This commit updates BeanUtils class in order to add Kotlin optional
parameters with default values support to the immutable data classes
support introduced by SPR-15199.
Issue: SPR-15673
This commit ensure that null-safety is consistent between
getters and setters in order to be able to provide beans
with properties with a common type when type safety is
taken in account like with Kotlin.
It also add a few missing property level @Nullable
annotations.
Issue: SPR-15792
Currently ResourceEncoder and ResourceRegionEncoder use DataBufferUtils
to read resource with an AsynchronousFileChannel if it is a file or
otherwise fallback on getting the channel from the resource.
The same is now required in other places where a Resource needs to be
read and is also generally useful.
Issue: SPR-15773
This commit changes the write methods to return `Flux<DataBuffer>`
instead of `Mono<Void>`, giving access to the original buffers,
so that they can decided whether the buffers need to be closed or not.
Issue: SPR-15726
This commit adds an overloaded write method to `DataBufferUtils`. There
are three parameter variants: `OutputStream`, `WritableByteChannel`, and
`AsynchronousFileChannel`.
Issue: SPR-15726
This commits extends nullability declarations to the field level, formalizing the interaction between methods and their underlying fields and therefore avoiding any nullability mismatch.
Issue: SPR-15720
This commit improves the capacity calculation for the DefaultDataBuffer,
so that the capacity typically doubles instead of improving by the
minimal required amount.
Issue: SPR-15647
This commit also removes nullability from two common spots: ResolvableType.getType() and TargetSource.getTarget(), both of which are never effectively null with any regular implementation. For such scenarios, a non-null empty type/target is the cleaner contract.
Issue: SPR-15540
Update AnnotationUtils to restore support for `null` arguments in
certain methods. Some existing upstream projects were relying on this
behavior.
Issue: SPR-15642
Beyond just formally declaring the current behavior, this revision actually enforces non-null behavior in selected signatures now, not tolerating null values anymore when not explicitly documented. It also changes some utility methods with historic null-in/null-out tolerance towards enforced non-null return values, making them a proper citizen in non-null assignments.
Some issues are left as to-do: in particular a thorough revision of spring-test, and a few tests with unclear failures (ignored as "TODO: NULLABLE") to be sorted out in a follow-up commit.
Issue: SPR-15540
Defining nullability of some API like EnvironmentCapable
or ConditionContext causes issues in Spring Boot because
in the context where they are used, it is known for sure
they will return non-null values even if their API can in
other context return null values.
It is better in this case for both Java and Kotlin to
not define at all the nullabity of such API.
In practice, this is achieved by removing the package level
@NonNullApi annotation and adding it only on the
relevant classes.
Issue: SPR-15540
This commit makes Spring @Nullable annotation leveraging
JSR 305 @TypeQualifierNickname + @Nonnull(when= When.MAYBE)
instead of directly using @javax.annotation.Nullable which
seems not designed to be used as a meta-annotation.
It also removes @TypeQualifierDefault since the purpose of
this annotation when applied at method level is to only
change return value nullability, not parameters one.
Issue: SPR-15540
This commit introduces 2 new @Nullable and @NonNullApi
annotations that leverage JSR 305 (dormant but available via
Findbugs jsr305 dependency and already used by libraries
like OkHttp) meta-annotations to specify explicitly
null-safety of Spring Framework parameters and return values.
In order to avoid adding too much annotations, the
default is set at package level with @NonNullApi and
@Nullable annotations are added when needed at parameter or
return value level. These annotations are intended to be used
on Spring Framework itself but also by other Spring projects.
@Nullable annotations have been introduced based on Javadoc
and search of patterns like "return null;". It is expected that
nullability of Spring Framework API will be polished with
complementary commits.
In practice, this will make the whole Spring Framework API
null-safe for Kotlin projects (when KT-10942 will be fixed)
since Kotlin will be able to leverage these annotations to
know if a parameter or a return value is nullable or not. But
this is also useful for Java developers as well since IntelliJ
IDEA, for example, also understands these annotations to
generate warnings when unsafe nullable usages are detected.
Issue: SPR-15540
