BigDecimalAsNumberSerializer

Writes a BigDecimal into JSON as a bare number, keeping every digit it had.

There is no serializer for BigDecimal in the box, and the two obvious ways of writing one both lose something a numeric column was chosen to keep. Encoding it as a Double rounds it - which is the whole reason the column is numeric and not float8. Encoding it as a string keeps the digits but makes the JSON say text: jsonb_typeof answers string, (payload->>'amount')::numeric needs a cast written by hand, and arithmetic or an index on the value inside jsonb is not available at all.

So it writes an unquoted literal - 12345.6789012345, not "12345.6789012345" - which JSON permits at any length and PostgreSQL's jsonb stores as a numeric, exactly. Reading goes back through the raw token rather than through a Double, so a value too long for one survives the round trip.

This works against JSON only: it reaches for the encoder's JSON element to bypass the number type its primitives offer. Another format throws.

Registered contextually by octaviusSerializersModule, so @Contextual is normally all a property needs. Naming it outright is for the class that does not read that module's kotlinx.serialization.json.Json:

@Serializable
@DynamicallyMappable("tribute_assessment")
data class TributeAssessment(
    val province: String,
    @Serializable(with = BigDecimalAsNumberSerializer::class)
    val denarii: BigDecimal
)