fix: Stack trace lost when exception is thrown the when using decorator

libraries/src/AWS.Lambda.Powertools.Common/Aspects/IMethodAspectHandler.cs

@@ -38,11 +38,10 @@ public interface IMethodAspectHandler
     /// <summary>
     ///     Called when [exception].
     /// </summary>
-    /// <typeparam name="T"></typeparam>
     /// <param name="eventArgs">The <see cref="AspectEventArgs" /> instance containing the event data.</param>
     /// <param name="exception">The exception.</param>
     /// <returns>T.</returns>
-    T OnException<T>(AspectEventArgs eventArgs, Exception exception);
+    void OnException(AspectEventArgs eventArgs, Exception exception);
 
     /// <summary>
     ///     Handles the <see cref="E:Exit" /> event.

libraries/src/AWS.Lambda.Powertools.Common/Aspects/MethodAspectAttribute.cs

@@ -64,7 +64,8 @@ protected internal sealed override T WrapSync<T>(Func<object[], T> target, objec
         }
         catch (Exception exception)
         {
-            return AspectHandler.OnException<T>(eventArgs, exception);
+            AspectHandler.OnException(eventArgs, exception);
+            throw;
         }
         finally
         {
@@ -92,7 +93,8 @@ protected internal sealed override async Task<T> WrapAsync<T>(Func<object[], Tas
         }
         catch (Exception exception)
         {
-            return AspectHandler.OnException<T>(eventArgs, exception);
+            AspectHandler.OnException(eventArgs, exception);
+            throw;
         }
         finally
         {

libraries/src/AWS.Lambda.Powertools.Logging/Internal/LoggingAspectHandler.cs

@@ -16,6 +16,7 @@
 using System;
 using System.IO;
 using System.Linq;
+using System.Runtime.ExceptionServices;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using AWS.Lambda.Powertools.Common;
@@ -203,16 +204,16 @@ public void OnSuccess(AspectEventArgs eventArgs, object result)
     /// <summary>
     ///     Called when [exception].
     /// </summary>
-    /// <typeparam name="T"></typeparam>
     /// <param name="eventArgs">
     ///     The <see cref="T:AWS.Lambda.Powertools.Aspects.AspectEventArgs" /> instance containing the
     ///     event data.
     /// </param>
     /// <param name="exception">The exception.</param>
-    /// <returns>T.</returns>
-    public T OnException<T>(AspectEventArgs eventArgs, Exception exception)
+    public void OnException(AspectEventArgs eventArgs, Exception exception)
     {
-        throw exception;
+        // The purpose of ExceptionDispatchInfo.Capture is to capture a potentially mutating exception's StackTrace at a point in time:
+        // https://learn.microsoft.com/en-us/dotnet/standard/exceptions/best-practices-for-exceptions#capture-exceptions-to-rethrow-later
+        ExceptionDispatchInfo.Capture(exception).Throw();
     }
 
     /// <summary>

libraries/src/AWS.Lambda.Powertools.Metrics/Internal/MetricsAspectHandler.cs

@@ -15,6 +15,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Runtime.ExceptionServices;
 using AWS.Lambda.Powertools.Common;
 
 namespace AWS.Lambda.Powertools.Metrics;
@@ -122,14 +123,14 @@ public void OnSuccess(AspectEventArgs eventArgs, object result)
     /// <summary>
     ///     OnException runs when an unhandled exception occurs inside the method marked with the Metrics Attribute
     /// </summary>
-    /// <typeparam name="T">Type of Exception expected</typeparam>
     /// <param name="eventArgs">Aspect Arguments</param>
     /// <param name="exception">Exception thrown by the method marked with Metrics Attribute</param>
-    /// <returns>Type of the Exception expected</returns>
     /// <exception cref="Exception">Generic unhandled exception</exception>
-    public T OnException<T>(AspectEventArgs eventArgs, Exception exception)
+    public void OnException(AspectEventArgs eventArgs, Exception exception)
     {
-        throw exception;
+        // The purpose of ExceptionDispatchInfo.Capture is to capture a potentially mutating exception's StackTrace at a point in time:
+        // https://learn.microsoft.com/en-us/dotnet/standard/exceptions/best-practices-for-exceptions#capture-exceptions-to-rethrow-later
+        ExceptionDispatchInfo.Capture(exception).Throw();
     }
 
