Circe throws an exception when parsing nested JSONB field that is null.

If a query returns a nested structure from a JSON(b) field, the empty field must be absent for the query to work. If the field is present and null, there is a circe exception thrown.

Example query:

sql"SELECT address->'coordinates' FROM profile"

Definition of the Coordinates and Address types:

case class Coordinates(latitude: Double, longitude: Double)
case class Address(coordinates: Option[Coordinates])

Definition of the custom mapping:

given Meta[Coordinates] = new Meta(pgDecoderGet, pgEncoderPut)
given Meta[Address] = new Meta(pgDecoderGet, pgEncoderPut)

The query works for the following contents of the address column:
NULL
{}

The query throws and exception for the following contents of the address column:
{"coordinates":null}
The exception message is: io.circe.DecodingFailure$DecodingFailureImpl: DecodingFailure at : Got value 'null' with wrong type, expecting object

Start by reproducing the query with the shown Coordinates, Address, and custom Meta definitions, comparing NULL, {}, and {"coordinates":null} values. Trace the decoding path that handles the nested JSONB field; done means a present null coordinates value no longer raises the reported Circe DecodingFailure.