Message serialization, fix #767

2025-01-31 03:22:36 +08:00 · 2021-01-06 13:13:39 +08:00 · 2021-01-06 13:13:39 +08:00 · ebc7d655e3
commit ebc7d655e3
parent bfd21cbb92
30 changed files with 452 additions and 394 deletions
--- a/mirai-core-api/src/commonMain/kotlin/message/MessageSerializer.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/MessageSerializer.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -10,15 +10,12 @@
 package net.mamoe.mirai.message

 import kotlinx.serialization.KSerializer
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.descriptors.SerialDescriptor
-import kotlinx.serialization.descriptors.buildClassSerialDescriptor
+import kotlinx.serialization.descriptors.*
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
-import kotlinx.serialization.modules.PolymorphicModuleBuilder
-import kotlinx.serialization.modules.SerializersModule
-import kotlinx.serialization.modules.plus
-import kotlinx.serialization.modules.polymorphic
+import kotlinx.serialization.modules.*
 import net.mamoe.mirai.Mirai
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.utils.MiraiExperimentalApi
@ -29,21 +26,44 @@ import kotlin.reflect.KClass
 public interface MessageSerializer {
    public val serializersModule: SerializersModule

-    public fun <M : Message> registerSerializer(clazz: KClass<M>, serializer: KSerializer<M>)
+    public fun <M : SingleMessage> registerSerializer(baseClass: KClass<M>, serializer: KSerializer<M>)

    public fun registerSerializers(serializersModule: SerializersModule)

    public fun clearRegisteredSerializers()
+
+    public companion object INSTANCE : MessageSerializer by MessageSerializerImpl
+}
+
+internal fun ClassSerialDescriptorBuilder.takeElementsFrom(descriptor: SerialDescriptor) {
+    with(descriptor) {
+        repeat(descriptor.elementsCount) { index ->
+            element(
+                elementName = getElementName(index),
+                descriptor = getElementDescriptor(index),
+                annotations = getElementAnnotations(index),
+                isOptional = isElementOptional(index),
+            )
+        }
+    }
 }

@MiraiInternalApi
-public open class MessageSourceSerializerImpl(serialName: String) : KSerializer<MessageSource> {
-    public companion object : MessageSourceSerializerImpl("net.mamoe.mirai.message.data.MessageSource")
-
+public open class MessageSourceSerializerImpl(serialName: String) :
+    KSerializer<MessageSource> by SerialData.serializer().map(
+        resultantDescriptor = buildClassSerialDescriptor(serialName) {
+            takeElementsFrom(SerialData.serializer().descriptor)
+        },
+        serialize = { SerialData(kind, botId, ids, internalIds, time, fromId, targetId, originalMessage) },
+        deserialize = {
+            Mirai.constructMessageSource(botId, kind, fromId, targetId, ids, time, internalIds, originalMessage)
+        }
+    ) {
+    @SerialName(MessageSource.SERIAL_NAME)
    @Serializable
    internal class SerialData(
        val kind: MessageSourceKind,
-        val bot: Long,
+        val botId: Long,
        val ids: IntArray,
        val internalIds: IntArray,
        val time: Int,
@ -51,49 +71,6 @@ public open class MessageSourceSerializerImpl(serialName: String) : KSerializer<
        val targetId: Long,
        val originalMessage: MessageChain,
    )
-
-    override val descriptor: SerialDescriptor = buildClassSerialDescriptor(serialName) {
-        val desc = SerialData.serializer().descriptor
-        repeat(SerialData.serializer().descriptor.elementsCount) { index ->
-            element(
-                desc.getElementName(index),
-                desc.getElementDescriptor(index),
-                desc.getElementAnnotations(index),
-                desc.isElementOptional(index)
-            )
-        }
-    }
-//        buildClassSerialDescriptor("MessageSource") {
-//            element("bot", Long.serializer().descriptor)
-//            element("ids", ArraySerializer(Int.serializer()).descriptor)
-//            element("internalIds", ArraySerializer(Int.serializer()).descriptor)
-//            element("time", Int.serializer().descriptor)
-//            element("fromId", Int.serializer().descriptor)
-//            element("targetId", Int.serializer().descriptor)
-//            element("originalMessage", MessageChain.Serializer.descriptor)
-//        }
-
-    override fun deserialize(decoder: Decoder): MessageSource {
-        val data = SerialData.serializer().deserialize(decoder)
-        data.run {
-            return Mirai.constructMessageSource(
-                botId = bot, kind = kind, fromUin = fromId, targetUin = targetId, ids = ids,
-                time = time, internalIds = internalIds, originalMessage = originalMessage.asMessageChain()
-            )
-        }
-    }
-
-    override fun serialize(encoder: Encoder, value: MessageSource) {
-        value.run {
-            SerialData.serializer().serialize(
-                encoder = encoder,
-                value = SerialData(
-                    kind = kind, bot = botId, ids = ids, internalIds = internalIds,
-                    time = time, fromId = fromId, targetId = targetId, originalMessage = originalMessage
-                )
-            )
-        }
-    }
 }


@ -121,8 +98,6 @@ private val builtInSerializersModule by lazy {
        contextual(LightApp::class, LightApp.serializer())
        contextual(SimpleServiceMessage::class, SimpleServiceMessage.serializer())
        contextual(AbstractServiceMessage::class, AbstractServiceMessage.serializer())
-        contextual(LongMessage::class, LongMessage.serializer())
-        contextual(ForwardMessageInternal::class, ForwardMessageInternal.serializer())

        contextual(PttMessage::class, PttMessage.serializer())
        contextual(Voice::class, Voice.serializer())
@ -130,12 +105,7 @@ private val builtInSerializersModule by lazy {
        contextual(VipFace::class, VipFace.serializer())
        contextual(FlashImage::class, FlashImage.serializer())

-        fun PolymorphicModuleBuilder<SingleMessage>.singleMessageSubclasses() {
-            // subclass(MessageSource::class, MessageSource.serializer())
-        }
-
-        //   contextual(MessageSource::class, MessageSource.serializer())
-        polymorphicDefault(MessageSource::class) { MessageSource.serializer() }
+        contextual(MessageSource::class, MessageSource.serializer())

        fun PolymorphicModuleBuilder<MessageMetadata>.messageMetadataSubclasses() {
            subclass(MessageSource::class, MessageSource.serializer())
@ -154,8 +124,6 @@ private val builtInSerializersModule by lazy {

            subclass(LightApp::class, LightApp.serializer())
            subclass(SimpleServiceMessage::class, SimpleServiceMessage.serializer())
-            subclass(LongMessage::class, LongMessage.serializer())
-            subclass(ForwardMessageInternal::class, ForwardMessageInternal.serializer())

            //  subclass(PttMessage::class, PttMessage.serializer())
            subclass(Voice::class, Voice.serializer())
@ -166,21 +134,11 @@ private val builtInSerializersModule by lazy {
            subclass(FlashImage::class, FlashImage.serializer())
        }

-        @Suppress("DEPRECATION_ERROR")
-        contextual(Message::class, Message.Serializer)
-        // contextual(SingleMessage::class, SingleMessage.Serializer)
+        contextual(SingleMessage::class, SingleMessage.Serializer)
        contextual(MessageChain::class, MessageChain.Serializer)
        contextual(MessageChainImpl::class, MessageChainImpl.serializer())

-        polymorphic(MessageChain::class) {
-            subclass(MessageChainImpl::class, MessageChainImpl.serializer())
-        }
-        polymorphicDefault(MessageChain::class) { MessageChainImpl.serializer() }
-
-        polymorphic(AbstractServiceMessage::class) {
-            subclass(LongMessage::class, LongMessage.serializer())
-            subclass(ForwardMessageInternal::class, ForwardMessageInternal.serializer())
-        }
+//        polymorphicDefault(MessageChain::class) { MessageChainImpl.serializer() }

        //  polymorphic(SingleMessage::class) {
        //      subclass(MessageSource::class, MessageSource.serializer())
@ -189,16 +147,12 @@ private val builtInSerializersModule by lazy {
        //      }
        //  }

-        polymorphicDefault(Image::class) { Image.Serializer }
-
        // polymorphic(Message::class) {
        //     subclass(PlainText::class, PlainText.serializer())
        // }
-        polymorphic(Message::class) {
+        polymorphic(SingleMessage::class) {
            messageContentSubclasses()
            messageMetadataSubclasses()
-            singleMessageSubclasses()
-            subclass(MessageChainImpl::class, MessageChainImpl.serializer())
        }

        //contextual(SingleMessage::class, SingleMessage.Serializer)
@ -216,7 +170,7 @@ private val builtInSerializersModule by lazy {
        // contextual(MessageMetadata::class, MessageMetadata.Serializer)
        // polymorphic(MessageMetadata::class, MessageMetadata.Serializer) {
        //     messageMetadataSubclasses()
-        // }
+        //
    }
 }

@ -226,22 +180,51 @@ internal object MessageSerializerImpl : MessageSerializer {
    override val serializersModule: SerializersModule get() = serializersModuleField ?: builtInSerializersModule

    @Synchronized
-    override fun <M : Message> registerSerializer(clazz: KClass<M>, serializer: KSerializer<M>) {
-        serializersModuleField = serializersModule.plus(SerializersModule {
-            contextual(clazz, serializer)
-            polymorphic(Message::class) {
-                subclass(clazz, serializer)
+    override fun <M : SingleMessage> registerSerializer(baseClass: KClass<M>, serializer: KSerializer<M>) {
+        serializersModuleField = serializersModule.overwriteWith(SerializersModule {
+            contextual(baseClass, serializer)
+            polymorphic(SingleMessage::class) {
+                subclass(baseClass, serializer)
            }
        })
    }

