Streamline the extracting logic to make the message ID handling explicit

src/NServiceBus.Transport.SQS.Tests/InputQueuePumpTests.cs

@@ -429,8 +429,6 @@ await SetupInitializedPump(onMessage: (ctx, ct) =>
 
         [Theory]
         [TestCase(TransportHeaders.Headers, "{}")]
-        // [TestCase(TransportHeaders.MessageTypeFullName)] special case that is forwarded due to historic reason
-        [TestCase(TransportHeaders.S3BodyKey)]
         [TestCase(TransportHeaders.DelaySeconds)]
         [TestCase(TransportHeaders.TimeToBeReceived)]
         public async Task Excluded_transport_headers_are_not_propagate_to_transport_message_headers(string headerKey, string headerValue = "custom-header-value")

src/NServiceBus.Transport.SQS/Extensions/TransportMessageExtensions.cs

@@ -3,14 +3,38 @@ namespace NServiceBus.Transport.SQS.Extensions
 {
     using System;
     using System.Buffers;
+    using System.Collections.Generic;
     using System.IO;
+    using System.Linq;
     using System.Text;
     using System.Threading;
     using System.Threading.Tasks;
     using Amazon.S3.Model;
+    using Amazon.SQS.Model;
 
     static class TransportMessageExtensions
     {
+        public static void CopyMessageAttributes(this TransportMessage transportMessage, Dictionary<string, MessageAttributeValue>? receiveMessageAttributes)
+        {
+            foreach (var messageAttribute in receiveMessageAttributes ??
+                                             Enumerable.Empty<KeyValuePair<string, MessageAttributeValue>>())
+            {
+                // The message ID requires complicated special handling and in the majority of cases
+                // the NServiceBus message ID when present on the headers might take precedence
+                if (messageAttribute.Key == Headers.MessageId)
+                {
+                    continue;
+                }
+
+                transportMessage.Headers[messageAttribute.Key] = messageAttribute.Value.StringValue;
+            }
+
+            // These headers are not needed in the transport message and would only blow up the message size.
+            _ = transportMessage.Headers.Remove(TransportHeaders.Headers);
+            _ = transportMessage.Headers.Remove(TransportHeaders.DelaySeconds);
+            _ = transportMessage.Headers.Remove(TransportHeaders.TimeToBeReceived);
+        }
+
         public static async ValueTask<(ReadOnlyMemory<byte> MessageBody, byte[]? MessageBodyBuffer)> RetrieveBody(this TransportMessage transportMessage, string messageId, S3Settings s3Settings, ArrayPool<byte> arrayPool,
             CancellationToken cancellationToken = default)
         {

src/NServiceBus.Transport.SQS/InputQueuePump.cs

@@ -298,7 +298,7 @@ internal async Task ProcessMessage(Message receivedMessage, CancellationToken ca
 
