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Log4Net guard AppenderAttachedImpl integration against NullReferenceException. #8489

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Log4Net guard AppenderAttachedImpl integration against NullReferenceException. #8489

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180e96c
Fix exception
NachoEchevarria Apr 21, 2026
6034d5d
Log. Nits
NachoEchevarria Apr 21, 2026
b1b28de
loggingEvent cannot be null
NachoEchevarria Apr 22, 2026
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1 change: 0 additions & 1 deletion tracer/missing-nullability-files.csv
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Original file line number Diff line number Diff line change
Expand Up @@ -585,7 +585,6 @@ src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/Log4Net/DirectSubmissi
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/Log4Net/DirectSubmission/ILoggingEventLegacyDuck.cs
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/Log4Net/DirectSubmission/LevelDuck.cs
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/Log4Net/DirectSubmission/LevelDuckExtensions.cs
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/Log4Net/LogsInjection/AppenderAttachedImplIntegration.cs
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/Log4Net/LogsInjection/ILoggingEvent.cs
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/NLog/DirectSubmission/NLogConstants.cs
src/Datadog.Trace/ClrProfiler/AutoInstrumentation/Logging/NLog/LogsInjection/DiagnosticContextHelper.cs
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30 changes: 26 additions & 4 deletions ...iler/AutoInstrumentation/Logging/Log4Net/LogsInjection/AppenderAttachedImplIntegration.cs
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Expand Up @@ -3,10 +3,13 @@
// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
// </copyright>

#nullable enable

using System;
using System.ComponentModel;
using Datadog.Trace.ClrProfiler.AutoInstrumentation.Logging;
using Datadog.Trace.ClrProfiler.CallTarget;
using Datadog.Trace.Logging;

namespace Datadog.Trace.ClrProfiler.AutoInstrumentation.Log4Net
{
Expand All @@ -26,6 +29,9 @@ namespace Datadog.Trace.ClrProfiler.AutoInstrumentation.Log4Net
[EditorBrowsable(EditorBrowsableState.Never)]
public sealed class AppenderAttachedImplIntegration
{
private static readonly IDatadogLogger Log = DatadogLogging.GetLoggerFor(typeof(AppenderAttachedImplIntegration));
private static bool _loggedNullSettings;

/// <summary>
/// OnMethodBegin callback
/// </summary>
Expand All @@ -44,9 +50,25 @@ internal static CallTargetState OnMethodBegin<TTarget, TLoggingEvent>(TTarget in

var tracer = Tracer.Instance;

var mutableSettings = tracer.CurrentTraceSettings.Settings;
var mutableSettings = tracer.CurrentTraceSettings?.Settings;

@bouwkast bouwkast Apr 22, 2026

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I wonder if this is the case if we'd need to guard this elsewhere for other instrumentations, if so something that we can do later

if (mutableSettings is null)
{
if (!_loggedNullSettings)
{
_loggedNullSettings = true;
Log.Debug("log4net logs-injection skipped: CurrentTraceSettings was null.");

@bouwkast bouwkast Apr 22, 2026

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Unsure how valuable this is, if the theory here is correct there will only be an occasional missed injection

@bouwkast bouwkast Apr 22, 2026

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(at least as I understand it)

}

return CallTargetState.GetDefault();
}

if (!mutableSettings.LogsInjectionEnabled)
{
return CallTargetState.GetDefault();
}

var properties = loggingEvent.Properties;
if (mutableSettings.LogsInjectionEnabled && properties != null && !properties.Contains(CorrelationIdentifier.ServiceKey))
if (properties is not null && !properties.Contains(CorrelationIdentifier.ServiceKey))
{
properties[CorrelationIdentifier.ServiceKey] = mutableSettings.DefaultServiceName;
properties[CorrelationIdentifier.VersionKey] = mutableSettings.ServiceVersion ?? string.Empty;
Expand All @@ -60,7 +82,7 @@ internal static CallTargetState OnMethodBegin<TTarget, TLoggingEvent>(TTarget in
}
}

return new CallTargetState(scope: null, state: null);
return CallTargetState.GetDefault();
}

/// <summary>
Expand All @@ -73,7 +95,7 @@ internal static CallTargetState OnMethodBegin<TTarget, TLoggingEvent>(TTarget in
/// <param name="exception">Exception instance in case the original code threw an exception.</param>
/// <param name="state">Calltarget state value</param>
/// <returns>A response value, in an async scenario will be T of Task of T</returns>
internal static CallTargetReturn<TReturn> OnMethodEnd<TTarget, TReturn>(TTarget instance, TReturn returnValue, Exception exception, in CallTargetState state)
internal static CallTargetReturn<TReturn> OnMethodEnd<TTarget, TReturn>(TTarget instance, TReturn returnValue, Exception? exception, in CallTargetState state)
{
return new CallTargetReturn<TReturn>(returnValue);
}
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