Prior to this commit, Spring Boot had an `HttpMessageConverters` class
that allowed, to configure message converter instances for MVC server
applications and traditional Spring HTTP clients.
As of Spring Framework 7.0, Framework ships its own
`HttpMessageConverters` class, aligning with the existing codecs
configuration on the WebFlux side. As a result, a few methods taking
`List<HttpMessageConverter>` as arguments were deprecated in favor of
the new arrangement.
This commit adapts to the Framework changes by deprecating Boot's
`HttpMessageConverters` in favor of Framework's. This splits the client
and server configuration as they are meant to be managed separately.
Applications can still contribute `HttpMessageConverters` (Boot's
variant) beans but the type itself is now deprecated.
Instead, applications should now contribute
`ClientHttpMessageConvertersCustomizer` and
`ServerHttpMessageConvertersCustomizer` beans to customize message
converters.
Closes gh-46411
This commit removes the "kotlin-serialization" option from the
`spring.http.converters.preferred-json-mapper` and configures the kotlin
serialization http message converter ahead of the preferred JSON
converter.
This effectively makes Kotlin Serialization a converter that is
considered first for JSON support, and then Jackson/Jsonb/Gson is
considered as fallback.
Closes gh-47178
Moritz Halbritter
Brian Clozel
Phillip Webb
Dmitry Sulman
Andy Wilkinson
Stéphane Nicoll