Since Spring Framework 5.2, @RestControllerAdvice registered with
MockMvc when using MockMvcBuilders.standaloneSetup() has no longer been
properly supported if annotation attributes were declared in the
@RestControllerAdvice annotation. Prior to 5.2, this was not an issue.
The cause for this regression is two-fold.
1. Commit 50c257794f refactored
DefaultListableBeanFactory so that findAnnotationOnBean() supports
merged annotations; however, that commit did not refactor
StaticListableBeanFactory#findAnnotationOnBean() to support merged
annotations.
2. Commit 978adbdae7 refactored
ControllerAdviceBean so that a merged @ControllerAdvice annotation
is only looked up via ApplicationContext#findAnnotationOnBean().
The latter relies on the fact that findAnnotationOnBean() supports
merged annotations (e.g., @RestControllerAdvice as a merged instance of
@ControllerAdvice). Behind the scenes, MockMvcBuilders.standaloneSetup()
creates a StubWebApplicationContext which internally uses a
StubBeanFactory which extends StaticListableBeanFactory. Consequently,
since the implementation of findAnnotationOnBean() in
StaticListableBeanFactory was not updated to support merged annotations
like it was in DefaultListableBeanFactory, we only see this regression
with the standalone MockMvc support and not with MockMvc support for an
existing WebApplicationContext or with standard Spring applications
using an ApplicationContext that uses DefaultListableBeanFactory.
This commit fixes this regression by supporting merged annotations in
StaticListableBeanFactory#findAnnotationOnBean() as well.
Closes gh-25520
96da1ff9ea