Placeholder AlarmStateChanged rows are a DebugView snapshot-only concept emitted
by InstanceActor.BuildAlarmStatesSnapshot; they are never a real alarm transition.
Their timestamp may be DateTimeOffset.MinValue (the Protobuf Timestamp lower boundary),
which can throw when packed via Timestamp.FromDateTimeOffset.
Added early-return guard at the top of HandleAlarmStateChanged before any timestamp
pack or channel write. Updated the existing NativeBindingLinkage round-trip test to
use a real (non-placeholder) native alarm; added DropsAlarmStateChanged_WhenIsConfiguredPlaceholder
to assert placeholders are silently dropped (15/15 pass).
Add two additive init-only fields to AlarmStateChanged so the Debug View can
nest live native conditions under their configured source-binding node:
- NativeSourceCanonicalName (binding canonical name, e.g. "Motor1.MotorAlarms")
- IsConfiguredPlaceholder (quiet-binding placeholder flag; default false)
Flow on BOTH cross-process paths:
- Live: proto AlarmStateUpdate fields 22/23 -> StreamRelayActor packs ->
SiteStreamGrpcClient unpacks (regenerated SiteStreamGrpc/Sitestream.cs).
- Snapshot (Newtonsoft): record defaults carry through; no special handling.
NativeAlarmActor.Emit now stamps NativeSourceCanonicalName = _source.CanonicalName.
Additive-only: no existing positional constructor or wire frame changed.
Tests: StreamRelayActorTests round-trips both fields pack->unpack;
NativeAlarmActorTests asserts the emitted event carries the binding canonical name.
Replace ValueFormatter.FormatDisplayValue with AttributeValueCodec.Encode
in StreamRelayActor so List<T> attribute values cross the gRPC wire as a
JSON array (e.g. ["a","b"]) rather than a comma-joined display string.
Scalars and null values are unaffected. Tests cover List→JSON, scalar
string pass-through, and null→empty-string.
- MockSiteStreamGrpcClient.SubscribeCalls and UnsubscribedCorrelationIds
switched from bare List<T> to lock-guarded backing fields with snapshot
accessors, eliminating the actor-thread/test-thread data race (matches
the existing lock(events) pattern for ReceivedEvents)
- AttributeKey and AlarmKey null-guard each component with ?? string.Empty
so a null SourceReference/AlarmName/etc. cannot silently collide with an
empty-string component in the dedup dictionary
- On_Snapshot_Opens_GrpcStream renamed to
On_Snapshot_Does_Not_Open_Additional_GrpcStream; assertion updated to
confirm exactly one subscribe (the PreStart stream-first open) with no
second subscribe after snapshot delivery
- _stopped ordering in InstanceNotFound path moved after CleanupGrpc()
for consistency with DebugStreamTerminated and ReceiveTimeout handlers
Re-architect DebugStreamBridgeActor from snapshot-first to stream-first so no
attribute/alarm event occurring during the snapshot-build + network-transit
window is lost (#26).
Lifecycle change:
- PreStart now opens the gRPC subscription FIRST (alongside sending the
SubscribeDebugViewRequest), so live events start flowing immediately.
- Phase model via a single _snapshotDelivered flag (mutated only on the actor
thread). While buffering (snapshot not yet delivered), AttributeValueChanged/
AlarmStateChanged are appended to an ordered _preSnapshotBuffer instead of
being delivered. After snapshot+flush, the same handlers pass through directly.
- On DebugViewSnapshot: deliver snapshot, then flush the buffer in arrival order
with per-entity dedup, then set _snapshotDelivered=true (pass-through).
Dedup rule (exactly-once):
- Identity: attributes by (InstanceUniqueName, AttributePath, AttributeName);
alarms by (InstanceUniqueName, AlarmName, SourceReference) so native
per-condition alarms are not conflated. Keys joined with a NUL delimiter
(declared as an escaped char constant; no raw NUL in source) so distinct
identities never collide on a space within a name.
- Boundary: a buffered event whose timestamp is <= the snapshot's timestamp for
the same entity is already reflected -> DROP; strictly-newer (>) -> DELIVER;
entity absent from the snapshot -> DELIVER (genuine gap-window event).
Preserved paths:
- M2.11 InstanceNotFound: with stream-first the gRPC stream is already open, so
the not-found path now tears it down (CleanupGrpc) + clears the buffer, does
NOT enter pass-through, delivers the not-found snapshot, and stops cleanly.
- Reconnect (ReconnectGrpcStream -> OpenGrpcStream) does not touch the phase
flag: a mid-session reconnect resumes pass-through; a reconnect during the
buffering phase stays buffering until the snapshot arrives.
- Communication-008 retry/stability/stop/terminate + ReceiveTimeout orphan net
unchanged. Duplicate/late snapshot after delivery is ignored defensively.
Tests: 10 new M2.18 tests (stream-first ordering, gap-window buffering, dedup
drop/deliver for attrs + alarms, ordering, pass-through, InstanceNotFound
teardown, reconnect-during-buffering, reconnect-after-snapshot) + revised the
M2.11 not-found test to assert stream teardown. Full DebugStreamBridgeActor
class green: 23/23.
- Add DebugStreamBridgeActorTests: On_InstanceNotFound_Snapshot_Forwards_To_OnEvent_Does_Not_Open_Stream_And_Terminates — asserts _onEvent receives the not-found snapshot, SubscribeCalls remains empty, and the actor terminates cleanly via Watch/ExpectTerminated.
- Add comment in DebugStreamBridgeActor near Context.Stop(Self) explaining that the subsequent StopDebugStream Tell from DebugStreamService.StopStream produces a benign expected dead-letter.
- Reword not-found toast in DebugView.razor to "Instance not found on the selected site — check the deployment target." (accurate when the instance may be deployed to a different site).
Joseph Doherty