#154 allow direct polymorphism serialization

Litote · Nov 11, 2019 · 1585f7e · 1585f7e
1 parent 2364170
commit 1585f7e
Show file tree

Hide file tree

Showing 3 changed files with 102 additions and 8 deletions.
diff --git a/kmongo-serialization-mapping/src/main/kotlin/KMongoSerializationRepository.kt b/kmongo-serialization-mapping/src/main/kotlin/KMongoSerializationRepository.kt
@@ -22,6 +22,8 @@ import com.github.jershell.kbson.DateSerializer
 import com.github.jershell.kbson.ObjectIdSerializer
 import kotlinx.serialization.ImplicitReflectionSerializer
 import kotlinx.serialization.KSerializer
+import kotlinx.serialization.PolymorphicSerializer
+import kotlinx.serialization.SerializationException
 import kotlinx.serialization.internal.PairSerializer
 import kotlinx.serialization.internal.ReferenceArraySerializer
 import kotlinx.serialization.internal.StringSerializer
@@ -100,7 +102,7 @@ internal object KMongoSerializationRepository {
     )
 
     @ImplicitReflectionSerializer
-    private fun getBaseSerializer(obj: Any): KSerializer<*>? {
+    private fun <T : Any> getBaseSerializer(obj: T, kClass: KClass<T> = obj.javaClass.kotlin): KSerializer<*>? {
         @Suppress("UNCHECKED_CAST")
         return when (obj) {
             is KProperty<*> -> KPropertySerializer
@@ -111,19 +113,33 @@ internal object KMongoSerializationRepository {
                 getSerializer(obj.third)
             )
             is Array<*> -> ReferenceArraySerializer(
-                obj.javaClass.kotlin as KClass<Any>,
+                kClass as KClass<Any>,
                 obj.filterNotNull().let {
                     if (it.isEmpty()) StringSerializer else getSerializer(it.first())
                 } as KSerializer<Any>
             )
-            else -> module.getContextual(obj.javaClass.kotlin)
-                    ?: module.getPolymorphic(obj.javaClass.kotlin, obj)
+            else -> module.getContextual(kClass)
+                    ?: module.getPolymorphic(kClass, obj)?.let {
+                        PolymorphicSerializer(kClass)
+                    }
         }
     }
 
     @Suppress("UNCHECKED_CAST")
     @ImplicitReflectionSerializer
-    fun <T : Any> getSerializer(obj: T?): KSerializer<T> =
+    fun <T : Any> getSerializer(kClass: KClass<T>, obj: T?): KSerializer<T> =
+        if (obj == null) {
+            JsonNullSerializer as? KSerializer<T> ?: error("no serializer for null")
+        } else {
+            (serializersMap[kClass]
+                    ?: getBaseSerializer(obj, kClass)
+                    ?: kClass.serializer()) as? KSerializer<T>
+                    ?: error("no serializer for $obj of class $kClass")
+        }
+
+    @Suppress("UNCHECKED_CAST")
+    @ImplicitReflectionSerializer
+    private fun <T : Any> getSerializer(obj: T?): KSerializer<T> =
         if (obj == null) {
             JsonNullSerializer as? KSerializer<T> ?: error("no serializer for null")
         } else {
@@ -138,7 +154,16 @@ internal object KMongoSerializationRepository {
     fun <T : Any> getSerializer(kClass: KClass<T>): KSerializer<T> =
         (serializersMap[kClass]
                 ?: module.getContextual(kClass)
-                ?: kClass.serializer()) as? KSerializer<T>
+                ?: try {
+                    kClass.serializer()
+                } catch (e: SerializationException) {
+                    if (kClass.isAbstract || kClass.isOpen || kClass.isSealed) {
+                        PolymorphicSerializer(kClass)
+                    } else {
+                        throw e
+                    }
+                }
+                ) as? KSerializer<T>
                 ?: error("no serializer for $kClass of class $kClass")
 
