph now describes the
whole snapshot (both halves, both consumers, the boot re-dispatch, the
CDC-no-bump rule), the components mirror follows, and the arbitration memo gains
§11 extending §10 to the config half.
Joseph Doherty
f02e116688