False positive NSB0033 for Handle methods implementing a derived IHandleMessages

[SimonCropp]

Symptoms

The compiler reports a false positive NSB0033 diagnostic for Handle methods implementing implementing an interface derived from IHandleMessages<T>.

Who's affected

Users of NServiceBus 10.2.0 using an intermediate interface to identify handlers rather than using IHandleMessages<T> directly.`

Root cause

The use case of an intermediate marker interface was not considered in the analyzer design.

Original bug report

Fix NSB0033 false positive for Handle methods implementing a derived IHandleMessages interface The mixed-style check treated any Handle(message, context, ...) method with more than two parameters as convention-based, even when that method is the implementation of an interface member. This produced a false positive for handlers that implement a custom interface deriving from IHandleMessages which exposes an extended Handle signature (e.g. an extra CancellationToken) backed by a default interface method that forwards to the two-parameter IHandleMessages.Handle.
IsValidConventionBasedHandleMethod now classifies a Handle method that implements any interface member as interface-based rather than convention-based, regardless of parameter count.

[danielmarbach]

@SimonCropp thanks for the PR with the fix and the reproduction. This is tremendously helpful! I have pushed a few changes and will wait for the others to also review it.

[SimonCropp]

thanks peoples

[DavidBoike]

@SimonCropp 10.2.1 now released