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
Refactor `PropertyMapper` so that it no longer calls adapter or
predicate methods by default when the source value is `null`. This
effectively makes all default calls the same as using
`alwaysWhenNotNull` in the previous generation of the code.
For the limited times when you do need to deal with `null` values, the
new `always()` method can be used.
For example,
map.from(source::method).to(destination::method);
Will not call `destination.method(...)` if `source.method()` returns
`null`.
Where as:
map.from(source::method).always().to(destination::method);
Will call `destination.method(null)` if `source.method()` returns
`null`.
This update provides clearer semantics for the API and allows for better
JSpecify nullability annotations. It has also simplified much of our
existing property mapper code.
Closes gh-47024
Co-authored-by: Moritz Halbritter <moritz.halbritter@broadcom.com>