    @Synchronized
    override fun registerSerializers(serializersModule: SerializersModule) {
-        serializersModuleField = serializersModule
+        serializersModuleField = serializersModule.overwriteWith(serializersModule)
    }

    @Synchronized
    override fun clearRegisteredSerializers() {
        serializersModuleField = builtInSerializersModule
    }
+}
+
+internal inline fun <T, R> KSerializer<T>.map(
+    resultantDescriptor: SerialDescriptor,
+    crossinline deserialize: T.(T) -> R,
+    crossinline serialize: R.(R) -> T,
+): KSerializer<R> {
+    return object : KSerializer<R> {
+        override val descriptor: SerialDescriptor get() = resultantDescriptor
+        override fun deserialize(decoder: Decoder): R = this@map.deserialize(decoder).let { deserialize(it, it) }
+        override fun serialize(encoder: Encoder, value: R) = serialize(encoder, value.let { serialize(it, it) })
+    }
+}
+
+internal inline fun <T, R> KSerializer<T>.mapPrimitive(
+    serialName: String,
+    crossinline deserialize: (T) -> R,
+    crossinline serialize: R.(R) -> T,
+): KSerializer<R> {
+    val kind = this@mapPrimitive.descriptor.kind
+    check(kind is PrimitiveKind) { "kind must be PrimitiveKind but found $kind" }
+    return object : KSerializer<R> {
+        override fun deserialize(decoder: Decoder): R =
+            this@mapPrimitive.deserialize(decoder).let(deserialize)
+
+        override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor(serialName, kind)
+        override fun serialize(encoder: Encoder, value: R) =
+            this@mapPrimitive.serialize(encoder, value.let { serialize(it, it) })
+    }
 }
--- a/mirai-core-api/src/commonMain/kotlin/message/data/At.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/At.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -14,6 +14,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.contact.Group
 import net.mamoe.mirai.contact.Member
@ -30,6 +31,7 @@ import net.mamoe.mirai.message.code.CodableMessage
 *
 * @see AtAll 全体成员
 */
+@SerialName(At.SERIAL_NAME)
@Serializable
 public data class At(
    public val target: Long,
@ -51,7 +53,9 @@ public data class At(
        builder.append("[mirai:at:").append(target).append(']')
    }

-    public companion object;
+    public companion object {
+        public const val SERIAL_NAME: String = "At"
+    }

    // 自动为消息补充 " "
    public override fun followedBy(tail: Message): MessageChain {
--- a/mirai-core-api/src/commonMain/kotlin/message/data/AtAll.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/AtAll.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -13,6 +13,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.message.code.CodableMessage

@ -28,10 +29,12 @@ private const val displayA = "@全体成员"
 *
 * @see At at 单个群成员
 */
+@SerialName(AtAll.SERIAL_NAME)
@Serializable
 public object AtAll :
    MessageContent, CodableMessage {
    public const val display: String = displayA
+    public const val SERIAL_NAME: String = "AtAll"

    @Suppress("SpellCheckingInspection")
    public override fun toString(): String = "[mirai:atall]"
--- a/mirai-core-api/src/commonMain/kotlin/message/data/Face.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/Face.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -12,6 +12,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.message.code.CodableMessage

@ -22,10 +23,11 @@ import net.mamoe.mirai.message.code.CodableMessage
 * 格式: &#91;mirai:face:*[id]*&#93;
 */
@Serializable
+@SerialName(Face.SERIAL_NAME)
 public data class Face(public val id: Int) : // used in delegation
    MessageContent, CodableMessage {

-    public override fun toString(): String = "[mirai:face:$id]";
+    public override fun toString(): String = "[mirai:face:$id]"
    public val name: String get() = contentToString().let { it.substring(1, it.length - 1) }
    public override fun contentToString(): String = names.getOrElse(id) { "[表情]" }

@ -39,6 +41,9 @@ public data class Face(public val id: Int) : // used in delegation
    //Auto generated
    @Suppress("NonAsciiCharacters", "unused", "SpellCheckingInspection", "all")
    public companion object {
+        public const val SERIAL_NAME: String = "Face"
+
+
        public const val JING_YA: Int = 0
        public const val 惊讶: Int = JING_YA
        public const val PIE_ZUI: Int = 1
--- a/mirai-core-api/src/commonMain/kotlin/message/data/ForwardMessage.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/ForwardMessage.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -13,6 +13,7 @@ package net.mamoe.mirai.message.data

 import io.ktor.http.*
 import io.ktor.util.*
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.Bot
 import net.mamoe.mirai.contact.Contact
@ -96,6 +97,7 @@ public data class RawForwardMessage(
 *
 * @see buildForwardMessage
 */
+@SerialName(ForwardMessage.SERIAL_NAME)
@Serializable
 public data class ForwardMessage(
    val preview: List<String>,
@ -136,7 +138,7 @@ public data class ForwardMessage(
         * Java 用户: 使用 [sequenceOf] (`SequenceKt.sequenceOf`) 或 [asSequence] (`SequenceKt.asSequence`)
         */
        public fun generatePreview(forward: RawForwardMessage): List<String> =
-            forward.nodeList.map { it.senderName + ": " + it.message.contentToString() }
+            forward.nodeList.map { it.senderName + ": " + it.messageChain.contentToString() }

        /**
         * 显示在卡片底部
@ -152,8 +154,15 @@ public data class ForwardMessage(
        override val senderId: Long,
        override val time: Int,
        override val senderName: String,
-        override val message: Message
-    ) : INode
+        override val messageChain: MessageChain
+    ) : INode {
+        public constructor(
+            senderId: Long,
+            time: Int,
+            senderName: String,
+            message: Message
+        ) : this(senderId, time, senderName, message.asMessageChain())
+    }

    @MiraiExperimentalApi
    public interface INode {
@ -175,11 +184,13 @@ public data class ForwardMessage(
        /**
         * 消息内容
         */
-        public val message: Message
+        public val messageChain: MessageChain
    }

    public companion object Key :
-        AbstractPolymorphicMessageKey<MessageContent, ForwardMessage>(MessageContent, { it.safeCast() })
+        AbstractPolymorphicMessageKey<MessageContent, ForwardMessage>(MessageContent, { it.safeCast() }) {
+        public const val SERIAL_NAME: String = "ForwardMessage"
+    }
 }


@ -358,7 +369,7 @@ public class ForwardMessageBuilder private constructor(
        /**
         * 消息内容
         */
-        public override lateinit var message: Message
+        public override lateinit var messageChain: MessageChain


        /**
@ -410,19 +421,21 @@ public class ForwardMessageBuilder private constructor(
         * 指定消息内容
         */
        @ForwardMessageDsl
-        public infix fun message(message: Message): BuilderNode = this.apply { this.message = message }
+        public infix fun message(message: Message): BuilderNode =
+            this.apply { this.messageChain = message.asMessageChain() }

        /**
         * 指定消息内容
         */
        @ForwardMessageDsl
-        public infix fun message(message: String): BuilderNode = this.apply { this.message = PlainText(message) }
+        public infix fun message(message: String): BuilderNode =
+            this.apply { this.messageChain = PlainText(message).asMessageChain() }

        /** 添加一条消息  */
        @ForwardMessageDsl
        public infix fun says(message: Message): ForwardMessageBuilder = this@ForwardMessageBuilder.apply {
            checkBuilt()
-            this@BuilderNode.message = message
+            this@BuilderNode.messageChain = message.asMessageChain()
            add(this@BuilderNode)
        }

@ -454,7 +467,7 @@ public class ForwardMessageBuilder private constructor(
            checkBuilt()
            add(BuilderNode().apply {
                senderId = this@says
-                this.message = message
+                this.messageChain = message.asMessageChain()
            })
        }

@ -551,7 +564,7 @@ public class ForwardMessageBuilder private constructor(
            it.senderId,
            it.time,
            it.senderName,
-            it.message
+            it.messageChain
        )
    }).render(this.displayStrategy)

@ -565,5 +578,5 @@ public class ForwardMessageBuilder private constructor(
 internal inline fun Int.toLongUnsigned(): Long = this.toLong().and(0xFFFF_FFFF)

 private fun ForwardMessage.INode.toNode(): ForwardMessage.Node {
-    return ForwardMessage.Node(senderId, time, senderName, message)
+    return ForwardMessage.Node(senderId, time, senderName, messageChain)
 }
--- a/mirai-core-api/src/commonMain/kotlin/message/data/HummerMessage.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/HummerMessage.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -13,7 +13,7 @@

 package net.mamoe.mirai.message.data

-import kotlinx.serialization.Contextual
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.message.code.CodableMessage
 import net.mamoe.mirai.message.code.internal.appendAsMiraiCode
@ -46,6 +46,7 @@ public interface HummerMessage : MessageContent, ConstrainSingle {
 *
 * @see PokeMessage.Companion 使用伴生对象中的常量
 */
+@SerialName(PokeMessage.SERIAL_NAME)
@Serializable
 public data class PokeMessage @MiraiInternalApi constructor(
    /**
@ -63,6 +64,8 @@ public data class PokeMessage @MiraiInternalApi constructor(
    public companion object Key :
        AbstractPolymorphicMessageKey<HummerMessage, PokeMessage>(HummerMessage, { it.castOrNull() }) {