     /// <summary>

libraries/src/AWS.Lambda.Powertools.Tracing/Internal/TracingAspectHandler.cs

@@ -14,6 +14,7 @@
  */
 
 using System;
+using System.Runtime.ExceptionServices;
 using System.Text;
 using AWS.Lambda.Powertools.Common;
 
@@ -152,14 +153,12 @@ public void OnSuccess(AspectEventArgs eventArgs, object result)
     /// <summary>
     ///     Called when [exception].
     /// </summary>
-    /// <typeparam name="T"></typeparam>
     /// <param name="eventArgs">
     ///     The <see cref="T:AWS.Lambda.Powertools.Aspects.AspectEventArgs" /> instance containing the
     ///     event data.
     /// </param>
     /// <param name="exception">The exception.</param>
-    /// <returns>T.</returns>
-    public T OnException<T>(AspectEventArgs eventArgs, Exception exception)
+    public void OnException(AspectEventArgs eventArgs, Exception exception)
     {
         if (CaptureError())
         {
@@ -187,7 +186,9 @@ public T OnException<T>(AspectEventArgs eventArgs, Exception exception)
             );
         }
 
-        throw exception;
+        // The purpose of ExceptionDispatchInfo.Capture is to capture a potentially mutating exception's StackTrace at a point in time:
+        // https://learn.microsoft.com/en-us/dotnet/standard/exceptions/best-practices-for-exceptions#capture-exceptions-to-rethrow-later
+        ExceptionDispatchInfo.Capture(exception).Throw();
     }
 
     /// <summary>

libraries/tests/AWS.Lambda.Powertools.Logging.Tests/AWS.Lambda.Powertools.Logging.Tests.csproj

@@ -10,6 +10,7 @@
     <ItemGroup>
         <PackageReference Include="Amazon.Lambda.ApplicationLoadBalancerEvents" Version="2.1.0" />
         <PackageReference Include="Amazon.Lambda.APIGatewayEvents" Version="2.5.0" />
+        <PackageReference Include="Amazon.Lambda.Core" Version="2.1.0" />
         <PackageReference Include="coverlet.collector" Version="3.2.0">
           <PrivateAssets>all</PrivateAssets>
           <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

libraries/tests/AWS.Lambda.Powertools.Logging.Tests/Handlers/ExceptionFunctionHandler.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Globalization;
+using System.Threading.Tasks;
+
+namespace AWS.Lambda.Powertools.Logging.Tests.Handlers;
+
+public class ExceptionFunctionHandler
+{
+    [Logging]
+    public async Task<string> Handle(string input)
+    {
+        ThisThrows();
+
+        await Task.Delay(1);
+
+        return input.ToUpper(CultureInfo.InvariantCulture);
+    }
+
+    private void ThisThrows()
+    {
+        throw new NullReferenceException();
+    }
+}

libraries/tests/AWS.Lambda.Powertools.Logging.Tests/Handlers/ExceptionFunctionHandlerTests.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace AWS.Lambda.Powertools.Logging.Tests.Handlers;
+
+public sealed class ExceptionFunctionHandlerTests
+{
+    [Fact]
+    public async Task Stack_Trace_Included_When_Decorator_Present()
+    {
+        // Arrange
+        var handler = new ExceptionFunctionHandler();
+
+        // Act
+        Task Handle() => handler.Handle("whatever");
+
+        // Assert
+        var tracedException = await Assert.ThrowsAsync<NullReferenceException>(Handle);
+        Assert.StartsWith("at AWS.Lambda.Powertools.Logging.Tests.Handlers.ExceptionFunctionHandler.ThisThrows()", tracedException.StackTrace?.TrimStart());
+
+    }
+}

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/AWS.Lambda.Powertools.Metrics.Tests.csproj

