Prior to this commit, the findMergedRepeatableAnnotations() methods in
AnnotatedElementUtils failed to find repeatable annotations declared
on other repeatable annotations (i.e., when one repeatable annotation
type was used as a meta-annotation on a different repeatable annotation
type).
The reason is that
findMergedRepeatableAnnotations(element, annotationType, containerType)
always used RepeatableContainers.of(annotationType, containerType) to
create a RepeatableContainers instance, even if the supplied
containerType was null. Doing so restricts the search to supporting
only repeatable annotations whose container is the supplied
containerType and prevents the search from finding repeatable
annotations declared as meta-annotations on other types of repeatable
annotations.
Note, however, that direct use of the MergedAnnotations API already
supported finding nested repeatable annotations when using
RepeatableContainers.standardRepeatables() or
RepeatableContainers.of(...).and(...).and(...). The latter composes
support for multiple repeatable annotation types and their containers.
This commit addresses the issue for findMergedRepeatableAnnotations()
when the containerType is null or not provided.
However, findMergedRepeatableAnnotations(element, annotationType, containerType)
still suffers from the aforementioned limitation, and the Javadoc has
been updated to make that clear.
Closes gh-20279
828f74f71a