+        public const val SERIAL_NAME: String = "PokeMessage"
+
        /** 戳一戳 */
        @JvmField
        public val ChuoYiChuo: PokeMessage = PokeMessage("戳一戳", 1, -1)
@ -195,7 +198,9 @@ public interface MarketFace : HummerMessage {
        get() = Key

    public companion object Key :
-        AbstractPolymorphicMessageKey<HummerMessage, MarketFace>(HummerMessage, { it.safeCast() })
+        AbstractPolymorphicMessageKey<HummerMessage, MarketFace>(HummerMessage, { it.safeCast() }) {
+        public const val SERIAL_NAME: String = "MarketFace"
+    }

    override fun contentToString(): String = name
 }
@ -215,6 +220,7 @@ public interface MarketFace : HummerMessage {
 *
 * @see VipFace.Key 使用伴生对象中的常量
 */
+@SerialName(VipFace.SERIAL_NAME)
@Serializable
 public data class VipFace @MiraiInternalApi constructor(
    /**
@ -239,6 +245,8 @@ public data class VipFace @MiraiInternalApi constructor(
    public companion object Key :
        AbstractPolymorphicMessageKey<HummerMessage, VipFace>(HummerMessage, { it.safeCast() }) {

+        public const val SERIAL_NAME: String = "VipFace"
+
        @JvmField
        public val LiuLian: Kind = 9 to "榴莲"

@ -310,12 +318,14 @@ public data class VipFace @MiraiInternalApi constructor(
 *
 * @see Image 查看图片相关信息
 */
+@SerialName(FlashImage.SERIAL_NAME)
@Serializable
 public data class FlashImage(
    /**
     * 闪照的内容图片, 即一个普通图片.
     */
-    @Contextual
+    @SerialName("imageId")
+    @Serializable(Image.AsStringSerializer::class)
    public val image: Image
 ) : MessageContent, HummerMessage, CodableMessage, ConstrainSingle {
    override val key: MessageKey<FlashImage>
@ -323,6 +333,7 @@ public data class FlashImage(

    public companion object Key :
        AbstractPolymorphicMessageKey<HummerMessage, FlashImage>(HummerMessage, { it.safeCast() }) {
+        public const val SERIAL_NAME: String = "FlashImage"

        /**
         * 将普通图片转换为闪照.
--- a/mirai-core-api/src/commonMain/kotlin/message/data/Image.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/Image.kt
@ -20,14 +20,10 @@
 package net.mamoe.mirai.message.data

 import kotlinx.serialization.KSerializer
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.builtins.serializer
-import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.descriptors.buildClassSerialDescriptor
-import kotlinx.serialization.encoding.Decoder
-import kotlinx.serialization.encoding.Encoder
-import kotlinx.serialization.encoding.decodeStructure
-import kotlinx.serialization.encoding.encodeStructure
 import net.mamoe.kjbb.JvmBlockingBridge
 import net.mamoe.mirai.Bot
 import net.mamoe.mirai.IMirai
@ -40,6 +36,8 @@ import net.mamoe.mirai.message.data.Image.Key.IMAGE_ID_REGEX
 import net.mamoe.mirai.message.data.Image.Key.IMAGE_RESOURCE_ID_REGEX_1
 import net.mamoe.mirai.message.data.Image.Key.IMAGE_RESOURCE_ID_REGEX_2
 import net.mamoe.mirai.message.data.Image.Key.queryUrl
+import net.mamoe.mirai.message.map
+import net.mamoe.mirai.message.mapPrimitive
 import net.mamoe.mirai.utils.ExternalResource
 import net.mamoe.mirai.utils.ExternalResource.Companion.sendAsImageTo
 import net.mamoe.mirai.utils.ExternalResource.Companion.uploadAsImage
@ -90,26 +88,32 @@ public interface Image : Message, MessageContent, CodableMessage {
     */
    public val imageId: String

-    public object Serializer : KSerializer<Image> {
-        override val descriptor: SerialDescriptor = buildClassSerialDescriptor("net.mamoe.mirai.message.data.Image") {
-            element("imageId", String.serializer().descriptor)
-        }
+    @kotlinx.serialization.Serializer(forClass = Image::class)
+    public object AsStringSerializer : KSerializer<Image> by String.serializer().mapPrimitive(
+        SERIAL_NAME,
+        serialize = { imageId },
+        deserialize = { Image(it) },
+    )

-        override fun deserialize(decoder: Decoder): Image = decoder.decodeStructure(descriptor) {
-            val imageId = if (decodeSequentially()) {
-                decodeStringElement(descriptor, 0)
-            } else {
-                decodeStringElement(descriptor, decodeElementIndex(descriptor))
-            }
-            Image(imageId)
-        }
+    @kotlinx.serialization.Serializer(forClass = Image::class)
+    public object Serializer : KSerializer<Image> by FallbackSerializer("Image")

-        override fun serialize(encoder: Encoder, value: Image): Unit = encoder.encodeStructure(descriptor) {
-            encodeStringElement(descriptor, 0, value.imageId)
-        }
+    @MiraiInternalApi
+    public open class FallbackSerializer(serialName: String) : KSerializer<Image> by Delegate.serializer().map(
+        buildClassSerialDescriptor(serialName) { element("imageId", String.serializer().descriptor) },
+        serialize = { Delegate(imageId) },
+        deserialize = { Image(imageId) },
+    ) {
+        @SerialName(SERIAL_NAME)
+        @Serializable
+        internal data class Delegate(
+            val imageId: String
+        )
    }

    public companion object Key : AbstractMessageKey<Image>({ it.safeCast() }) {
+        public const val SERIAL_NAME: String = "Image"
+
        /**
         * 通过 [Image.imageId] 构造一个 [Image] 以便发送.
         * 这个图片必须是服务器已经存在的图片.
@ -148,8 +152,9 @@ public interface Image : Message, MessageContent, CodableMessage {
        @Suppress("RegExpRedundantEscape") // This is required on Android
        @JvmStatic
        @get:JvmName("getImageIdRegex")
-        public val IMAGE_ID_REGEX: Regex =
-            Regex("""\{[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}\}\..{3,5}""")
+        // inline because compilation error
+        public inline val IMAGE_ID_REGEX: Regex
+            get() = Regex("""\{[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}\}\..{3,5}""")

        /**
         * 图片资源 ID 正则表达式 1. mirai 内部使用.
@ -160,7 +165,9 @@ public interface Image : Message, MessageContent, CodableMessage {
        @JvmStatic
        @MiraiInternalApi
        @get:JvmName("getImageResourceIdRegex1")
-        public val IMAGE_RESOURCE_ID_REGEX_1: Regex = Regex("""/[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}""")
+        // inline because compilation error
+        public inline val IMAGE_RESOURCE_ID_REGEX_1: Regex
+            get() = Regex("""/[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}""")

        /**
         * 图片资源 ID 正则表达式 2. mirai 内部使用.
@ -171,7 +178,9 @@ public interface Image : Message, MessageContent, CodableMessage {
        @JvmStatic
        @MiraiInternalApi
        @get:JvmName("getImageResourceIdRegex2")
-        public val IMAGE_RESOURCE_ID_REGEX_2: Regex = Regex("""/[0-9]*-[0-9]*-[0-9a-fA-F]{32}""")
+        // inline because compilation error
+        public inline val IMAGE_RESOURCE_ID_REGEX_2: Regex
+            get() = Regex("""/[0-9]*-[0-9]*-[0-9a-fA-F]{32}""")
    }
 }

--- a/mirai-core-api/src/commonMain/kotlin/message/data/Message.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/Message.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -20,12 +20,9 @@ package net.mamoe.mirai.message.data
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.fold
 import kotlinx.serialization.*
-import kotlinx.serialization.json.Json
 import net.mamoe.mirai.contact.Contact
 import net.mamoe.mirai.event.events.MessageEvent
 import net.mamoe.mirai.message.MessageReceipt
-import net.mamoe.mirai.message.MessageSerializer
-import net.mamoe.mirai.message.MessageSerializerImpl
 import net.mamoe.mirai.utils.MiraiExperimentalApi
 import net.mamoe.mirai.utils.safeCast
 import kotlin.contracts.contract
@ -73,8 +70,6 @@ import kotlin.internal.LowPriorityInOverloadResolution
 *
 * @see Contact.sendMessage 发送消息
 */
-@Suppress("DEPRECATION_ERROR")
-@Serializable(Message.Serializer::class)
 public interface Message { // must be interface. Don't consider any changes.

    /**
@ -198,50 +193,7 @@ public interface Message { // must be interface. Don't consider any changes.
    public operator fun plus(another: Sequence<Message>): MessageChain =
        another.fold(this, Message::plus).asMessageChain()

-    @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
-    public object Serializer :
-        MessageSerializer by MessageSerializerImpl,
-        KSerializer<Message> by PolymorphicSerializer(Message::class)
-
-    @Suppress("DEPRECATION_ERROR")
-    public companion object {
-        /**
-         * 从 JSON 字符串解析 [Message]
-         * @see serializeToJsonString
-         */
-        @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
-        @JvmOverloads
-        @JvmStatic
-        public fun deserializeFromJsonString(
-            string: String,
-            json: Json = Json { serializersModule = Serializer.serializersModule }
-        ): Message {
-            return json.decodeFromString(Serializer, string)
-        }
-
-        /**
-         * 将 [Message] 序列化为 JSON 字符串.
-         * @see deserializeFromJsonString
-         */
-        @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
-        @JvmOverloads
-        @JvmStatic
-        public fun Message.serializeToJsonString(
-            json: Json = Json { serializersModule = Serializer.serializersModule }
-        ): String = json.encodeToString(Serializer, this)
-
-        /**
-         * 将 [Message] 序列化为指定格式的字符串.
-         *
-         * @see serializeToJsonString
-         * @see StringFormat.encodeToString
-         */
-        @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
-        @ExperimentalSerializationApi
-        @JvmStatic
-        public fun Message.serializeToString(format: StringFormat): String =
-            format.encodeToString(Serializer, this)
-    }
+    public companion object
 }


