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 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
Bean-derived null values may still get passed into bean properties and injection points but only if those are declared as non-required. Note that getBean will never return null; a manual bean.equals(null) / "null".equals(bean.toString()) check identifies expected null values now. This will only ever happen with custom FactoryBeans or factory methods returning null - and since all common cases are handled by autowiring or bean property values in bean definitions, there should be no need to ever manually check for such a null value received from getBean.
Issue: SPR-15829
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
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
* getBeanDefinitionNames defensively returns a copy of the bean definition names array.
* copyConfigurationFrom provides an independent AutowireCandidateResolver instance and copies a ConversionService and dependency comparator configuration as well.
* findAutowireCandidates only considers a self reference fallback for direct dependency declarations, not as a collection element.
Issue: SPR-14897
Issue: SPR-14921
Issue: SPR-14965
Improve RootBeanDefinition to specify an AnnotatedElement that holds
qualifier information. When such element is present, any qualifier that
it defines will be used to find a matching candidate.
Issue: SPR-14725
sdeleuze