This commit polishes SPR-16022 fix in order to handle correctly
the case when primary and default constructors are the same when
a secondary constructor is defined.
Issue: SPR-16289
Autowiring implicitely Kotlin primary constructors
when there are secondary constructors has side effects
on ConstructorResolver. It seems reasonable to
require explicit @Autowired annotation in such case.
With this commit, implicit autowiring of Kotlin
primary constructors is only performed when there
is a primary constructor defined alone or with
a default constructor (define explicitly or
generated via the kotlin-noarg compiler plugin
or via optional constructor parameters with default
values).
Issue: SPR-16022
Includes unified detection of Kotlin's optional parameters in MethodParameter.isOptional(), reduces BeanUtils.findPrimaryConstructor to Kotlin semantics (for reuse in AutowiredAnnotationBeanPostProcessor), and finally introduces a common KotlinDetector delegate with an isKotlinType(Class) check.
Issue: SPR-15877
Issue: SPR-16020
This commit introduces the following changes.
1) It adds a new Spring @NonNull annotation which allows to apply
@NonNullApi semantic on a specific element, like @Nullable does.
Combined with @Nullable, it allows partial null-safety support when
package granularity is too broad.
2) @Nullable and @NonNull can apply to ElementType.TYPE_USE in order
to be used on generic type arguments (SPR-15942).
3) Annotations does not apply to ElementType.TYPE_PARAMETER anymore
since it is not supported yet (applicability for such use case is
controversial and need to be discussed).
4) @NonNullApi does not apply to ElementType.FIELD anymore since in a
lot of use cases (private, protected) it is not part for the public API
+ its usage should remain opt-in. A dedicated @NonNullFields annotation
has been added in order to set fields default to non-nullable.
5) Updated Javadoc and reference documentation.
Issue: SPR-15756
This commit adds support for autowired constructor parameters
on Kotlin classes with optional parameters. If some constructor
parameters are not available, optional parameter default values
will be used instead. Both explicit @Autowired annotated constructor
and implicit single constructor automatically autowired are supported.
Issue: SPR-15847
Juergen Hoeller
igor-suhorukov
Stephane Nicoll
Kamil Szymanski
sdeleuze
Christoph Dreis