Mirrors the Medium wave's DebugView P6-6 fix (_sessionLock + _disposed,
publish-then-recheck-disposal under one lock) for the two TTL-bounded/
unbounded lesser instances the Medium wave deferred:
- TransportImport.razor.cs: TryLoadAsync awaits IBundleImporter.LoadAsync and
used to publish the result into _session unconditionally. A circuit torn
down mid-await left Dispose() with nothing to release (session still null),
so the freshly-opened server-side BundleSession stayed registered, stranding
one of MaxConcurrentImportSessions (register row 43) for the full session
TTL. Now publishes and re-checks disposal atomically under _sessionLock, so
exactly one side (TryLoadAsync or Dispose) abandons the session.
- Topology.razor: OnInitializedAsync awaits LoadDataAsync before calling
StartLiveUpdatesTimer. A circuit torn down mid-await left Dispose() with no
timer to stop yet, so the timer StartLiveUpdatesTimer creates once the await
resumes was never disposed — it ticked against a torn-down component every
15s until process restart. StartLiveUpdatesTimer/StopLiveUpdatesTimer/
Dispose now create/replace/take the timer atomically under _timerLock
together with a _disposed check, so a late-arriving (re)start refuses to
create a timer once disposed.
Tests (bUnit, both proven to fail against the unfixed code):
- TransportImportSessionDisposeRaceTests: dispose-during-load abandons the
just-opened session immediately; dispose-after-successful-load abandons
exactly once.
- TopologyLiveUpdatesTimerDisposeRaceTests: a late StartLiveUpdatesTimer call
after Dispose leaves no live timer; Dispose stops the timer exactly once
(idempotent double-dispose); OnLiveUpdatesToggled(off) + Dispose leaves no
live timer. All assert on deterministic field/call-order state, no sleeps.
Register row 103 stays open for integration to close per the plan's shared
constraints (register edits happen at integration only).
Joseph Doherty