@ -320,10 +272,11 @@ public inline operator fun Message.times(count: Int): MessageChain = this.repeat
 /**
 * 单个消息元素. 与之相对的是 [MessageChain], 是多个 [SingleMessage] 的集合.
 */
-// @Serializable(SingleMessage.Serializer::class)
+@Serializable(SingleMessage.Serializer::class)
 public interface SingleMessage : Message {
-    // @kotlinx.serialization.Serializer(forClass = SingleMessage::class)
-    //  public object Serializer : KSerializer<SingleMessage> by PolymorphicSerializer(SingleMessage::class)
+    @kotlinx.serialization.Serializer(forClass = SingleMessage::class)
+    public object Serializer :
+        KSerializer<SingleMessage> by PolymorphicSerializer(SingleMessage::class)
 }

 /**
@ -339,14 +292,11 @@ public interface SingleMessage : Message {
 *
 * @see ConstrainSingle 约束一个 [MessageChain] 中只存在这一种类型的元素
 */
-@Serializable(MessageMetadata.Serializer::class)
 public interface MessageMetadata : SingleMessage {
    /**
     * 返回空字符串
     */
    override fun contentToString(): String = ""
-
-    public object Serializer : KSerializer<MessageMetadata> by PolymorphicSerializer(MessageMetadata::class)
 }

 /**
@ -381,11 +331,8 @@ public interface ConstrainSingle : SingleMessage {
 * @see ForwardMessage 合并转发
 * @see Voice 语音
 */
-@Serializable(MessageContent.Serializer::class)
 public interface MessageContent : SingleMessage {
    public companion object Key : AbstractMessageKey<MessageContent>({ it.safeCast() })
-
-    public object Serializer : KSerializer<MessageContent> by PolymorphicSerializer(MessageContent::class)
 }

 /**
--- a/mirai-core-api/src/commonMain/kotlin/message/data/MessageChain.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/MessageChain.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -20,6 +20,7 @@ import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
 import kotlinx.serialization.json.Json
 import net.mamoe.mirai.event.events.MessageEvent
+import net.mamoe.mirai.message.MessageSerializerImpl
 import net.mamoe.mirai.message.code.CodableMessage
 import net.mamoe.mirai.message.data.MessageSource.Key.quote
 import net.mamoe.mirai.message.data.MessageSource.Key.recall
@ -92,9 +93,10 @@ public interface MessageChain : Message, List<SingleMessage>, RandomAccess, Coda
    public operator fun <M : SingleMessage> contains(key: MessageKey<M>): Boolean =
        asSequence().any { key.safeCast.invoke(it) != null }

+    @kotlinx.serialization.Serializer(MessageChain::class)
    public object Serializer : KSerializer<MessageChain> {
        @Suppress("DEPRECATION_ERROR")
-        private val delegate = ListSerializer<Message>(Message.Serializer)
+        private val delegate = ListSerializer(PolymorphicSerializer(SingleMessage::class))
        override val descriptor: SerialDescriptor = delegate.descriptor
        override fun deserialize(decoder: Decoder): MessageChain = delegate.deserialize(decoder).asMessageChain()
        override fun serialize(encoder: Encoder, value: MessageChain): Unit = delegate.serialize(encoder, value)
@ -110,12 +112,11 @@ public interface MessageChain : Message, List<SingleMessage>, RandomAccess, Coda
         * 从 JSON 字符串解析 [MessageChain]
         * @see serializeToJsonString
         */
-        @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
        @JvmOverloads
        @JvmStatic
        public fun deserializeFromJsonString(
            string: String,
-            json: Json = Json { serializersModule = Message.Serializer.serializersModule }
+            json: Json = Json { serializersModule = MessageSerializerImpl.serializersModule }
        ): MessageChain {
            return json.decodeFromString(Serializer, string)
        }
@ -124,12 +125,11 @@ public interface MessageChain : Message, List<SingleMessage>, RandomAccess, Coda
         * 将 [MessageChain] 序列化为 JSON 字符串.
         * @see deserializeFromJsonString
         */
-        @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
        @JvmOverloads
        @JvmStatic
        public fun MessageChain.serializeToJsonString(
-            json: Json = Json { serializersModule = Message.Serializer.serializersModule }
-        ): String = json.encodeToString(Message.Serializer, this)
+            json: Json = Json { serializersModule = MessageSerializerImpl.serializersModule }
+        ): String = json.encodeToString(MessageChain.Serializer, this)

        /**
         * 将 [MessageChain] 序列化为指定格式的字符串.
@ -137,7 +137,6 @@ public interface MessageChain : Message, List<SingleMessage>, RandomAccess, Coda
         * @see serializeToJsonString
         * @see StringFormat.encodeToString
         */
-        @Deprecated("消息序列化仍未稳定，请在 2.0-RC 再使用", level = DeprecationLevel.HIDDEN)
        @ExperimentalSerializationApi
        @JvmStatic
        public fun MessageChain.serializeToString(format: StringFormat): String =
--- a/mirai-core-api/src/commonMain/kotlin/message/data/MessageKey.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/MessageKey.kt
@ -36,7 +36,6 @@ public interface MessageKey<out M : SingleMessage> {
 * @see AbstractPolymorphicMessageKey
 */
 public abstract class AbstractMessageKey<out M : SingleMessage>(
-    @JvmField
    override val safeCast: (SingleMessage) -> M?,
 ) : MessageKey<M>

--- a/mirai-core-api/src/commonMain/kotlin/message/data/MessageSource.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/MessageSource.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -68,7 +68,7 @@ import net.mamoe.mirai.utils.safeCast
 *
 * @see buildMessageSource 构造一个 [OfflineMessageSource]
 */
-@Serializable(MessageSourceSerializerImpl.Companion::class)
+@Serializable(MessageSource.Serializer::class)
 public sealed class MessageSource : Message, MessageMetadata, ConstrainSingle {
    public final override val key: MessageKey<MessageSource>
        get() = Key
@ -150,7 +150,11 @@ public sealed class MessageSource : Message, MessageMetadata, ConstrainSingle {
    public final override fun toString(): String =
        "[mirai:source:${ids.contentToString()},${internalIds.contentToString()}]"

+    public object Serializer : MessageSourceSerializerImpl("MessageSource")
+
    public companion object Key : AbstractMessageKey<MessageSource>({ it.safeCast() }) {
+        public const val SERIAL_NAME: String = "MessageSource"
+
        /**
         * 撤回这条消息. 可撤回自己 2 分钟内发出的消息, 和任意时间的群成员的消息.
         *
@ -361,7 +365,8 @@ public sealed class OnlineMessageSource : MessageSource() {
        }

        public abstract class ToStranger : Outgoing() {
-            public companion object Key : AbstractPolymorphicMessageKey<Outgoing, ToStranger>(Outgoing, { it.safeCast() })
+            public companion object Key :
+                AbstractPolymorphicMessageKey<Outgoing, ToStranger>(Outgoing, { it.safeCast() })

            public abstract override val target: Stranger
            public final override val subject: Stranger get() = target
--- a/mirai-core-api/src/commonMain/kotlin/message/data/PlainText.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/PlainText.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -13,6 +13,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.message.code.CodableMessage
 import net.mamoe.mirai.message.code.internal.appendAsMiraiCode
@ -23,6 +24,7 @@ import net.mamoe.mirai.message.code.internal.appendAsMiraiCode
 * 一般不需要主动构造 [PlainText], [Message] 可直接与 [String] 相加. Java 用户请使用 [Message.plus]
 */
@Serializable
+@SerialName(PlainText.SERIAL_NAME)
 public data class PlainText(
    public val content: String
 ) : MessageContent, CodableMessage {
@ -36,7 +38,9 @@ public data class PlainText(
        builder.appendAsMiraiCode(content)
    }

-    public companion object
+    public companion object {
+        public const val SERIAL_NAME: String = "PlainText"
+    }
 }

 /**
--- a/mirai-core-api/src/commonMain/kotlin/message/data/QuoteReply.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/QuoteReply.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -13,6 +13,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.Bot
 import net.mamoe.mirai.message.data.MessageSource.Key.recall
@ -40,8 +41,13 @@ import net.mamoe.mirai.utils.safeCast
 * @see MessageSource 获取有关消息源的更多信息
 */
@Serializable
-public data class QuoteReply(public val source: MessageSource) : Message, MessageMetadata, ConstrainSingle {
-    public companion object Key : AbstractMessageKey<QuoteReply>({ it.safeCast() })
+@SerialName(QuoteReply.SERIAL_NAME)
+public data class QuoteReply(
+    public val source: MessageSource
+) : Message, MessageMetadata, ConstrainSingle {
+    public companion object Key : AbstractMessageKey<QuoteReply>({ it.safeCast() }) {
+        public const val SERIAL_NAME: String = "QuoteReply"
+    }

    public override val key: MessageKey<QuoteReply> get() = Key

--- a/mirai-core-api/src/commonMain/kotlin/message/data/RichMessage.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/RichMessage.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -13,6 +13,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.message.code.CodableMessage
 import net.mamoe.mirai.message.code.internal.appendAsMiraiCode
@ -95,8 +96,11 @@ public interface RichMessage : MessageContent, ConstrainSingle {
 * @see ServiceMessage 服务消息
 */
@Serializable
+@SerialName(LightApp.SERIAL_NAME)
 public data class LightApp(override val content: String) : RichMessage, CodableMessage {
-    public companion object Key : AbstractMessageKey<LightApp>({ it.safeCast() })
+    public companion object Key : AbstractMessageKey<LightApp>({ it.safeCast() }) {
+        public const val SERIAL_NAME: String = "LightApp"
+    }

    public override fun toString(): String = "[mirai:app:$content]"

