[Grails 5] Unclear how to enable codecs for Java 8 date/time class marshalling

[MichaelJRussell]

I've reviewed the documentation at https://gorm.grails.org/latest/mongodb/manual/, I don't see how to take advantage of the codecs in groovy.org.grails.datastore.bson.codecs. My assumption was that just adding the MongoDb plugin to my application would automatically enable marshalling/unmarshalling of Java 8 types such as LocalDate and ZonedDateTime, but instead they're serialized as String, and when retrieved I receive an exception. Details follow.

Steps I took:

• Create a new Grails (v5.1.7) app: grails create-app test-mongo --profile rest-api
• Add the Gorm MongoDb plugin to build.config: implementation 'org.grails.plugins:mongodb:7.3.0'
• Create a trivial Domain and associated Controller with save & list endpoints), with LocalDate and ZonedDateTime props
• Add MongoDb connection settings to local dev config in application.yml

POST to /foo successful, but serializes LocalDate and ZonedDateTime as String. On GET, receive the following error:

Failed to convert property value of type 'java.lang.String' to required type 'java.time.LocalDate' for property 'dob'; nested exception is java.lang.IllegalStateException: Cannot convert value of type 'java.lang.String' to required type 'java.time.LocalDate' for property 'dob': no matching editors or conversion strategy found

I also tried adding this: implementation 'org.grails:grails-datastore-gorm-mongodb:7.3.0', but same result.

Example repo: https://github.com/MichaelJRussell/mongo-test

• build.gradle: https://github.com/MichaelJRussell/mongo-test/blob/main/build.gradle
• Domain: https://github.com/MichaelJRussell/mongo-test/blob/main/grails-app/domain/Foo.groovy