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tyrielvtyrielv
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Add unit tests for deferred telemetry pipe attachment
Cover the buffering, replay, cap, and retry interval logic added in the previous commits. Test seams (CreateDeferredForTesting, TryAttachTestListener, GetRetryInterval) are internal so only the unit test assembly can use them. Tests: - Buffer and replay telemetry messages on attach - Non-telemetry messages are not buffered - Buffer caps at 1000 messages - Second attach attempt returns false - Null/empty gitBinRoot returns false - Retry interval exponential backoff values - Events after attach go directly to listener Assisted-by: Claude Opus 4.6 Signed-off-by: Tyrie Vella <tyrielv@gmail.com>
1 parent e272141 commit 6e409de

2 files changed

Lines changed: 178 additions & 1 deletion

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‎GVFS/GVFS.Common/Tracing/JsonTracer.cs‎

Lines changed: 41 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -91,6 +91,46 @@ public JsonTracer(string providerName, Guid providerActivityId, string activityN
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}
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}
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/// <summary>
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/// Creates a JsonTracer in deferred telemetry mode for testing.
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/// No timer is started — call TryAttachTelemetryPipe manually.
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/// </summary>
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internal static JsonTracer CreateDeferredForTesting(string providerName, string activityName)
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{
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JsonTracer tracer = new JsonTracer(null, Guid.Empty, activityName, EventLevel.Informational, Keywords.Telemetry);
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tracer.deferredProviderName = providerName;
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tracer.deferredMessages = new ConcurrentQueue<TraceEventMessage>();
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return tracer;
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}
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/// <summary>
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/// Attaches the given listener as if TelemetryDaemonEventListener
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/// had been created, replaying buffered messages. For testing only.
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/// </summary>
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internal bool TryAttachTestListener(EventListener listener)
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{
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lock (this.deferredLock)
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{
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if (this.deferredMessages == null)
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{
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return false;
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}
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this.listeners.Add(listener);
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ConcurrentQueue<TraceEventMessage> queue = this.deferredMessages;
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this.deferredMessages = null;
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this.StopDeferredRetryTimer();
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while (queue.TryDequeue(out TraceEventMessage message))
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{
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listener.RecordMessage(message);
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}
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return true;
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}
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}
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private JsonTracer(ConcurrentBag<EventListener> listeners, Guid parentActivityId, string activityName, EventLevel startStopLevel, Keywords startStopKeywords)
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{
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this.listeners = listeners ?? new ConcurrentBag<EventListener>();
@@ -562,7 +602,7 @@ private void OnDeferredRetryTimer(object state)
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}
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}
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private static int GetRetryInterval(int retryCount)
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internal static int GetRetryInterval(int retryCount)
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{
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return retryCount switch
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{

