Environment

• Engine: postgresql
• Plugin: sqlc-gen-kotlin_1.2.0.wasm / 22b437ecaea66417bbd3b958339d9868ba89368ce542c936c37305acf373104b
• sqlc version: 1.28.0

Issue

Setup

I have the following migration.

CREATE TYPE mood AS ENUM ('happy', 'sad', 'angry'); ALTER TABLE IF EXISTS people ADD COLUMN mood mood;

I have the following queries.

-- name: ListPeople :many SELECT id, name, mood FROM people; -- name: CreatePerson :exec INSERT INTO people (name, age, mood) VALUES ($1, $2, $3);

Generated Code

The generated models

enum class Mood(val value: String) { HAPPY("happy"), SAD("sad"), ANGRY("angry"); companion object { private val map = Mood.values().associateBy(Mood::value) fun lookup(value: String) = map[value] } } data class Person ( val id: Int, val name: String, val age: Int, val email: String?, val createdAt: LocalDateTime?, val mood: Mood? )

Generated queries

 @Throws(SQLException::class) override fun createPerson( name: String, age: Int, mood: Mood?) { conn.prepareStatement(createPerson).use { stmt -> stmt.setString(1, name) stmt.setInt(2, age) stmt.setObject(3, mood.value, Types.OTHER) stmt.execute() } } @Throws(SQLException::class) override fun listPeople(): List<ListPeopleRow> { return conn.prepareStatement(listPeople).use { stmt -> val results = stmt.executeQuery() val ret = mutableListOf<ListPeopleRow>() while (results.next()) { ret.add(ListPeopleRow( results.getInt(1), results.getString(2), Mood.lookup(results.getString(3))!! )) } ret }

Errors

Compile Error

In the function createPerson since mood is nullable, we need to do mood?.value instead of mood.value. Kotlin will fail to compile.

Runtime Nullpointer

When calling listPeople(..), a nullpointer exception will be thrown. This is because

• results.getString(3) is returning null and Mood.lookup(..) does not allow the argument to be nullable. The function signature is lookup(value: String)
• If the lookup(..) function is updated to accept nullable, it will still throw an error because of the !! on Mood.lookup(results.getString(3))!! since null will be returned from lookup(..)

Proposed changes

• If the enum is nullable, ensure we use ?. to get the value
• Update the generated lookup(..) to accept nullable, if the column is nullable
• If the column is nullable, do not add the !! when selecting the column

I have manually updated the generated code to do the above and things work for me.