micronaut-validator validates Optional.empty() as null when using @NotNull

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Task List

[X] Steps to reproduce provided
[X] Stacktrace (if present) provided
[X] Example that reproduces the problem uploaded to Github
[X] Full description of the issue provided (see below)

Steps to Reproduce

Annotate a method attribute as @NotNull
put Optional.empty() in it
get a unexpected ConstraintViolationException

Just run the tests in the example project to reproduce.

Expected Behaviour

Optional.empty() is something different than null and should not cause a ConstraintViolationException exception.

Actual Behaviour

Optional.empty() causes a ConstraintViolationException: greet.name: the greeting name is required javax.validation.ConstraintViolationException: greet.name: the greeting name is required at io.micronaut.validation.ValidatingInterceptor.intercept(ValidatingInterceptor.java:143) at io.micronaut.aop.chain.MethodInterceptorChain.proceed(MethodInterceptorChain.java:69) at de.flexguse.micronaut.demo.service.ExampleServiceImplTest.should greet #name(ExampleServiceImplTest.groovy:21)

Environment Information

Operating System: Windows 10 Pro 64 Bit / WSL
Micronaut Version: 1.3.0.RC1
JDK Version: 11

Example Application

https://github.com/flexguse/micronaut-optional-validation-demo

micronaut-projects / micronaut-core