‎GVFS/GVFS.UnitTests/Common/JsonTracerDeferredTests.cs‎

Lines changed: 137 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,137 @@
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using GVFS.Common.Tracing;
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using GVFS.Tests.Should;
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using GVFS.UnitTests.Mock.Common.Tracing;
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using NUnit.Framework;
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namespace GVFS.UnitTests.Common
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{
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[TestFixture]
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public class JsonTracerDeferredTests
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{
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[TestCase]
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public void DeferredMode_BuffersTelemetryMessages()
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{
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using (JsonTracer tracer = JsonTracer.CreateDeferredForTesting("TestProvider", "BufferTest"))
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using (MockListener replayListener = new MockListener(EventLevel.Verbose, Keywords.Telemetry))
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{
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tracer.RelatedEvent(EventLevel.Informational, "Event1", metadata: null, keyword: Keywords.Telemetry);
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tracer.RelatedEvent(EventLevel.Informational, "Event2", metadata: null, keyword: Keywords.Telemetry);
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bool attached = tracer.TryAttachTestListener(replayListener);
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attached.ShouldBeTrue();
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replayListener.EventNamesRead.Count.ShouldEqual(2);
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replayListener.EventNamesRead.ShouldContain(name => name.Equals("Event1"));
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replayListener.EventNamesRead.ShouldContain(name => name.Equals("Event2"));
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}
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}
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[TestCase]
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public void DeferredMode_DoesNotBufferNonTelemetryMessages()
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{
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using (JsonTracer tracer = JsonTracer.CreateDeferredForTesting("TestProvider", "NonTelemetryTest"))
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using (MockListener replayListener = new MockListener(EventLevel.Verbose, Keywords.Any))
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{
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tracer.RelatedEvent(EventLevel.Informational, "TelemetryEvent", metadata: null, keyword: Keywords.Telemetry);
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tracer.RelatedEvent(EventLevel.Informational, "NonTelemetryEvent", metadata: null, keyword: Keywords.Network);
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tracer.RelatedEvent(EventLevel.Informational, "PlainEvent", metadata: null);
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bool attached = tracer.TryAttachTestListener(replayListener);
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attached.ShouldBeTrue();
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// Only the telemetry event should have been buffered and replayed
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replayListener.EventNamesRead.Count.ShouldEqual(1);
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replayListener.EventNamesRead.ShouldContain(name => name.Equals("TelemetryEvent"));
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}
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}
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[TestCase]
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public void DeferredMode_CapsBufferAtMaxMessages()
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{
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using (JsonTracer tracer = JsonTracer.CreateDeferredForTesting("TestProvider", "CapTest"))
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using (MockListener replayListener = new MockListener(EventLevel.Verbose, Keywords.Telemetry))
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{
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// Emit 1050 telemetry events — only 1000 should be buffered
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for (int i = 0; i < 1050; i++)
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{
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tracer.RelatedEvent(EventLevel.Informational, $"Event{i}", metadata: null, keyword: Keywords.Telemetry);
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}
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bool attached = tracer.TryAttachTestListener(replayListener);
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attached.ShouldBeTrue();
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replayListener.EventNamesRead.Count.ShouldEqual(1000);
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replayListener.EventNamesRead[0].ShouldEqual("Event0");
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replayListener.EventNamesRead[999].ShouldEqual("Event999");
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}
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}
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[TestCase]
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public void TryAttachTestListener_ReturnsFalseWhenNotDeferred()
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{
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using (JsonTracer tracer = new JsonTracer("TestProvider", "NotDeferredTest", disableTelemetry: true))
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using (MockListener listener = new MockListener(EventLevel.Verbose, Keywords.Any))
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{
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// Tracer was not created in deferred mode
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bool attached = tracer.TryAttachTestListener(listener);
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attached.ShouldBeFalse();
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}
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}
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[TestCase]
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public void TryAttachTestListener_SecondAttachReturnsFalse()
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{
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using (JsonTracer tracer = JsonTracer.CreateDeferredForTesting("TestProvider", "DoubleAttachTest"))
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using (MockListener listener1 = new MockListener(EventLevel.Verbose, Keywords.Telemetry))
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using (MockListener listener2 = new MockListener(EventLevel.Verbose, Keywords.Telemetry))
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{
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tracer.TryAttachTestListener(listener1).ShouldBeTrue();
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// Second attach should fail — no longer in deferred mode
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tracer.TryAttachTestListener(listener2).ShouldBeFalse();
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}
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}
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[TestCase]
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public void TryAttachTelemetryPipe_ReturnsFalseWithNullGitBinRoot()
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{
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using (JsonTracer tracer = JsonTracer.CreateDeferredForTesting("TestProvider", "NullGitBinTest"))
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{
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bool attached = tracer.TryAttachTelemetryPipe(null);
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attached.ShouldBeFalse();
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attached = tracer.TryAttachTelemetryPipe(string.Empty);
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attached.ShouldBeFalse();
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}
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}
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[TestCase(0, 10_000)]
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[TestCase(1, 30_000)]
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[TestCase(2, 60_000)]
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[TestCase(3, 300_000)]
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[TestCase(4, 300_000)]
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[TestCase(100, 300_000)]
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public void GetRetryInterval_ReturnsExpectedValues(int retryCount, int expectedMs)
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{
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JsonTracer.GetRetryInterval(retryCount).ShouldEqual(expectedMs);
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}
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[TestCase]
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public void DeferredMode_StopsBufferingAfterAttach()
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{
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using (JsonTracer tracer = JsonTracer.CreateDeferredForTesting("TestProvider", "StopBufferTest"))
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using (MockListener listener = new MockListener(EventLevel.Verbose, Keywords.Telemetry))
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{
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tracer.RelatedEvent(EventLevel.Informational, "BeforeAttach", metadata: null, keyword: Keywords.Telemetry);
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tracer.TryAttachTestListener(listener).ShouldBeTrue();
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// Events after attach go directly to listener, not buffered
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tracer.RelatedEvent(EventLevel.Informational, "AfterAttach", metadata: null, keyword: Keywords.Telemetry);
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listener.EventNamesRead.Count.ShouldEqual(2);
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listener.EventNamesRead.ShouldContain(name => name.Equals("BeforeAttach"));
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listener.EventNamesRead.ShouldContain(name => name.Equals("AfterAttach"));
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}
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}
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}
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}

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