Finding the same exception in different subsegments should reuse the same cause id

sdk/src/Core/Strategies/DefaultExceptionSerializationStrategy.cs

@@ -154,6 +154,7 @@ public List<ExceptionDescriptor> DescribeException(Exception e, IEnumerable<Subs
             if (existingDescriptor != null)
             {
                 ex.Cause = existingDescriptor.Id != null ? existingDescriptor.Id : existingDescriptor.Cause;
+                ex.Exception = existingDescriptor.Exception; // pass the exception of the cause so that this reference can be found if the same exception is thrown again
                 ex.Id = null;  // setting this to null since, cause is already populated with reference to downstream exception
                 result.Add(ex);
                 return result;

sdk/test/UnitTests/AWSXRayRecorderBuilderTests.cs

@@ -67,8 +67,8 @@ public void Initialize()
             _recorder.Dispose();
             AWSXRayRecorder.Instance.Dispose();
             _recorder = null;
-            
-            
+
+
         }
 
         [TestMethod]
@@ -292,7 +292,7 @@ public void TestExceptionStrategy5() // Test custom exception strategy
             AWSXRayRecorder.Instance.BeginSegment("parent", TraceId);
 
             var segment = AWSXRayRecorder.Instance.TraceContext.GetEntity();
-          
+
             try
             {
                 recorder.BeginSubsegment("child1");
@@ -388,6 +388,60 @@ public void TestExceptionStrategy6() // Setting stack frame size to 0, so no sta
             Assert.AreEqual("AmazonServiceException", segment.Subsegments[0].Subsegments[0].Cause.ExceptionDescriptors[0].Type);
         }
 
+        [TestMethod]
+        public void TestExceptionStrategy7() // Test adding the same exception in different subsegments
+        {
+            List<Type> l = new List<Type>();
+            l.Add(typeof(ArgumentNullException));
+            var recorder = new AWSXRayRecorderBuilder().WithExceptionSerializationStrategy(new DefaultExceptionSerializationStrategy(10, l)).Build(); // set custom stackframe size
+            AWSXRayRecorder.InitializeInstance(recorder: recorder);
+            AWSXRayRecorder.Instance.BeginSegment("parent", TraceId);
+
+            var segment = AWSXRayRecorder.Instance.TraceContext.GetEntity();
+
+            try
+            {
+                recorder.BeginSubsegment("child1");
+                try
+                {
+                    try
+                    {
+                        recorder.BeginSubsegment("child2");
+                        throw new AmazonServiceException();
+                    }
+                    catch (AmazonServiceException e)
+                    {
+                        recorder.AddException(e);
+                        recorder.EndSubsegment();
+                        throw;
+                    }
+                }
+                catch (AmazonServiceException e)
+                {
+                    recorder.AddException(e);
+                    recorder.EndSubsegment();
+                    throw new EntityNotAvailableException("Dummy message", e);
+                }
+            }
+            catch (EntityNotAvailableException e)
+            {
+                recorder.AddException(e);
+                recorder.EndSegment();
+            }
+
+            Assert.AreEqual("Dummy message", segment.Cause.ExceptionDescriptors[0].Message);
+            Assert.AreEqual("EntityNotAvailableException", segment.Cause.ExceptionDescriptors[0].Type);
+            Assert.IsFalse(segment.Cause.ExceptionDescriptors[0].Remote); // default false
+            Assert.AreEqual(segment.Cause.ExceptionDescriptors[0].Cause, segment.Subsegments[0].Cause.ExceptionDescriptors[0].Id);
+            Assert.AreEqual(1, segment.Cause.ExceptionDescriptors.Count);
+
+            Assert.IsNull(segment.Subsegments[0].Cause.ExceptionDescriptors[0].Type);
+            Assert.IsFalse(segment.Subsegments[0].Cause.ExceptionDescriptors[0].Remote); // default false
+
+            Assert.AreEqual("AmazonServiceException", segment.Subsegments[0].Subsegments[0].Cause.ExceptionDescriptors[0].Type);
+            Assert.IsTrue(segment.Subsegments[0].Subsegments[0].Cause.ExceptionDescriptors[0].Remote); // set to true
+        }
+
         [TestMethod]
         [ExpectedException(typeof(ArgumentNullException))]
         public void TestSetNullExceptionSerializationStrategy()
@@ -457,7 +511,7 @@ public void SetDaemonAddress(string daemonAddress)
             }
         }
 
-       public class DummyTraceContext : ITraceContext
+        public class DummyTraceContext : ITraceContext
         {
             public void ClearEntity()
             {