     @Volatile

diff --git a/kmongo-serialization-mapping/src/main/kotlin/SerializationCodec.kt b/kmongo-serialization-mapping/src/main/kotlin/SerializationCodec.kt
@@ -54,7 +54,7 @@ internal class SerializationCodec<T : Any>(val clazz: KClass<T>) : CollectibleCo
 
     @ImplicitReflectionSerializer
     override fun encode(writer: BsonWriter, value: T, encoderContext: EncoderContext) {
-        val serializer = KMongoSerializationRepository.getSerializer(value)
+        val serializer = KMongoSerializationRepository.getSerializer(clazz, value)
         BsonEncoder(writer, module, Configuration()).encode(serializer, value)
     }
 

diff --git a/kmongo-serialization-mapping/src/test/kotlin/SerializationCodecTest.kt b/kmongo-serialization-mapping/src/test/kotlin/SerializationCodecTest.kt
@@ -23,6 +23,7 @@ import org.litote.kmongo.Id
 import org.litote.kmongo.model.Friend
 import org.litote.kmongo.newId
 import kotlin.test.assertEquals
+import kotlin.test.assertFails
 import kotlin.test.assertFalse
 
 /**
@@ -151,7 +152,7 @@ class SerializationCodecTest {
     data class IntMessage(val number: Int) : Message
 
     @Serializable
-    data class Container(val m:Message)
+    data class Container(val m: Message)
 
     @ImplicitReflectionSerializer
     @Test
@@ -174,4 +175,72 @@ class SerializationCodecTest {
         assertEquals(c, newC)
     }
 
+    interface Message2
+
+    @Serializable
+    data class StringMessage2(val message: String) : Message2
+
+    @Serializable
+    data class IntMessage2(val number: Int) : Message2
+
+    @ImplicitReflectionSerializer
+    @Test
+    fun `encode and decode directly custom polymorphic serializer`() {
+        registerModule(
+            SerializersModule {
+                polymorphic(Message2::class) {
+                    StringMessage2::class with StringMessage2.serializer()
+                    IntMessage2::class with IntMessage2.serializer()
+                }
+            })
+        val c = StringMessage2("a")
+        val codec = SerializationCodec(Message2::class)
+        val document = BsonDocument()
+        val writer = BsonDocumentWriter(document)
+        codec.encode(writer, c, EncoderContext.builder().build())
+
+        val newC = codec.decode(BsonDocumentReader(document), DecoderContext.builder().build())
+
+        assertEquals(c, newC)
+    }
+
+    @Serializable
+    data class SerializableClass(val s: String)
+
+    data class NotSerializableClass(val s: String)
+
+    @ImplicitReflectionSerializer
+    @Test
+    fun `encoding a not serializable class throws a SerializationException`() {
+        val t = assertFails {
+            val c = NotSerializableClass("a")
+            val codec = SerializationCodec(NotSerializableClass::class)
+            val document = BsonDocument()
+            val writer = BsonDocumentWriter(document)
+            codec.encode(writer, c, EncoderContext.builder().build())
+        }
+        assertEquals(
+            "Can't locate argument-less serializer for class org.litote.kmongo.serialization.SerializationCodecTest\$NotSerializableClass. For generic classes, such as lists, please provide serializer explicitly.",
+            t.message
+        )
+    }
+
+    @ImplicitReflectionSerializer
+    @Test
+    fun `decoding a not serializable class throws a SerializationException`() {
+        val t = assertFails {
+            val c = SerializableClass("a")
+            val codec = SerializationCodec(SerializableClass::class)
+            val document = BsonDocument()
+            val writer = BsonDocumentWriter(document)
+            codec.encode(writer, c, EncoderContext.builder().build())
+
+            val codec2 = SerializationCodec(NotSerializableClass::class)
+            codec2.decode(BsonDocumentReader(document), DecoderContext.builder().build())
+        }
+        assertEquals(
+            "Can't locate argument-less serializer for class org.litote.kmongo.serialization.SerializationCodecTest\$NotSerializableClass. For generic classes, such as lists, please provide serializer explicitly.",
+            t.message
+        )
+    }
 }