Issue with persisting embedded null values

[kfujita-cohere]

Our team has faced issues with persisting null values on embedded fields. I did some debugging and found something that was a bit confusing.

The encodeEmbeddedUpdate method is only passing through the v param to encodeUpdate: https://github.com/grails/gorm-mongodb/blob/8.1.x/grails-datastore-gorm-mongodb/src/main/groovy/org/grails/datastore/mapping/mongo/engine/codecs/PersistentEntityCodec.groovy#L439

This results in embedded being set to false: https://github.com/grails/gorm-mongodb/blob/8.1.x/grails-datastore-gorm-mongodb/src/main/groovy/org/grails/datastore/mapping/mongo/engine/codecs/PersistentEntityCodec.groovy#L199

It then skips adding the null field to the unsets array, causing no change to the field in the database: https://github.com/grails/gorm-mongodb/blob/8.1.x/grails-datastore-gorm-mongodb/src/main/groovy/org/grails/datastore/mapping/mongo/engine/codecs/PersistentEntityCodec.groovy#L259-L261

Can someone explain this to me?

[kfujita-cohere]

I've posted a PR with a potential solution here: #660

[kfujita-cohere]

Resolved by #660