@@ -13,6 +13,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="Amazon.Lambda.Core" Version="2.1.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0-preview-20221221-03" />
         <PackageReference Include="xunit" Version="2.4.2" />
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/Handlers/ExceptionFunctionHandler.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Globalization;
+using System.Threading.Tasks;
+
+namespace AWS.Lambda.Powertools.Metrics.Tests.Handlers;
+
+public class ExceptionFunctionHandler
+{
+    [Metrics(Namespace = "ns", Service = "svc")]
+    public async Task<string> Handle(string input)
+    {
+        ThisThrows();
+
+        await Task.Delay(1);
+
+        return input.ToUpper(CultureInfo.InvariantCulture);
+    }
+
+    private void ThisThrows()
+    {
+        throw new NullReferenceException();
+    }
+}

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/Handlers/ExceptionFunctionHandlerTests.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace AWS.Lambda.Powertools.Metrics.Tests.Handlers;
+
+[Collection("Sequential")]
+public sealed class ExceptionFunctionHandlerTests
+{
+    [Fact]
+    public async Task Stack_Trace_Included_When_Decorator_Present()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var handler = new ExceptionFunctionHandler();
+
+        // Act
+        Task Handle() => handler.Handle("whatever");
+
+        // Assert
+        var tracedException = await Assert.ThrowsAsync<NullReferenceException>(Handle);
+        Assert.StartsWith("at AWS.Lambda.Powertools.Metrics.Tests.Handlers.ExceptionFunctionHandler.ThisThrows()", tracedException.StackTrace?.TrimStart());
+
+    }
+}

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/MetricsTests.cs

@@ -11,6 +11,7 @@ public class MetricsTests
     public void Metrics_Set_Execution_Environment_Context()
     {
         // Arrange
+        Metrics.ResetForTest();
         var assemblyName = "AWS.Lambda.Powertools.Metrics";
         var assemblyVersion = "1.0.0";
 
@@ -32,5 +33,7 @@ public void Metrics_Set_Execution_Environment_Context()
             v.GetEnvironmentVariable(
                 "AWS_EXECUTION_ENV"
             ), Times.Once);
+
+
     }
 }

libraries/tests/AWS.Lambda.Powertools.Tracing.Tests/AWS.Lambda.Powertools.Tracing.Tests.csproj

@@ -13,6 +13,7 @@
     </ItemGroup>
 
     <ItemGroup>
+        <PackageReference Include="Amazon.Lambda.Core" Version="2.1.0" />
         <PackageReference Include="coverlet.collector" Version="3.2.0">
           <PrivateAssets>all</PrivateAssets>
           <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

libraries/tests/AWS.Lambda.Powertools.Tracing.Tests/Handlers/ExceptionFunctionHandler.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Globalization;
+using System.Threading.Tasks;
+
+namespace AWS.Lambda.Powertools.Tracing.Tests.Handlers;
+
+public class ExceptionFunctionHandler
+{
+    [Tracing(CaptureMode = TracingCaptureMode.ResponseAndError)]
+    public async Task<string> Handle(string input)
+    {
+        ThisThrows();
+
+        await Task.Delay(1);
+
+        return input.ToUpper(CultureInfo.InvariantCulture);
+    }
+
+    private void ThisThrows()
+    {
+        throw new NullReferenceException();
+    }
+}

libraries/tests/AWS.Lambda.Powertools.Tracing.Tests/Handlers/ExceptionFunctionHandlerTests.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace AWS.Lambda.Powertools.Tracing.Tests.Handlers;
+
+public sealed class ExceptionFunctionHandlerTests
+{
+    [Fact]
+    public async Task Stack_Trace_Included_When_Decorator_Present()
+    {
+        // Arrange
+        var handler = new ExceptionFunctionHandler();
+
+        // Act
+        Task Handle() => handler.Handle("whatever");
+
+        // Assert
+        var tracedException = await Assert.ThrowsAsync<NullReferenceException>(Handle);
+        Assert.StartsWith("at AWS.Lambda.Powertools.Tracing.Tests.Handlers.ExceptionFunctionHandler.ThisThrows()", tracedException.StackTrace?.TrimStart());
+
+    }
+}