Id conversion handling in `QueryMapper.getMappedValue(…)` doesn't consider nesting

[antechrestos]

While upgrading to springboot 3.3.0, I detect a strange behaviour.

I use spring-boot-starter-data-mongodb-reactive with CoroutineCrudRepository.

When using coposite id, I cannot save documents. Every save ends with error

Write operation error on server localhost:32811. Write error: WriteError{code=66, message='After applying the update, the (immutable) field '_id' was found to have been altered to _id: { user: { _id: "1", tenant: "tenant" }, demoId: "demo-id", timestamp: new Date(1716798131072) }', details={}}.

I made a demo repository

[mp911de]

convertIdField(…) applies structures and types of the Id field even for nested documents if the Id is a document with nested documents. We have to fix that.