Ensure validators accessible as beans from usingContext (#337)

* Ensure validators accessible as beans from usingContext

The usingContext method of DefaultValidatoryFactory is updated to check
for an existing non-null ValidatorConfiguration that is itself an
instance of ValidatorContext (which will always be the case when
created via DI).

This allows custom validation constraints to be located in the
BeanContext when validation is invoked by a Jakarta validation
implementation.

* Code improvement for Sonar

validation/src/main/java/io/micronaut/validation/validator/DefaultValidatorFactory.java

@@ -75,9 +75,13 @@ public jakarta.validation.Validator getValidator() {
 
     @Override
     public ValidatorContext usingContext() {
-        DefaultValidatorConfiguration newValidatorConfiguration = new DefaultValidatorConfiguration();
-        newValidatorConfiguration.setBeanIntrospector(configuration.getBeanIntrospector());
-        return newValidatorConfiguration;
+        if (configuration instanceof ValidatorContext validatorContext) {
+            return validatorContext;
+        } else {
+            DefaultValidatorConfiguration newValidatorConfiguration = new DefaultValidatorConfiguration();
+            newValidatorConfiguration.setBeanIntrospector(configuration.getBeanIntrospector());
+            return newValidatorConfiguration;
+        }
     }
 
     @Override

validation/src/test/groovy/io/micronaut/validation/validator/constraints/custom/CustomConstraintsSpec.groovy

@@ -4,6 +4,7 @@ import io.micronaut.context.ApplicationContext
 import io.micronaut.core.annotation.Introspected
 import io.micronaut.validation.validator.Validator
 import jakarta.validation.Valid
+import jakarta.validation.ValidatorFactory
 import spock.lang.AutoCleanup
 import spock.lang.Shared
 import spock.lang.Specification
@@ -15,6 +16,8 @@ class CustomConstraintsSpec extends Specification {
     ApplicationContext applicationContext = ApplicationContext.run()
     @Shared
     Validator validator = applicationContext.getBean(Validator)
+    @Shared
+    ValidatorFactory validatorFactory = applicationContext.getBean(ValidatorFactory)
 
     void "test validation where pojo with inner custom constraint fails"() {
         given:
@@ -194,6 +197,19 @@ class CustomConstraintsSpec extends Specification {
         then:
         result == "AB"
     }
+
+    void "test custom validator bean can be invoked when using jakarta validation ValidatorFactory.usingContext"() {
+        given:
+        TestInvalid testInvalid = new TestInvalid(invalidInner: new TestInvalid.InvalidInner())
+        Validator contextualValidator = validatorFactory.usingContext().getValidator() as Validator
+
+        when:
+        def violations = contextualValidator.validate(testInvalid)
+
+        then:
+        violations.size() == 1
+        violations[0].message == "invalid"
+    }
 }
 
 @Introspected