@ -117,6 +121,7 @@ public data class LightApp(override val content: String) : RichMessage, CodableM
 */
@MiraiExperimentalApi
@Serializable
+@SerialName(SimpleServiceMessage.SERIAL_NAME)
 public class SimpleServiceMessage(
    public override val serviceId: Int,
    public override val content: String
@ -136,6 +141,9 @@ public class SimpleServiceMessage(
        return result
    }

+    public companion object {
+        public const val SERIAL_NAME: String = "SimpleServiceMessage"
+    }
 }


@ -257,8 +265,7 @@ public class XmlMessageBuilder(
    }
 }

-@Serializable
-@MiraiExperimentalApi
+// internal runtime value, not serializable
 internal data class LongMessage internal constructor(override val content: String, val resId: String) :
    AbstractServiceMessage() {
    override val serviceId: Int get() = 35
@ -266,7 +273,7 @@ internal data class LongMessage internal constructor(override val content: Strin
    companion object Key : AbstractPolymorphicMessageKey<ServiceMessage, LongMessage>(ServiceMessage, { it.safeCast() })
 }

-@Serializable
+// internal runtime value, not serializable
 internal data class ForwardMessageInternal(override val content: String) : AbstractServiceMessage() {
    override val serviceId: Int get() = 35
 }
--- a/mirai-core-api/src/commonMain/kotlin/message/data/Voice.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/Voice.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -9,6 +9,7 @@

 package net.mamoe.mirai.message.data

+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.mamoe.mirai.utils.MiraiExperimentalApi
 import net.mamoe.mirai.utils.MiraiInternalApi
@ -40,6 +41,7 @@ public abstract class PttMessage : MessageContent {
 * 语音消息, 目前只支持接收和转发
 */
@Serializable // experimental
+@SerialName(Voice.SERIAL_NAME)
 public class Voice @MiraiInternalApi constructor(
    @MiraiExperimentalApi public override val fileName: String,
    @MiraiExperimentalApi public override val md5: ByteArray,
@ -49,7 +51,9 @@ public class Voice @MiraiInternalApi constructor(
    private val _url: String
 ) : PttMessage() {

-    public companion object Key : AbstractPolymorphicMessageKey<PttMessage, Voice>(PttMessage, { it.safeCast() })
+    public companion object Key : AbstractPolymorphicMessageKey<PttMessage, Voice>(PttMessage, { it.safeCast() }) {
+        public const val SERIAL_NAME: String = "Voice"
+    }

    public val url: String?
        get() = when {
--- a/mirai-core-api/src/commonMain/kotlin/message/data/impl.kt
+++ b/mirai-core-api/src/commonMain/kotlin/message/data/impl.kt
@ -156,7 +156,7 @@ internal fun <M : SingleMessage> MessageChain.getImpl(key: MessageKey<M>): M? {
 /**
 * 使用 [Collection] 作为委托的 [MessageChain]
 */
-@Serializable
+@Serializable(MessageChain.Serializer::class)
 internal data class MessageChainImpl constructor(
    @JvmField
    internal val delegate: List<SingleMessage> // 必须 constrainSingleMessages, 且为 immutable
--- a/mirai-core/src/commonMain/kotlin/MiraiImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/MiraiImpl.kt
@ -34,6 +34,7 @@ import net.mamoe.mirai.internal.network.protocol.packet.list.FriendList
 import net.mamoe.mirai.internal.network.protocol.packet.login.StatSvc
 import net.mamoe.mirai.internal.utils.io.serialization.toByteArray
 import net.mamoe.mirai.message.MessageReceipt
+import net.mamoe.mirai.message.MessageSerializer
 import net.mamoe.mirai.message.action.Nudge
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.message.data.Image.Key.IMAGE_ID_REGEX
@ -50,17 +51,54 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
    companion object INSTANCE : MiraiImpl() {
        @Suppress("ObjectPropertyName", "unused", "DEPRECATION_ERROR")
        private val _init = Mirai.let {
-            Message.Serializer.registerSerializer(OfflineGroupImage::class, OfflineGroupImage.serializer())
-            Message.Serializer.registerSerializer(OfflineFriendImage::class, OfflineFriendImage.serializer())
-            Message.Serializer.registerSerializer(MarketFaceImpl::class, MarketFaceImpl.serializer())
-            Message.Serializer.registerSerializer(
+            MessageSerializer.registerSerializer(OfflineGroupImage::class, OfflineGroupImage.serializer())
+            MessageSerializer.registerSerializer(OfflineFriendImage::class, OfflineFriendImage.serializer())
+            MessageSerializer.registerSerializer(OnlineFriendImageImpl::class, OnlineFriendImageImpl.serializer())
+            MessageSerializer.registerSerializer(OnlineGroupImageImpl::class, OnlineGroupImageImpl.serializer())
+
+            MessageSerializer.registerSerializer(MarketFaceImpl::class, MarketFaceImpl.serializer())
+
+            // MessageSource
+
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceFromGroupImpl::class,
+                OnlineMessageSourceFromGroupImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceFromFriendImpl::class,
+                OnlineMessageSourceFromFriendImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceFromTempImpl::class,
+                OnlineMessageSourceFromTempImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceFromStrangerImpl::class,
+                OnlineMessageSourceFromStrangerImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceToGroupImpl::class,
+                OnlineMessageSourceToGroupImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceToFriendImpl::class,
+                OnlineMessageSourceToFriendImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceToTempImpl::class,
+                OnlineMessageSourceToTempImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
+                OnlineMessageSourceToStrangerImpl::class,
+                OnlineMessageSourceToStrangerImpl.serializer()
+            )
+            MessageSerializer.registerSerializer(
                OfflineMessageSourceImplData::class,
                OfflineMessageSourceImplData.serializer()
            )
-
-            Message.Serializer.registerSerializer(
-                MessageSourceFromGroupImpl::class,
-                MessageSourceFromGroupImpl.serializer()
+            MessageSerializer.registerSerializer(
+                OfflineMessageSourceImplData::class,
+                OfflineMessageSourceImplData.serializer()
            )
        }
    }
@ -305,12 +343,12 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
        }

        val response: PbMessageSvc.PbMsgWithDraw.Response = when (source) {
-            is MessageSourceToGroupImpl,
-            is MessageSourceFromGroupImpl
+            is OnlineMessageSourceToGroupImpl,
+            is OnlineMessageSourceFromGroupImpl
            -> {
                val group = when (source) {
-                    is MessageSourceToGroupImpl -> source.target
-                    is MessageSourceFromGroupImpl -> source.group
+                    is OnlineMessageSourceToGroupImpl -> source.target
+                    is OnlineMessageSourceFromGroupImpl -> source.group
                    else -> error("stub")
                }
                if (bot.id != source.fromId) {
@ -326,10 +364,10 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
                    ).sendAndExpect<PbMessageSvc.PbMsgWithDraw.Response>()
                }
            }
-            is MessageSourceFromFriendImpl,
-            is MessageSourceToFriendImpl,
-            is MessageSourceFromStrangerImpl,
-            is MessageSourceToStrangerImpl,
+            is OnlineMessageSourceFromFriendImpl,
+            is OnlineMessageSourceToFriendImpl,
+            is OnlineMessageSourceFromStrangerImpl,
+            is OnlineMessageSourceToStrangerImpl,
            -> network.run {
                check(source.fromId == bot.id) {
                    "can only recall a message sent by bot"
@ -342,13 +380,13 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
                    source.time
                ).sendAndExpect<PbMessageSvc.PbMsgWithDraw.Response>()
            }
-            is MessageSourceFromTempImpl,
-            is MessageSourceToTempImpl
+            is OnlineMessageSourceFromTempImpl,
+            is OnlineMessageSourceToTempImpl
            -> network.run {
                check(source.fromId == bot.id) {
                    "can only recall a message sent by bot"
                }
-                source as MessageSourceToTempImpl
+                source as OnlineMessageSourceToTempImpl
                PbMessageSvc.PbMsgWithDraw.createForTempMessage(
                    bot.client,
                    (source.target.group as GroupImpl).uin,
@ -592,7 +630,7 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
        forwardMessage: ForwardMessage?
    ): MessageReceipt<Group> = with(bot.asQQAndroidBot()) {
        message.forEach {
-            it.message.ensureSequenceIdAvailable()
+            it.messageChain.ensureSequenceIdAvailable()
        }

        val group = getGroupOrFail(groupCode)
@ -655,7 +693,7 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
            if (isLong) {
                group.sendMessage(
                    RichMessage.longMessage(
-                        brief = message.joinToString(limit = 27) { it.message.contentToString() },
+                        brief = message.joinToString(limit = 27) { it.messageChain.contentToString() },
                        resId = resId,
                        timeSeconds = time
                    )
--- a/mirai-core/src/commonMain/kotlin/contact/GroupImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/GroupImpl.kt
@ -170,7 +170,7 @@ internal class GroupImpl(
                        ForwardMessage.Node(
                            senderId = bot.id,
                            time = currentTimeSeconds().toInt(),
-                            message = chain,
+                            messageChain = chain,
                            senderName = bot.nick
                        )
                    ),
@ -195,7 +195,7 @@ internal class GroupImpl(
        }