                 try
                 {
-                    transportMessage = ExtractTransportMessage(receivedMessage, messageId);
+                    transportMessage = ExtractTransportMessage(receivedMessage, nativeMessageId);
                     messageId = transportMessage.Headers[Headers.MessageId];
                     (messageBody, messageBodyBuffer) = await transportMessage.RetrieveBody(messageId, s3Settings, arrayPool, cancellationToken).ConfigureAwait(false);
                 }
@@ -354,42 +354,34 @@ public static TransportMessage ExtractTransportMessage(Message receivedMessage,
             TransportMessage transportMessage;
             if (receivedMessage.MessageAttributes.TryGetValue(TransportHeaders.Headers, out var headersAttribute))
             {
+                var headers = JsonSerializer.Deserialize<Dictionary<string, string>>(headersAttribute.StringValue) ?? [];
                 transportMessage = new TransportMessage
                 {
-                    Headers = JsonSerializer.Deserialize<Dictionary<string, string>>(headersAttribute.StringValue) ?? [],
+                    Headers = headers,
                     Body = receivedMessage.Body
                 };
-                if (receivedMessage.MessageAttributes.TryGetValue(TransportHeaders.S3BodyKey, out var s3BodyKey))
-                {
-                    transportMessage.Headers[TransportHeaders.S3BodyKey] = s3BodyKey.StringValue;
-                    transportMessage.S3BodyKey = s3BodyKey.StringValue;
-                }
+                transportMessage.CopyMessageAttributes(receivedMessage.MessageAttributes);
+
+                // It is possible that the transport message already had a message ID and that one
+                // takes precedence
+                transportMessage.Headers.TryAdd(Headers.MessageId, messageIdOverride);
+                transportMessage.S3BodyKey = transportMessage.Headers.GetValueOrDefault(TransportHeaders.S3BodyKey);
             }
             else
             {
                 // When the MessageTypeFullName attribute is available, we're assuming native integration
                 if (receivedMessage.MessageAttributes.TryGetValue(TransportHeaders.MessageTypeFullName, out var enclosedMessageType))
                 {
-                    var headers = new Dictionary<string, string>
-                    {
-                                { Headers.MessageId, messageIdOverride },
-                                { Headers.EnclosedMessageTypes, enclosedMessageType.StringValue },
-                                {
-                                    TransportHeaders.MessageTypeFullName, enclosedMessageType.StringValue
-                                } // we're copying over the value of the native message attribute into the headers, converting this into a nsb message
-                            };
-
-                    if (receivedMessage.MessageAttributes.TryGetValue(TransportHeaders.S3BodyKey, out var s3BodyKey))
-                    {
-                        headers.Add(TransportHeaders.S3BodyKey, s3BodyKey.StringValue);
-                    }
-
                     transportMessage = new TransportMessage
                     {
-                        Headers = headers,
-                        S3BodyKey = s3BodyKey?.StringValue,
+                        Headers = [],
                         Body = receivedMessage.Body
                     };
+                    transportMessage.CopyMessageAttributes(receivedMessage.MessageAttributes);
+
+                    transportMessage.Headers[Headers.MessageId] = messageIdOverride;
+                    transportMessage.Headers[Headers.EnclosedMessageTypes] = enclosedMessageType.StringValue;
+                    transportMessage.S3BodyKey = transportMessage.Headers.GetValueOrDefault(TransportHeaders.S3BodyKey);
                 }
                 else
                 {
@@ -405,12 +397,17 @@ public static TransportMessage ExtractTransportMessage(Message receivedMessage,
                             transportMessage = new TransportMessage
                             {
                                 Body = receivedMessage.Body,
-                                Headers = new Dictionary<string, string>
-                                {
-                                    // HINT: Message Id is a required field for InnerProcessMessage
-                                    [Headers.MessageId] = receivedMessage.MessageId,
-                                }
+                                Headers = []
                             };
+                            transportMessage.CopyMessageAttributes(receivedMessage.MessageAttributes);
+                            // For native integration scenarios the native message id should be used
+                            transportMessage.Headers[Headers.MessageId] = receivedMessage.MessageId;
+                        }
+                        else
+                        {
+                            // It is possible that the transport message already had a message ID and that one
+                            // takes precedence
+                            transportMessage.Headers.TryAdd(Headers.MessageId, messageIdOverride);
                         }
                     }
                     catch (Exception ex)
@@ -422,36 +419,18 @@ public static TransportMessage ExtractTransportMessage(Message receivedMessage,
                         transportMessage = new TransportMessage
                         {
                             Body = receivedMessage.Body,
-                            Headers = new Dictionary<string, string>
-                            {
-                                // HINT: Message Id is a required field for InnerProcessMessage
-                                [Headers.MessageId] = receivedMessage.MessageId,
-                            }
+                            Headers = []
                         };
+                        transportMessage.CopyMessageAttributes(receivedMessage.MessageAttributes);
+                        // For native integration scenarios the native message id should be used
+                        transportMessage.Headers[Headers.MessageId] = receivedMessage.MessageId;
                     }
                 }
             }
-            // HINT: Message Id is the only required header
-            transportMessage.Headers.TryAdd(Headers.MessageId, messageIdOverride);
-            AddCustomNativeHeadersToNServiceBusHeaders(receivedMessage, transportMessage);
 
             return transportMessage;
         }
 
-        static void AddCustomNativeHeadersToNServiceBusHeaders(Message receivedMessage, TransportMessage transportMessage)
-        {
-            foreach (var receivedMessageMessageAttribute in receivedMessage.MessageAttributes)
-            {
-                // The code doesn't allow overriding the message ID at this point because
-                // message id has its own complex set of rules handled earlier in the process 
-                if (TransportHeaders.NativeMessageAttributesNotCopiedToNServiceBusHeaders.Contains(receivedMessageMessageAttribute.Key) || receivedMessageMessageAttribute.Key == Headers.MessageId)
-                {
-                    continue;
-                }
-                transportMessage.Headers[receivedMessageMessageAttribute.Key] = receivedMessageMessageAttribute.Value?.StringValue ?? string.Empty;
-            }
-        }
-
         static bool CouldBeNativeMessage(TransportMessage msg)
         {
             if (msg.Headers == null)

src/NServiceBus.Transport.SQS/TransportHeaders.cs

@@ -1,8 +1,5 @@
 namespace NServiceBus.Transport.SQS
 {
-    using System.Collections.Frozen;
-    using System.Collections.Generic;
-
     static class TransportHeaders
     {
         const string Prefix = "NServiceBus.AmazonSQS.";
@@ -11,11 +8,5 @@ static class TransportHeaders
         public const string Headers = Prefix + nameof(Headers);
         public const string S3BodyKey = "S3BodyKey";
         public const string MessageTypeFullName = "MessageTypeFullName";
-
-        // The following set represents the list of native message attributes that will
-        // not be copied to NServiceBus headers. When adding a new header to this class
-        // consider if that needs to be propagated to NServiceBus headers, if not, add it
-        // to this frozen set.
-        public static readonly FrozenSet<string> NativeMessageAttributesNotCopiedToNServiceBusHeaders = new HashSet<string>([TimeToBeReceived, DelaySeconds, Headers, S3BodyKey]).ToFrozenSet();
     }
 }