fix: EXPOSED-382 ClassCastException when uuid().references() is used …

…with EntityID column (#2079)

Using references() invoked on a UUIDColumnType that targets an EntityIDColumnType<UUID>
causes a ClassCastException. This occurs because PreparedStatementApi.fillParameters()
tries to get the valueToDB() from EntityIDColumnType rather than the underlying UUIDColumnType
and it is not possible to cast the refValue UUID to EntityID<UUID>.

This exception does not happen with Int- or LongColumnType because their EntityID
variants are wrapped as AutoIncColumnTypes that delegate to the correct underlying
type. And this also doesn't happen if reference() is used because it creates an
EntityIDColumnType under-the-hood which avoids type mismatch.

This was most likely always happening but only causes an issue now that a stricter
column type-safety has been introduced, which does not tolerate well a foreign
key constraint between columns of different types.

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Column.kt

@@ -30,7 +30,7 @@ class Column<T>(
     val referee: Column<*>?
         get() = foreignKey?.targetOf(this)
 
-    /** Returns the column that this column references, casted as a column of type [S], or `null` if the cast fails. */
+    /** Returns the column that this column references, cast as a column of type [S], or `null` if the cast fails. */
     @Suppress("UNCHECKED_CAST")
     fun <S : T> referee(): Column<S>? = referee as? Column<S>
 

exposed-dao/src/main/kotlin/org/jetbrains/exposed/dao/Entity.kt

@@ -125,15 +125,15 @@ open class Entity<ID : Comparable<ID>>(val id: EntityID<ID>) {
                     }
                 }
                 else -> {
-                    // @formatter:off
+                    val castReferee = reference.referee<REF>()!!
+                    val baseReferee = (castReferee.columnType as? EntityIDColumnType<REF>)?.idColumn ?: castReferee
                     factory.findWithCacheCondition({
                         reference.referee!!.getValue(this, desc) == refValue
                     }) {
-                        reference.referee<REF>()!! eq refValue
+                        baseReferee eq refValue
                     }.singleOrNull()?.also {
                         storeReferenceInCache(reference, it)
                     }
-                    // @formatter:on
                 }
             } ?: error("Cannot find ${factory.table.tableName} WHERE id=$refValue")
         }

exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/entities/LongIdTableEntityTest.kt

@@ -4,7 +4,10 @@ import org.jetbrains.exposed.dao.LongEntity
 import org.jetbrains.exposed.dao.LongEntityClass
 import org.jetbrains.exposed.dao.id.EntityID
 import org.jetbrains.exposed.dao.id.LongIdTable
+import org.jetbrains.exposed.sql.Column
 import org.jetbrains.exposed.sql.exists
+import org.jetbrains.exposed.sql.insert
+import org.jetbrains.exposed.sql.insertAndGetId
 import org.jetbrains.exposed.sql.tests.DatabaseTestsBase
 import org.jetbrains.exposed.sql.tests.shared.assertEquals
 import org.junit.Test
@@ -13,30 +16,43 @@ object LongIdTables {
     object Cities : LongIdTable() {
         val name = varchar("name", 50)
     }
+
     class City(id: EntityID<Long>) : LongEntity(id) {
         companion object : LongEntityClass<City>(Cities)
         var name by Cities.name
     }
+
     object People : LongIdTable() {
         val name = varchar("name", 80)
         val cityId = reference("city_id", Cities)
     }
+
     class Person(id: EntityID<Long>) : LongEntity(id) {
         companion object : LongEntityClass<Person>(People)
         var name by People.name
         var city by City referencedOn People.cityId
     }
+
+    object Towns : LongIdTable("towns") {
+        val cityId: Column<Long> = long("city_id").references(Cities.id)
+    }
+
+    class Town(id: EntityID<Long>) : LongEntity(id) {
+        companion object : LongEntityClass<Town>(Towns)
+        var city by City referencedOn Towns.cityId
+    }
 }
 class LongIdTableEntityTest : DatabaseTestsBase() {
-
-    @Test fun `create tables`() {
+    @Test
+    fun `create tables`() {
         withTables(LongIdTables.Cities, LongIdTables.People) {
             assertEquals(true, LongIdTables.Cities.exists())
             assertEquals(true, LongIdTables.People.exists())
         }
     }
 