        val result = bot.network.runCatching {
-            val source: MessageSourceToGroupImpl
+            val source: OnlineMessageSourceToGroupImpl
            MessageSvcPbSendMsg.createToGroup(
                bot.client,
                this@GroupImpl,
--- a/mirai-core/src/commonMain/kotlin/contact/NormalMemberImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/NormalMemberImpl.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -19,7 +19,7 @@ import net.mamoe.mirai.contact.*
 import net.mamoe.mirai.data.MemberInfo
 import net.mamoe.mirai.event.broadcast
 import net.mamoe.mirai.event.events.*
-import net.mamoe.mirai.internal.message.MessageSourceToTempImpl
+import net.mamoe.mirai.internal.message.OnlineMessageSourceToTempImpl
 import net.mamoe.mirai.internal.message.ensureSequenceIdAvailable
 import net.mamoe.mirai.internal.message.firstIsInstanceOrNull
 import net.mamoe.mirai.internal.network.protocol.packet.chat.TroopManagement
@ -81,7 +81,7 @@ internal class NormalMemberImpl constructor(
        chain.firstIsInstanceOrNull<QuoteReply>()?.source?.ensureSequenceIdAvailable()

        val result = bot.network.runCatching {
-            val source: MessageSourceToTempImpl
+            val source: OnlineMessageSourceToTempImpl
            MessageSvcPbSendMsg.createToTemp(
                bot.client,
                this@NormalMemberImpl,
--- a/mirai-core/src/commonMain/kotlin/contact/util.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/util.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -16,8 +16,8 @@ import net.mamoe.mirai.contact.*
 import net.mamoe.mirai.event.broadcast
 import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.internal.asQQAndroidBot
-import net.mamoe.mirai.internal.message.MessageSourceToFriendImpl
-import net.mamoe.mirai.internal.message.MessageSourceToStrangerImpl
+import net.mamoe.mirai.internal.message.OnlineMessageSourceToFriendImpl
+import net.mamoe.mirai.internal.message.OnlineMessageSourceToStrangerImpl
 import net.mamoe.mirai.internal.message.ensureSequenceIdAvailable
 import net.mamoe.mirai.internal.network.protocol.packet.chat.receive.MessageSvcPbSendMsg
 import net.mamoe.mirai.internal.network.protocol.packet.chat.receive.createToFriend
@ -37,8 +37,8 @@ internal inline val Bot.uin: Long get() = this.id

 internal suspend fun <T : User> Friend.sendMessageImpl(
    message: Message,
-    friendReceiptConstructor: (MessageSourceToFriendImpl) -> MessageReceipt<Friend>,
-    tReceiptConstructor: (MessageSourceToFriendImpl) -> MessageReceipt<T>
+    friendReceiptConstructor: (OnlineMessageSourceToFriendImpl) -> MessageReceipt<Friend>,
+    tReceiptConstructor: (OnlineMessageSourceToFriendImpl) -> MessageReceipt<T>
 ): MessageReceipt<T> {
    contract { callsInPlace(friendReceiptConstructor, InvocationKind.EXACTLY_ONCE) }
    val bot = bot.asQQAndroidBot()
@ -56,7 +56,7 @@ internal suspend fun <T : User> Friend.sendMessageImpl(

    chain.firstIsInstanceOrNull<QuoteReply>()?.source?.ensureSequenceIdAvailable()

-    lateinit var source: MessageSourceToFriendImpl
+    lateinit var source: OnlineMessageSourceToFriendImpl
    val result = bot.network.runCatching {
        MessageSvcPbSendMsg.createToFriend(
            bot.client,
@ -89,8 +89,8 @@ internal suspend fun <T : User> Friend.sendMessageImpl(

 internal suspend fun <T : User> Stranger.sendMessageImpl(
    message: Message,
-    strangerReceiptConstructor: (MessageSourceToStrangerImpl) -> MessageReceipt<Stranger>,
-    tReceiptConstructor: (MessageSourceToStrangerImpl) -> MessageReceipt<T>
+    strangerReceiptConstructor: (OnlineMessageSourceToStrangerImpl) -> MessageReceipt<Stranger>,
+    tReceiptConstructor: (OnlineMessageSourceToStrangerImpl) -> MessageReceipt<T>
 ): MessageReceipt<T> {
    contract { callsInPlace(strangerReceiptConstructor, InvocationKind.EXACTLY_ONCE) }
    val bot = bot.asQQAndroidBot()
@ -108,7 +108,7 @@ internal suspend fun <T : User> Stranger.sendMessageImpl(

    chain.firstIsInstanceOrNull<QuoteReply>()?.source?.ensureSequenceIdAvailable()

-    lateinit var source: MessageSourceToStrangerImpl
+    lateinit var source: OnlineMessageSourceToStrangerImpl
    val result = bot.network.runCatching {
        MessageSvcPbSendMsg.createToStranger(
            bot.client,
--- a/mirai-core/src/commonMain/kotlin/message/conversions.kt
+++ b/mirai-core/src/commonMain/kotlin/message/conversions.kt
@ -328,13 +328,13 @@ internal fun List<MsgComm.Msg>.toMessageChain(
            checkNotNull(bot) { "bot is null" }

            when (messageSourceKind) {
-                MessageSourceKind.TEMP -> +MessageSourceFromTempImpl(bot, this@toMessageChain)
-                MessageSourceKind.GROUP -> +MessageSourceFromGroupImpl(bot, this@toMessageChain)
-                MessageSourceKind.FRIEND -> +MessageSourceFromFriendImpl(bot, this@toMessageChain)
-                MessageSourceKind.STRANGER -> +MessageSourceFromStrangerImpl(bot, this@toMessageChain)
+                MessageSourceKind.TEMP -> +OnlineMessageSourceFromTempImpl(bot, this@toMessageChain)
+                MessageSourceKind.GROUP -> +OnlineMessageSourceFromGroupImpl(bot, this@toMessageChain)
+                MessageSourceKind.FRIEND -> +OnlineMessageSourceFromFriendImpl(bot, this@toMessageChain)
+                MessageSourceKind.STRANGER -> +OnlineMessageSourceFromStrangerImpl(bot, this@toMessageChain)
            }
        } else {
-            +OfflineMessageSourceImplByMsg(bot, this@toMessageChain, botId)
+            +OfflineMessageSourceImplData(bot, this@toMessageChain, botId)
        }
        elements.joinToMessageChain(groupIdOrZero, botId, this)
        addAll(ptts)
@ -348,7 +348,7 @@ internal fun ImMsgBody.SourceMsg.toMessageChain(botId: Long, groupIdOrZero: Long
    if (elements.isEmpty())
        error("elements for SourceMsg is empty")
    return buildMessageChain(elements.size + 1) {
-        +OfflineMessageSourceImplBySourceMsg(
+        +OfflineMessageSourceImplData(
            delegate = this@toMessageChain,
            botId = botId,
            groupIdOrZero = groupIdOrZero
@ -422,7 +422,7 @@ internal fun List<ImMsgBody.Elem>.joinToMessageChain(groupIdOrZero: Long, botId:
    this.forEach { element ->
        when {
            element.srcMsg != null -> {
-                list.add(QuoteReply(OfflineMessageSourceImplBySourceMsg(element.srcMsg, botId, groupIdOrZero)))
+                list.add(QuoteReply(OfflineMessageSourceImplData(element.srcMsg, botId, groupIdOrZero)))
            }
            element.notOnlineImage != null -> list.add(OnlineFriendImageImpl(element.notOnlineImage))
            element.customFace != null -> list.add(OnlineGroupImageImpl(element.customFace))
--- a/mirai-core/src/commonMain/kotlin/message/faceImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/message/faceImpl.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -10,6 +10,7 @@
 package net.mamoe.mirai.internal.message

 import kotlinx.io.core.toByteArray
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.Transient
 import net.mamoe.mirai.internal.network.protocol.data.proto.HummerCommelem
@ -43,6 +44,7 @@ internal fun Face.toCommData(): ImMsgBody.CommonElem {

 }

+@SerialName(MarketFace.SERIAL_NAME)
@Serializable
 internal data class MarketFaceImpl internal constructor(
    internal val delegate: ImMsgBody.MarketFace,
--- a/mirai-core/src/commonMain/kotlin/message/imagesImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/message/imagesImpl.kt
@ -30,10 +30,13 @@ import net.mamoe.mirai.utils.generateImageIdFromResourceId
 import net.mamoe.mirai.utils.hexToBytes
 import net.mamoe.mirai.utils.toUHexString

+@Serializable(with = OnlineGroupImageImpl.Serializer::class)
 internal class OnlineGroupImageImpl(
    internal val delegate: ImMsgBody.CustomFace
-) : @Suppress("DEPRECATION")
-OnlineGroupImage() {
+) : OnlineGroupImage() {
+    object Serializer : Image.FallbackSerializer("OnlineGroupImage")
+
+
    override val imageId: String = generateImageId(
        delegate.picMd5,
        delegate.filePath.substringAfterLast('.')
@ -58,10 +61,13 @@ OnlineGroupImage() {
    }
 }

+@Serializable(with = OnlineFriendImageImpl.Serializer::class)
 internal class OnlineFriendImageImpl(
    internal val delegate: ImMsgBody.NotOnlineImage
 ) : @Suppress("DEPRECATION")
 OnlineFriendImage() {
+    object Serializer : Image.FallbackSerializer("OnlineFriendImage")
+
    override val imageId: String =
        generateImageIdFromResourceId(delegate.resId, getImageType(delegate.imgType)) ?: delegate.resId
    override val originUrl: String
@ -212,7 +218,6 @@ internal interface SuspendDeferredOriginUrlAware : Image {
    suspend fun getUrl(bot: Bot): String
 }

