ApplyAndAck advanced _currentRevision and recorded NodeDeploymentState=Applied
immediately after ReconcileDrivers, which returns null when the artifact could
not be read. So a node that applied NOTHING reported success, claimed a
revision whose configuration it never applied, and — because
HandleDispatchFromSteady short-circuits on a revision match — could never be
healed by re-dispatching that revision. Only a later, different revision
recovered it.
Now a null blob fails the apply: the revision is left where it was,
NodeDeploymentState records Failed with the reason, and the coordinator gets a
Failed ACK. Leaving the revision alone is what makes the retry actually land
instead of being waved through.
This is about telling the truth, not about tearing anything down — the node
keeps serving its last-known-good address space, drivers and subscriptions
throughout (#485).
Tests, RED-first (both verified failing with "should be Failed but was
Applied"): the ACK/revision assertion, plus the one that matters — after a
failed apply, re-dispatching the SAME revision now genuinely applies. Its
recovered artifact adds a second driver precisely so a short-circuited ACK
(which has no side effects) cannot satisfy it.
Four existing tests changed, and both changes are deliberate:
- DriverHostActorTests.SeedDeployment never set ArtifactBlob at all. Its three
consumers are about the apply/ACK/state machine, not the artifact, and now
need a genuine apply — so the helper seeds a well-formed artifact declaring
no drivers. That is what the composer emits for an empty configuration, and
is precisely what "bytes we could not read" is NOT.
- EmptyArtifact_IsNotCached asserted "the apply still succeeds — an empty
artifact is a legitimate no-op deployment". That premise is the bug. Flipped
to Failed; the test's actual subject (nothing is cached) is untouched and now
holds for two independent reasons.
Closes#486
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty
ef41a43102