From d6d9c6012c42f38906f72e07e7dd57cfc49da7a1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 21 Nov 2025 15:09:19 +0000
Subject: [PATCH 1/3] Initial plan


From c07795c54436a418ee00ab4b4645aa9f3e8b0276 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 21 Nov 2025 15:26:38 +0000
Subject: [PATCH 2/3] Fix flaky UnreliableL2Tests.WriteFailureInvisible test by
 waiting for logs

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>
---
 .../LogCollector.cs                           | 33 +++++++++++++++++++
 .../UnreliableL2Tests.cs                      |  4 ++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs b/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs
index bdb5ff981c0..1b350135ee7 100644
--- a/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs
+++ b/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs
@@ -31,6 +31,39 @@ public void WriteTo(ITestOutputHelper log)
         }
     }
 
+    public async Task WaitForLogsAsync(int[] expectedErrorIds, TimeSpan timeout)
+    {
+        var deadline = DateTime.UtcNow + timeout;
+        while (DateTime.UtcNow < deadline)
+        {
+            lock (_items)
+            {
+                if (_items.Count >= expectedErrorIds.Length)
+                {
+                    // Check if we have the expected logs
+                    bool match = true;
+                    for (int i = 0; i < expectedErrorIds.Length; i++)
+                    {
+                        if (_items[i].eventId.Id != expectedErrorIds[i])
+                        {
+                            match = false;
+                            break;
+                        }
+                    }
+
+                    if (match)
+                    {
+                        return; // Success
+                    }
+                }
+            }
+
+            await Task.Delay(10);
+        }
+
+        // Timeout reached, will fail in AssertErrors
+    }
+
     public void AssertErrors(int[] errorIds)
     {
         lock (_items)
diff --git a/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/UnreliableL2Tests.cs b/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/UnreliableL2Tests.cs
index f6232357651..bba5020f58b 100644
--- a/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/UnreliableL2Tests.cs
+++ b/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/UnreliableL2Tests.cs
@@ -43,7 +43,9 @@ public async Task WriteFailureInvisible(BreakType writeBreak, params int[] error
             }
 
             await l2.LastWrite; // allows out-of-band write to complete
-            await Task.Delay(150); // even then: thread jitter can cause problems
+
+            // Wait for logs to be written (with timeout to avoid hanging on failure)
+            await log.WaitForLogsAsync(errorIds, TimeSpan.FromSeconds(5));
 
             log.WriteTo(testLog);
             log.AssertErrors(errorIds);

From bf465a74e57282bbfb3850f4d418e06c6d4af0b7 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 21 Nov 2025 15:30:59 +0000
Subject: [PATCH 3/3] Improve WaitForLogsAsync to match AssertErrors exact
 matching logic

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>
---
 .../LogCollector.cs                                   | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs b/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs
index 1b350135ee7..553fe1f1cd4 100644
--- a/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs
+++ b/test/Libraries/Microsoft.Extensions.Caching.Hybrid.Tests/LogCollector.cs
@@ -38,9 +38,9 @@ public async Task WaitForLogsAsync(int[] expectedErrorIds, TimeSpan timeout)
         {
             lock (_items)
             {
-                if (_items.Count >= expectedErrorIds.Length)
+                // Check for exact match to avoid race conditions with AssertErrors
+                if (_items.Count == expectedErrorIds.Length)
                 {
-                    // Check if we have the expected logs
                     bool match = true;
                     for (int i = 0; i < expectedErrorIds.Length; i++)
                     {
@@ -56,6 +56,13 @@ public async Task WaitForLogsAsync(int[] expectedErrorIds, TimeSpan timeout)
                         return; // Success
                     }
                 }
+
+                // If we have more logs than expected, something unexpected happened
+                // Stop waiting to let AssertErrors report the mismatch
+                if (_items.Count > expectedErrorIds.Length)
+                {
+                    return;
+                }
             }
 
             await Task.Delay(10);