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fix(core): resolve Medium code-review finding (Core-006)

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BuildAddressSpaceAsync now checks _disposed (throws ObjectDisposedException)
and tears down the previous alarm forwarder + clears the sink registry
before re-walking, so a Galaxy-redeploy rebuild does not leak the old
forwarder and double-deliver alarm transitions.  Three regression tests
added: double-build does not double-fire, sink count is correct after
rebuild, and post-dispose call throws.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Joseph Doherty
2026-05-22 08:24:08 -04:00
parent debe163f4d
commit 6cec98caef
2 changed files with 70 additions and 2 deletions
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17
src/Core/ZB.MOM.WW.OtOpcUa.Core/OpcUa/GenericDriverNodeManager.cs
View File

@@ -36,12 +36,25 @@ public class GenericDriverNodeManager(IDriver driver) : IDisposable
/// Populates the address space by streaming nodes from the driver into the supplied builder,
/// wraps the builder so alarm-condition sinks are captured, subscribes to the driver's
/// alarm event stream, and routes each transition to the matching sink by <c>SourceNodeId</c>.
/// Driver exceptions are isolated per decision #12 — the driver's subtree is marked Faulted,
/// but other drivers remain available.
/// If called a second time (e.g. Galaxy redeploy via <c>IRediscoverable.OnRediscoveryNeeded</c>)
/// the previous alarm subscription is torn down and the sink registry is cleared before
/// re-walking, preventing double delivery of alarm transitions.
/// Exception isolation (marking the driver's subtree Faulted) is the caller's responsibility —
/// exceptions from <see cref="ITagDiscovery.DiscoverAsync"/> propagate to the caller.
/// </summary>
public async Task BuildAddressSpaceAsync(IAddressSpaceBuilder builder, CancellationToken ct)
{
ArgumentNullException.ThrowIfNull(builder);
ObjectDisposedException.ThrowIf(_disposed, this);
// Tear down any previous alarm subscription before re-walking so a second call (e.g. on
// Galaxy redeploy) does not leave the old forwarder subscribed and double-fire events.
if (_alarmForwarder is not null && Driver is IAlarmSource existingSource)
{
existingSource.OnAlarmEvent -= _alarmForwarder;
_alarmForwarder = null;
}
_alarmSinks.Clear();
if (Driver is not ITagDiscovery discovery)
throw new NotSupportedException($"Driver '{Driver.DriverInstanceId}' does not implement ITagDiscovery.");

55
tests/Core/ZB.MOM.WW.OtOpcUa.Core.Tests/GenericDriverNodeManagerTests.cs
View File

@@ -88,6 +88,61 @@ public sealed class GenericDriverNodeManagerTests
builder.Alarms["Tank.HiHi"].Received.Count.ShouldBe(0);
}
/// <summary>
/// Core-006 regression: a second call to BuildAddressSpaceAsync (e.g. on Galaxy redeploy)
/// must unsubscribe the old alarm forwarder and clear the sink registry before re-walking,
/// so alarm transitions are not delivered twice.
/// </summary>
[Fact]
public async Task Second_BuildAddressSpaceAsync_Does_Not_Double_Fire_Alarms()
{
var driver = new FakeDriver();
var builder1 = new RecordingBuilder();
var builder2 = new RecordingBuilder();
using var nm = new GenericDriverNodeManager(driver);
await nm.BuildAddressSpaceAsync(builder1, CancellationToken.None);
await nm.BuildAddressSpaceAsync(builder2, CancellationToken.None); // redeploy
driver.RaiseAlarm(new AlarmEventArgs(
new FakeHandle("s1"), "Tank.HiHi", "c", "t", "m", AlarmSeverity.High, DateTime.UtcNow));
// Only the second builder's sink should have received the event.
builder2.Alarms["Tank.HiHi"].Received.Count.ShouldBe(1,
"second BuildAddressSpaceAsync must replace the subscription — not add to it");
// The first builder's sink should NOT have received it (old forwarder was detached).
builder1.Alarms.TryGetValue("Tank.HiHi", out var oldSink);
(oldSink?.Received.Count ?? 0).ShouldBe(0,
"the original alarm forwarder must be unsubscribed on the second build");
}
[Fact]
public async Task Second_BuildAddressSpaceAsync_Clears_Old_Sink_Registry()
{
var driver = new FakeDriver();
using var nm = new GenericDriverNodeManager(driver);
await nm.BuildAddressSpaceAsync(new RecordingBuilder(), CancellationToken.None);
var countAfterFirst = nm.TrackedAlarmSources.Count;
await nm.BuildAddressSpaceAsync(new RecordingBuilder(), CancellationToken.None);
var countAfterSecond = nm.TrackedAlarmSources.Count;
countAfterFirst.ShouldBe(2, "FakeDriver registers 2 alarm sources");
countAfterSecond.ShouldBe(2, "second build must re-register exactly the same sources, not accumulate");
}
[Fact]
public async Task BuildAddressSpaceAsync_After_Dispose_Throws_ObjectDisposedException()
{
var driver = new FakeDriver();
var nm = new GenericDriverNodeManager(driver);
nm.Dispose();
await Should.ThrowAsync<ObjectDisposedException>(() =>
nm.BuildAddressSpaceAsync(new RecordingBuilder(), CancellationToken.None));
}
// --- test doubles ---
private sealed class FakeDriver : IDriver, ITagDiscovery, IAlarmSource