A RepositoryRestMvcConfiguration subclass provided by a user is
problematic in a Spring Boot application as it causes
RepositoryRestMvcConfiguration's bean declarations to be processed
before any auto-configuration runs.
One problem that this causes is that it switches off Boot's Jackson
auto-configuration due to RepositoryRestMvcConfiguration having
already declared multiple ObjectMapper beans. Unlike Boot's
auto-configured ObjectMapper, none of these ObjectMappers are marked
as @Primary. This then leads to wiring failures due to multiple
candidates being available.
To address this problem a new RepositoryRestConfigurer abstract has been
introduced in Spring Data Gosling. Its use is now strongly preferred
over subclassing RepositoryRestMvcConfiguration. Note that our own
RepositoryRestMvcConfiguration subclass remains. It is imported as part
of auto-configuration (avoiding the ordering problems described above),
and provides configuration properties binding for
RepositoryRestConfiguration. However, the Jackson ObjectMapper
configuration has been moved out into a new RepositoryRestConfigurer
implementation.
While SpringBootRepositoryRestMvcConfiguration remains, this commit
makes it package private to discourage users from subclassing it. While
this may break existing applications, it, coupled with the documentation
updates, will hopefully guide them toward using
RepositoryRestConfigurer.
Closes gh-3439
24c63c9b55