-@Suppress("EXPOSED_SUPER_INTERFACE")
 internal interface OnlineImage : Image, ConstOriginUrlAware {
    override val originUrl: String
 }
@ -228,11 +233,12 @@ internal interface OfflineImage : Image
 /**
 * @param imageId 参考 [Image.imageId]
 */
-@Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
-@Serializable
+@Serializable(with = OfflineGroupImage.Serializer::class)
 internal data class OfflineGroupImage(
    override val imageId: String
 ) : GroupImage(), OfflineImage, DeferredOriginUrlAware {
+    object Serializer : Image.FallbackSerializer("OfflineGroupImage")
+
    override fun getUrl(bot: Bot): String {
        return "http://gchat.qpic.cn/gchatpic_new/${bot.id}/0-0-${
            imageId.substring(1..36)
@ -265,10 +271,12 @@ internal val Image.friendImageId: String
 *
 * @param imageId 参考 [Image.imageId]
 */
-@Serializable
+@Serializable(with = OfflineFriendImage.Serializer::class)
 internal data class OfflineFriendImage(
    override val imageId: String
 ) : FriendImage(), OfflineImage, DeferredOriginUrlAware {
+    object Serializer : Image.FallbackSerializer("OfflineFriendImage")
+
    override fun getUrl(bot: Bot): String {
        return "http://c2cpicdw.qpic.cn/offpic_new/${bot.id}${this.friendImageId}/0?term=2"
    }
--- a/mirai-core/src/commonMain/kotlin/message/incomingSourceImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/message/incomingSourceImpl.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -71,10 +71,13 @@ internal suspend inline fun Message.ensureSequenceIdAvailable() {
    }*/
 }

-internal class MessageSourceFromFriendImpl(
+@Serializable(OnlineMessageSourceFromFriendImpl.Serializer::class)
+internal class OnlineMessageSourceFromFriendImpl(
    override val bot: Bot,
    val msg: List<MsgComm.Msg>
 ) : OnlineMessageSource.Incoming.FromFriend(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceFromFriend")
+
    override val sequenceIds: IntArray get() = msg.mapToIntArray { it.msgHead.msgSeq }
    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)
    override val ids: IntArray get() = sequenceIds// msg.msgBody.richText.attr!!.random
@ -99,10 +102,13 @@ internal class MessageSourceFromFriendImpl(
    override fun toJceData(): ImMsgBody.SourceMsg = jceData
 }

-internal class MessageSourceFromStrangerImpl(
+@Serializable(OnlineMessageSourceFromStrangerImpl.Serializer::class)
+internal class OnlineMessageSourceFromStrangerImpl(
    override val bot: Bot,
    val msg: List<MsgComm.Msg>
 ) : OnlineMessageSource.Incoming.FromStranger(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceFromStranger")
+
    override val sequenceIds: IntArray get() = msg.mapToIntArray { it.msgHead.msgSeq }
    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)
    override val ids: IntArray get() = sequenceIds// msg.msgBody.richText.attr!!.random
@ -163,10 +169,13 @@ private fun List<MsgComm.Msg>.toJceDataPrivate(ids: IntArray): ImMsgBody.SourceM
    )
 }

-internal class MessageSourceFromTempImpl(
+@Serializable(OnlineMessageSourceFromTempImpl.Serializer::class)
+internal class OnlineMessageSourceFromTempImpl(
    override val bot: Bot,
    private val msg: List<MsgComm.Msg>
 ) : OnlineMessageSource.Incoming.FromTemp(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceFromTemp")
+
    override val sequenceIds: IntArray get() = msg.mapToIntArray { it.msgHead.msgSeq }
    override val internalIds: IntArray get() = msg.mapToIntArray { it.msgBody.richText.attr!!.random }
    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)
@ -190,12 +199,12 @@ internal class MessageSourceFromTempImpl(
    override fun toJceData(): ImMsgBody.SourceMsg = jceData
 }

-@Serializable(MessageSourceFromGroupImpl.Serializer::class)
-internal data class MessageSourceFromGroupImpl(
+@Serializable(OnlineMessageSourceFromGroupImpl.Serializer::class)
+internal data class OnlineMessageSourceFromGroupImpl(
    override val bot: Bot,
    private val msg: List<MsgComm.Msg>
 ) : OnlineMessageSource.Incoming.FromGroup(), MessageSourceInternal {
-    object Serializer : MessageSourceSerializerImpl("net.mamoe.mirai.internal.message.MessageSourceFromGroupImpl")
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceFromGroupImpl")

    @Transient
    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)
--- a/mirai-core/src/commonMain/kotlin/message/offlineSourceImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/message/offlineSourceImpl.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -17,15 +17,15 @@ import net.mamoe.mirai.Bot
 import net.mamoe.mirai.internal.network.protocol.data.proto.ImMsgBody
 import net.mamoe.mirai.internal.network.protocol.data.proto.MsgComm
 import net.mamoe.mirai.internal.network.protocol.data.proto.SourceMsg
-import net.mamoe.mirai.internal.network.protocol.packet.EMPTY_BYTE_ARRAY
 import net.mamoe.mirai.internal.utils.io.serialization.loadAs
+import net.mamoe.mirai.message.MessageSourceSerializerImpl
 import net.mamoe.mirai.message.data.MessageChain
 import net.mamoe.mirai.message.data.MessageSourceKind
 import net.mamoe.mirai.message.data.OfflineMessageSource
 import net.mamoe.mirai.utils.mapToIntArray
 import java.util.concurrent.atomic.AtomicBoolean

-@Serializable
+@Serializable(OfflineMessageSourceImplData.Serializer::class)
 internal data class OfflineMessageSourceImplData(
    override val kind: MessageSourceKind,
    override val ids: IntArray,
@ -36,19 +36,30 @@ internal data class OfflineMessageSourceImplData(
    override val originalMessage: MessageChain,
    override val internalIds: IntArray,
 ) : OfflineMessageSource(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OfflineMessageSource")
+
    override val sequenceIds: IntArray get() = ids

+    // for override.
+    // if provided, no need to serialize from message
+    @Transient
+    var originElems: List<ImMsgBody.Elem>? = null
+
+    // may provided by OfflineMessageSourceImplBySourceMsg
+    @Transient
+    var jceData: ImMsgBody.SourceMsg? = null
+
    @Transient
    @Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)

    override fun toJceData(): ImMsgBody.SourceMsg {
-        return ImMsgBody.SourceMsg(
+        return jceData ?: ImMsgBody.SourceMsg(
            origSeqs = sequenceIds,
            senderUin = fromId,
            toUin = 0,
            flag = 1,
-            elems = originalMessage.toRichTextElems(
+            elems = originElems ?: originalMessage.toRichTextElems(
                null, //forGroup = kind == MessageSourceKind.GROUP,
                withGeneralFlags = false
            ),
@ -56,7 +67,7 @@ internal data class OfflineMessageSourceImplData(
            time = time,
            pbReserve = net.mamoe.mirai.internal.EMPTY_BYTE_ARRAY,
            srcMsg = net.mamoe.mirai.internal.EMPTY_BYTE_ARRAY
-        )
+        ).also { jceData = it }
    }

    override fun equals(other: Any?): Boolean {
@ -90,92 +101,60 @@ internal data class OfflineMessageSourceImplData(
    }
 }

-internal class OfflineMessageSourceImplByMsg(
-    // from other sources' originalMessage
+internal fun OfflineMessageSourceImplData(
    bot: Bot?,
-    val delegate: List<MsgComm.Msg>,
-    override val botId: Long,
-) : OfflineMessageSource(), MessageSourceInternal {
-    override val kind: MessageSourceKind =
-        when {
-            delegate.first().msgHead.groupInfo != null -> {
-                MessageSourceKind.GROUP
-            }
-            delegate.first().msgHead.c2cTmpMsgHead != null -> {
-                MessageSourceKind.TEMP
-            }
-            bot?.getStranger(delegate.first().msgHead.fromUin) != null -> {
-                MessageSourceKind.STRANGER
-            }
-            else -> {
-                MessageSourceKind.FRIEND
-            }
+    delegate: List<MsgComm.Msg>,
+    botId: Long,
+): OfflineMessageSourceImplData {
+    val kind = when {
+        delegate.first().msgHead.groupInfo != null -> {
+            MessageSourceKind.GROUP
        }
-    override val ids: IntArray get() = sequenceIds
-    override val internalIds: IntArray = delegate.mapToIntArray { it.msgHead.msgUid.toInt() }
-    override val time: Int
-        get() = delegate.first().msgHead.msgTime
-    override val fromId: Long
-        get() = delegate.first().msgHead.fromUin
-    override val targetId: Long
-        get() = delegate.first().msgHead.groupInfo?.groupCode ?: delegate.first().msgHead.toUin
-    override val originalMessage: MessageChain by lazy {
-        delegate.toMessageChain(
+        delegate.first().msgHead.c2cTmpMsgHead != null -> {
+            MessageSourceKind.TEMP
+        }
+        bot?.getStranger(delegate.first().msgHead.fromUin) != null -> {
+            MessageSourceKind.STRANGER
+        }
+        else -> {
+            MessageSourceKind.FRIEND
+        }
+    }
+    return OfflineMessageSourceImplData(
+        kind = kind,
+        time = delegate.first().msgHead.msgTime,
+        fromId = delegate.first().msgHead.fromUin,
+        targetId = delegate.first().msgHead.groupInfo?.groupCode ?: delegate.first().msgHead.toUin,
+        originalMessage = delegate.toMessageChain(
            null,
            botId,
            groupIdOrZero = delegate.first().msgHead.groupInfo?.groupCode ?: 0,
            onlineSource = false,
            messageSourceKind = kind
-        )
-    }
-    override val sequenceIds: IntArray = delegate.mapToIntArray { it.msgHead.msgSeq }
-
-    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)
-
-    override fun toJceData(): ImMsgBody.SourceMsg {
-        return ImMsgBody.SourceMsg(
-            origSeqs = delegate.mapToIntArray { it.msgHead.msgSeq },
-            senderUin = delegate.first().msgHead.fromUin,
-            toUin = 0,
-            flag = 1,
-            elems = delegate.flatMap { it.msgBody.richText.elems },
-            type = 0,
-            time = delegate.first().msgHead.msgTime,
-            pbReserve = EMPTY_BYTE_ARRAY,
-            srcMsg = EMPTY_BYTE_ARRAY
-        )
+        ),
+        ids = delegate.mapToIntArray { it.msgHead.msgSeq },
+        internalIds = delegate.mapToIntArray { it.msgHead.msgUid.toInt() },
+        botId = botId
+    ).apply {
+        originElems = delegate.flatMap { it.msgBody.richText.elems }
    }
 }

