NPE in BasicRelationalConverter: @WritingConverter in combination with null [DATAJDBC-578]

Clemens Hahn opened DATAJDBC-578 and commented

I have a Entity Ticket with a column status which is a enum:

data class Ticket(
        @Id var id: Long? = null,
        val title: String,
        val assigned: String? = null,
        val status: TicketStatus = TicketStatus.UNKNOWN
) {
    enum class TicketStatus(private val databaseValue: String?) {
        OPEN("oPeN"),
        SOLVED("solVed"),
        UNKNOWN(null);

        @ReadingConverter
        class EnumReadingConverter : Converter<String, TicketStatus> {
            override fun convert(dbValue: String): TicketStatus {
                return values().first { it.databaseValue == dbValue }
            }
        }

        @WritingConverter
        class EnumWritingConverter : Converter<TicketStatus, String> {
            override fun convert(entity: TicketStatus): String? {
                return entity.databaseValue
            }
        }
    }
}

As you can see the TicketStatus UNKNOWN should be represented by null in the database.

Perhaps this is a bad approach at all, but I noticed a hard NullPointerException in org.springframework.data.relational.core.conversion.BasicRelationalConverter.getPotentiallyConvertedSimpleWrite(BasicRelationalConverter.java:214). Full stacktrace is attached.

In order to reproduce this case please see my created spring-boot project at GitHub (ticket/DATAJDBC-578 branch), especially the tests in com.example.springdatajdbc.showcase.ShowcaseApplicationTests

So the root cause of this exception is not spring-data-jdbc. Please change the jira-project if necessary, thanks!

Attachments:

• NPE-BasicRelationalConverter.txt (11.40 kB)