@NewSpan on interface doesn't start new span

[joellp]

Expected Behavior

When I add a @NewSpan annotation on a method of an interface, then I will expect the implementation class to start a new span if that method is called.

Actual Behaviour

The implementation class method does not start a new span when called. It does work if I place the annotation on the method of the implentation class directly.

Steps To Reproduce

1. Create an interface (Interface A) with a method annotated with @NewSpan.
2. Create a class (Class A) and implement the interface. Annotate the class with @singleton.
3. Create another class (Class B) with a method which is annotated with @NewSpan. Annotate the class with @singleton.
4. Start the application and let it inject Interface A and Class B.
5. Call the methods.
6. The call to Interface A does not start a new span. The call to Class B does start a new span.
7. Downgrade micronaut-tracing-zipkin and micronaut-tracing-core to 4.1.1. Now both calls create new spans.

Environment Information

• Windows 10
• Java 17

Example Application

https://github.com/joellp/micronaut-tracing-issue

Version

3.7.3