Send failures could lock transport into single concurrency mode

[WilliamBZA]

Symptoms

After a dispatch failure arms the external integration's circuit breaker, it may fail to recover, causing the transport to shut down.

Who's affected

All users of NServiceBus.Transport.SqlServer and NServiceBus.Transport.Postgresql.

Root cause

A race condition in the circuit breaker logic could, under the right conditions, result in the circuit breaker becoming armed, but subsequent successful messages could not disarm it unless another failure happened.

[WilliamBZA]

Fixed by 8.1.9 and 7.0.11. Will be released soon.

[SimonCropp]

@WilliamBZA will this also trigger a release of servicecontrol? given it uses the transport assemblies?

[WilliamBZA]

@SimonCropp Yes there will be a release for SC. 6.6.4 already includes the internal fix for SC, transports will be released once Particular/ServiceControl#5025 is completed.

[SimonCropp]

@WilliamBZA thanks

[WilliamBZA]

FYI @SimonCropp ServiceControl has been released with the SQL Transport updated.