-    @Test fun `create records`() {
+    @Test
+    fun `create records`() {
         withTables(LongIdTables.Cities, LongIdTables.People) {
             val mumbai = LongIdTables.City.new { name = "Mumbai" }
             val pune = LongIdTables.City.new { name = "Pune" }
@@ -64,7 +80,8 @@ class LongIdTableEntityTest : DatabaseTestsBase() {
         }
     }
 
-    @Test fun `update and delete records`() {
+    @Test
+    fun `update and delete records`() {
         withTables(LongIdTables.Cities, LongIdTables.People) {
             val mumbai = LongIdTables.City.new { name = "Mumbai" }
             val pune = LongIdTables.City.new { name = "Pune" }
@@ -93,4 +110,19 @@ class LongIdTableEntityTest : DatabaseTestsBase() {
             assertEquals(false, allPeople.contains(Pair("Tanu Arora", "Pune")))
         }
     }
+
+    @Test
+    fun testForeignKeyBetweenLongAndEntityIDColumns() {
+        withTables(LongIdTables.Cities, LongIdTables.Towns) {
+            val cId = LongIdTables.Cities.insertAndGetId {
+                it[name] = "City A"
+            }
+            LongIdTables.Towns.insert {
+                it[cityId] = cId.value
+            }
+
+            val town1 = LongIdTables.Town.all().single()
+            assertEquals(cId, town1.city.id)
+        }
+    }
 }

exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/entities/UuidTableEntityTest.kt

@@ -4,7 +4,10 @@ import org.jetbrains.exposed.dao.UUIDEntity
 import org.jetbrains.exposed.dao.UUIDEntityClass
 import org.jetbrains.exposed.dao.id.EntityID
 import org.jetbrains.exposed.dao.id.UUIDTable
+import org.jetbrains.exposed.sql.Column
 import org.jetbrains.exposed.sql.exists
+import org.jetbrains.exposed.sql.insert
+import org.jetbrains.exposed.sql.insertAndGetId
 import org.jetbrains.exposed.sql.tests.DatabaseTestsBase
 import org.jetbrains.exposed.sql.tests.shared.assertEquals
 import org.junit.Test
@@ -47,10 +50,18 @@ object UUIDTables {
         var city by City.referencedOn(Addresses.city)
         var address by Addresses.address
     }
+
+    object Towns : UUIDTable("towns") {
+        val cityId: Column<UUID> = uuid("city_id").references(Cities.id)
+    }
+
+    class Town(id: EntityID<UUID>) : UUIDEntity(id) {
+        companion object : UUIDEntityClass<Town>(Towns)
+        var city by City referencedOn Towns.cityId
+    }
 }
 
 class UUIDTableEntityTest : DatabaseTestsBase() {
-
     @Test
     fun `create tables`() {
         withTables(UUIDTables.Cities, UUIDTables.People) {
@@ -149,4 +160,19 @@ class UUIDTableEntityTest : DatabaseTestsBase() {
             assertEquals("address2", address2.address)
         }
     }
+
+    @Test
+    fun testForeignKeyBetweenUUIDAndEntityIDColumns() {
+        withTables(UUIDTables.Cities, UUIDTables.Towns) {
+            val cId = UUIDTables.Cities.insertAndGetId {
+                it[name] = "City A"
+            }
+            UUIDTables.Towns.insert {
+                it[cityId] = cId.value
+            }
+
+            val town1 = UUIDTables.Town.all().single()
+            assertEquals(cId, town1.city.id)
+        }
+    }
 }