Reject attempt to use @MockitoSpyBean with a scoped proxy #35722

Stubbing method calls on a @MockitoSpyBean in conjunction with ScopedProxyMode.TARGET_CLASS results in java.lang.IllegalStateException: Failed to unwrap proxied object.

Steps to reproduce:

1. Write a Spring bean that uses @Scope(proxyMode = ScopedProxyMode.TARGET_CLASS).
2. In an integration test, make it a spy bean.
3. Mock a call to the spy bean.
4. Run the test.

I think the issue could be in org.springframework.test.context.bean.override.mockito.SpringMockResolver.getUltimateTargetObject. It invokes the method org.springframework.aop.framework.Advised#getTargetSource() on the spy bean and is (indirectly) called by org.mockito.internal.stubbing.StubberImpl#when(T mock), which means when(T mock) is not finished when getTargetSource() is called.

Please find the attached reproducer which has a full setup. Slightly more detailed information can be found in the contained README.md.

spy-beans.zip