If you set nullable-type: true in your oapi-codegen config file and then use nullable: true in a field in a deep object, the deep object unmarshalling breaks. That's because nullable.Nullable is implemented as a map, and there is no special handling here.

Similarly, if you use format: uuid in a string field in a deep object, you'll get an error like this:

"Invalid format for parameter filter: error assigning value to destination: error assigning field [entity]: unhandled type: uuid.UUID"

Which I'm fairly sure comes from here.