Android Room SQLite UPSERT without using actual https://www.sqlite.org/lang_UPSERT.html

User.kt

package com.namtarr.upsert

import androidx.room.Entity
import androidx.room.PrimaryKey

@Entity
class User(
    @PrimaryKey
    val id: Long,
    val name: String
)

UserDao.kt

package com.namtarr.upsert

import androidx.room.Dao
import androidx.room.Insert
import androidx.room.OnConflictStrategy
import androidx.room.Transaction
import androidx.room.Update

@Dao
abstract class UserDao {

    @Transaction
    open fun upsertUser(user: User) {
        if (insertUser(user) == -1L) {
            updateUser(user)
        }
    }

    @Transaction
    open fun upsertUsers(users: List<User>) {
        val inserted = insertUsers(users).filter { it != -1L }
        val usersToUpdate = users.filter { !inserted.contains(it.id) }
        updateUsers(usersToUpdate)
    }

    @Update(onConflict = OnConflictStrategy.REPLACE)
    protected abstract fun updateUser(user: User)

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    protected abstract fun insertUser(user: User): Long

    @Update(onConflict = OnConflictStrategy.REPLACE)
    protected abstract fun updateUsers(users: Collection<User>)

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    protected abstract fun insertUsers(users: Collection<User>): List<Long>
}