From 596055e217fa03f22688bfe1e23161b9ab3a2054 Mon Sep 17 00:00:00 2001
From: Robert Karp <rkarp@ecovadisazure.onmicrosoft.com>
Date: Tue, 9 Jun 2026 08:17:56 +0200
Subject: [PATCH] fix(#446605, #442484): broaden shutdown TaskCanceledException
 guard to cover CancellationToken.None
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The previous guard checked oce.CancellationToken.IsCancellationRequested, but the Azure
ServiceBus SDK raises ProcessErrorAsync with a TaskCanceledException whose CancellationToken
is CancellationToken.None during processor shutdown — so IsCancellationRequested is always
false and the guard never fired. Widening to any OperationCanceledException is safe because
genuine transport errors are ServiceBusException, not OperationCanceledException.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 docs/CHANGELOG.md                             |  4 +++
 .../Management/Wrappers/ReceiverWrapper.cs    |  2 +-
 .../ReceiverWrapperTests.cs                   | 34 ++++++++++++++++---
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 6f7624e..d4df942 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 5.7.3
+- Fixed
+  - Corrected the shutdown `OperationCanceledException` guard introduced in 5.7.2. The previous guard checked `oce.CancellationToken.IsCancellationRequested`, which was always `false` because the Azure ServiceBus SDK raises `ProcessErrorAsync` with `CancellationToken.None` during processor shutdown. The guard now matches any `OperationCanceledException`, which is safe since genuine transport errors surface as `ServiceBusException`.
+
 ## 5.7.2
 - Fixed
   - Suppressed spurious `OperationCanceledException` / `TaskCanceledException` APM error entries during pod graceful shutdown. When the Service Bus receive loop is cancelled with a requested cancellation token, the exception is now logged at `Warning` level instead of `Error`.
diff --git a/src/Ev.ServiceBus/Management/Wrappers/ReceiverWrapper.cs b/src/Ev.ServiceBus/Management/Wrappers/ReceiverWrapper.cs
index 58e6fc3..abc180c 100644
--- a/src/Ev.ServiceBus/Management/Wrappers/ReceiverWrapper.cs
+++ b/src/Ev.ServiceBus/Management/Wrappers/ReceiverWrapper.cs
@@ -132,7 +132,7 @@ private void TrySetReceptionRegistrationOnContext(MessageContext context, IServi
     /// <returns></returns>
     protected async Task OnExceptionOccured(ProcessErrorEventArgs exceptionEvent)
     {
-        if (exceptionEvent.Exception is OperationCanceledException oce && oce.CancellationToken.IsCancellationRequested)
+        if (exceptionEvent.Exception is OperationCanceledException)
         {
             _messageProcessingLogger.LogWarning(
                 "[Ev.ServiceBus] Receive loop cancelled for {ClientType} '{ResourceId}' during shutdown.",
diff --git a/tests/Ev.ServiceBus.UnitTests/ReceiverWrapperTests.cs b/tests/Ev.ServiceBus.UnitTests/ReceiverWrapperTests.cs
index d6086b2..b735f34 100644
--- a/tests/Ev.ServiceBus.UnitTests/ReceiverWrapperTests.cs
+++ b/tests/Ev.ServiceBus.UnitTests/ReceiverWrapperTests.cs
@@ -31,20 +31,44 @@ private static TestableReceiverWrapper CreateWrapper(ILogger<LoggingExtensions.M
     }
 
     [Fact]
-    public async Task OnExceptionOccured_WithCancelledToken_DoesNotLogError()
+    public async Task OnExceptionOccured_WithOperationCanceledException_DoesNotLogError()
     {
         var mockLogger = new Mock<ILogger<LoggingExtensions.MessageProcessing>>();
         var wrapper = CreateWrapper(mockLogger.Object);
 
-        using var cts = new CancellationTokenSource();
-        cts.Cancel();
+        // Azure SDK raises ProcessErrorAsync with CancellationToken.None during shutdown —
+        // the token on the exception is not the shutdown token, so IsCancellationRequested is false.
+        var args = new ProcessErrorEventArgs(
+            new OperationCanceledException("shutdown", CancellationToken.None),
+            ServiceBusErrorSource.Receive,
+            "test-namespace",
+            "test-queue",
+            CancellationToken.None);
+
+        await wrapper.InvokeOnExceptionOccuredAsync(args);
+
+        mockLogger.Verify(
+            x => x.Log(
+                LogLevel.Error,
+                It.IsAny<EventId>(),
+                It.Is<It.IsAnyType>((v, t) => true),
+                It.IsAny<Exception?>(),
+                It.Is<Func<It.IsAnyType, Exception?, string>>((v, t) => true)),
+            Times.Never());
+    }
+
+    [Fact]
+    public async Task OnExceptionOccured_WithTaskCanceledException_DoesNotLogError()
+    {
+        var mockLogger = new Mock<ILogger<LoggingExtensions.MessageProcessing>>();
+        var wrapper = CreateWrapper(mockLogger.Object);
 
         var args = new ProcessErrorEventArgs(
-            new OperationCanceledException("shutdown", cts.Token),
+            new TaskCanceledException(),
             ServiceBusErrorSource.Receive,
             "test-namespace",
             "test-queue",
-            cts.Token);
+            CancellationToken.None);
 
         await wrapper.InvokeOnExceptionOccuredAsync(args);