No active Transaction was found for ID

Describe the bug

When performing transactional processing (using TransactionScope and send-via feature) of messages concurrently, using multiple message senders, the System.InvalidOperationException exception is thrown.

Exception or Stack Trace

System.InvalidOperationException: No active Transaction was found for ID 'txn:9e879b829a0e446d97d6ac7625862833:9_G5'. The Transaction may have timed out or attempted to span multiple top-level entities such as Queue or Topic. The server Transaction timeout is: 00:02:00. Reference:fbcf536a-d67a-4a0f-8fb7-7532b8360f78, TrackingId:44c4b18d00000014000024ca5c5832b5_G5_B7, SystemTracker:SOMSYSTEMNAME:Queue:SOMEQUEUENAME, Timestamp:2019-02-04T12:40:21
   at Microsoft.Azure.ServiceBus.Core.MessageSender.OnSendAsync(IList`1 messageList)
   at Microsoft.Azure.ServiceBus.RetryPolicy.RunOperation(Func`1 operation, TimeSpan operationTimeout)
   at Microsoft.Azure.ServiceBus.RetryPolicy.RunOperation(Func`1 operation, TimeSpan operationTimeout)
   at Microsoft.Azure.ServiceBus.Core.MessageSender.SendAsync(IList`1 messageList)
   at NServiceBus.TransportReceiveToPhysicalMessageProcessingConnector.Invoke(ITransportReceiveContext context, Func`2 next)
   at NServiceBus.MainPipelineExecutor.Invoke(MessageContext messageContext)
   at NServiceBus.Transport.AzureServiceBus.MessagePump.ProcessMessage(Task`1 receiveTask)

To Reproduce

Repro code is located in https://github.com/SeanFeldman/TransactionIssueRepro, TransactionIssueRepro.sln

• Sender project is seeding the receiver’s queue with messages
• Receiver project is logging message processing.
• For each processed message, ten outgoing messages are emitted

Code Snippet

See the previous section

Expected behavior

There should be no exceptions.

Screenshots

N/A

Setup (please complete the following information):

• OS: Windows 10 Pro 1903
• IDE : VS 2019 16.1.3
• Azure Service Bus 3.4.0 / netcoreapp2.2

Additional context

When concurrency is set to one and a single outgoing MessageSender is used, this exception is not thrown. Whenever concurrency is higher than one, the exception is thrown.

Originally reported by NServiceBus customers using Azure Service Bus transport here. My investigation led to the native repro w/o NServiceBus code in it.

All NServiceBus customers on ASB transport with transactions enabled are affected 🐼

[SeanFeldman]

@jfggdl I’ve re-run a test and it looks like the fix is in place 🎉 Thank you and the team on my and my customers’ behalf.

[nemakam]

@SeanFeldman , the bug is being worked on. The repro code is doing its job just fine! (y)