-internal class OfflineMessageSourceImplBySourceMsg(
-    // from others' quotation
-    val delegate: ImMsgBody.SourceMsg,
-    override val botId: Long,
-    groupIdOrZero: Long
-) : OfflineMessageSource(), MessageSourceInternal {
-    override val kind: MessageSourceKind get() = if (delegate.srcMsg == null) MessageSourceKind.GROUP else MessageSourceKind.FRIEND

-    override var isRecalledOrPlanned: AtomicBoolean = AtomicBoolean(false)
-    override val sequenceIds: IntArray = delegate.origSeqs
-    override val internalIds: IntArray = delegate.pbReserve.loadAs(SourceMsg.ResvAttr.serializer())
-        .origUids?.mapToIntArray { it.toInt() } ?: intArrayOf()
-    override val time: Int get() = delegate.time
-    override val originalMessage: MessageChain by lazy { delegate.toMessageChain(botId, groupIdOrZero) }
-    /*
-    override val ids: Long
-        get() = (delegate.origSeqs?.firstOrNull()
-            ?: error("cannot find sequenceId from ImMsgBody.SourceMsg")).toLong().shl(32) or
-                delegate.pbReserve.loadAs(SourceMsg.ResvAttr.serializer()).origUids!!.and(0xFFFFFFFF)
-    */
-
-    override val ids: IntArray get() = sequenceIds
-    // delegate.pbReserve.loadAs(SourceMsg.ResvAttr.serializer()).origUids?.toInt()
-    // ?: 0
-
-    // override val sourceMessage: MessageChain get() = delegate.toMessageChain()
-    override val fromId: Long get() = delegate.senderUin
-    override val targetId: Long by lazy {
-        when {
+internal fun OfflineMessageSourceImplData(
+    delegate: ImMsgBody.SourceMsg,
+    botId: Long,
+    groupIdOrZero: Long,
+): OfflineMessageSourceImplData {
+    return OfflineMessageSourceImplData(
+        kind = if (delegate.srcMsg == null) MessageSourceKind.GROUP else MessageSourceKind.FRIEND,
+        ids = delegate.origSeqs,
+        internalIds = delegate.pbReserve.loadAs(SourceMsg.ResvAttr.serializer())
+            .origUids?.mapToIntArray { it.toInt() } ?: intArrayOf(),
+        time = delegate.time,
+        originalMessage = delegate.toMessageChain(botId, groupIdOrZero),
+        fromId = delegate.senderUin,
+        targetId = when {
            groupIdOrZero != 0L -> groupIdOrZero
            delegate.toUin != 0L -> delegate.toUin
            delegate.srcMsg != null -> delegate.srcMsg.loadAs(MsgComm.Msg.serializer()).msgHead.toUin
@ -187,10 +166,9 @@ internal class OfflineMessageSourceImplBySourceMsg(
                )
            }"
            )*/
-        }
-    }
-
-    override fun toJceData(): ImMsgBody.SourceMsg {
-        return delegate
+        },
+        botId = botId
+    ).apply {
+        jceData = delegate
    }
 }
--- a/mirai-core/src/commonMain/kotlin/message/outgoingSourceImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/message/outgoingSourceImpl.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -14,6 +14,7 @@ package net.mamoe.mirai.internal.message
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.serialization.Serializable
 import net.mamoe.mirai.Bot
 import net.mamoe.mirai.Mirai
 import net.mamoe.mirai.contact.*
@ -24,6 +25,7 @@ import net.mamoe.mirai.internal.network.protocol.data.proto.SourceMsg
 import net.mamoe.mirai.internal.network.protocol.packet.chat.receive.OnlinePushPbPushGroupMsg.SendGroupMessageReceipt
 import net.mamoe.mirai.internal.network.protocol.packet.chat.toLongUnsigned
 import net.mamoe.mirai.internal.utils.io.serialization.toByteArray
+import net.mamoe.mirai.message.MessageSourceSerializerImpl
 import net.mamoe.mirai.message.data.MessageChain
 import net.mamoe.mirai.message.data.MessageSource
 import net.mamoe.mirai.message.data.OnlineMessageSource
@ -72,7 +74,8 @@ private fun <T> T.toJceDataImpl(subject: ContactOrBot?): ImMsgBody.SourceMsg
    )
 }

-internal class MessageSourceToFriendImpl(
+@Serializable(OnlineMessageSourceToFriendImpl.Serializer::class)
+internal class OnlineMessageSourceToFriendImpl(
    override val sequenceIds: IntArray,
    override val internalIds: IntArray,
    override val time: Int,
@ -80,6 +83,8 @@ internal class MessageSourceToFriendImpl(
    override val sender: Bot,
    override val target: Friend
 ) : OnlineMessageSource.Outgoing.ToFriend(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceToFriend")
+
    override val bot: Bot
        get() = sender
    override val ids: IntArray
@ -89,7 +94,8 @@ internal class MessageSourceToFriendImpl(
    override fun toJceData(): ImMsgBody.SourceMsg = jceData
 }

-internal class MessageSourceToStrangerImpl(
+@Serializable(OnlineMessageSourceToStrangerImpl.Serializer::class)
+internal class OnlineMessageSourceToStrangerImpl(
    override val sequenceIds: IntArray,
    override val internalIds: IntArray,
    override val time: Int,
@ -97,6 +103,8 @@ internal class MessageSourceToStrangerImpl(
    override val sender: Bot,
    override val target: Stranger
 ) : OnlineMessageSource.Outgoing.ToStranger(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceToStranger")
+
    override val bot: Bot
        get() = sender
    override val ids: IntArray
@ -106,7 +114,8 @@ internal class MessageSourceToStrangerImpl(
    override fun toJceData(): ImMsgBody.SourceMsg = jceData
 }

-internal class MessageSourceToTempImpl(
+@Serializable(OnlineMessageSourceToTempImpl.Serializer::class)
+internal class OnlineMessageSourceToTempImpl(
    override val sequenceIds: IntArray,
    override val internalIds: IntArray,
    override val time: Int,
@ -114,6 +123,8 @@ internal class MessageSourceToTempImpl(
    override val sender: Bot,
    override val target: Member
 ) : OnlineMessageSource.Outgoing.ToTemp(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceToTemp")
+
    override val bot: Bot
        get() = sender
    override val ids: IntArray
@ -123,7 +134,8 @@ internal class MessageSourceToTempImpl(
    override fun toJceData(): ImMsgBody.SourceMsg = jceData
 }

-internal class MessageSourceToGroupImpl(
+@Serializable(OnlineMessageSourceToGroupImpl.Serializer::class)
+internal class OnlineMessageSourceToGroupImpl(
    coroutineScope: CoroutineScope,
    override val internalIds: IntArray,
    override val time: Int,
@ -131,6 +143,8 @@ internal class MessageSourceToGroupImpl(
    override val sender: Bot,
    override val target: Group
 ) : OnlineMessageSource.Outgoing.ToGroup(), MessageSourceInternal {
+    object Serializer : MessageSourceSerializerImpl("OnlineMessageSourceToGroup")
+
    override val ids: IntArray
        get() = sequenceIds
    override val bot: Bot
@ -141,7 +155,7 @@ internal class MessageSourceToGroupImpl(
        coroutineScope.asyncFromEventOrNull<SendGroupMessageReceipt, Int>(
            timeoutMillis = 3000
        ) {
-            if (it.messageRandom in this@MessageSourceToGroupImpl.internalIds) {
+            if (it.messageRandom in this@OnlineMessageSourceToGroupImpl.internalIds) {
                it.sequenceId
            } else null
        }
--- a/mirai-core/src/commonMain/kotlin/network/protocol/packet/chat/MultiMsg.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/packet/chat/MultiMsg.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -71,7 +71,7 @@ internal fun Collection<ForwardMessage.INode>.calculateValidationDataForGroup(
            ),
            msgBody = ImMsgBody.MsgBody(
                richText = ImMsgBody.RichText(
-                    elems = chain.message.asMessageChain()
+                    elems = chain.messageChain.asMessageChain()
                        .toRichTextElems(targetGroup, withGeneralFlags = false).toMutableList()
                )
            )
--- a/mirai-core/src/commonMain/kotlin/network/protocol/packet/chat/receive/MessageSvc.PbGetMsg.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/packet/chat/receive/MessageSvc.PbGetMsg.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -17,10 +17,6 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.withLock
-import kotlinx.io.core.ByteReadPacket
-import kotlinx.io.core.discardExact
-import kotlinx.io.core.readUByte
-import kotlinx.io.core.readUShort
 import kotlinx.io.core.*
 import net.mamoe.mirai.Mirai
 import net.mamoe.mirai.contact.Group
@ -34,7 +30,7 @@ import net.mamoe.mirai.event.broadcast
 import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.internal.QQAndroidBot
 import net.mamoe.mirai.internal.contact.*
-import net.mamoe.mirai.internal.message.MessageSourceFromFriendImpl
+import net.mamoe.mirai.internal.message.OnlineMessageSourceFromFriendImpl
 import net.mamoe.mirai.internal.message.toMessageChain
 import net.mamoe.mirai.internal.network.MultiPacket
 import net.mamoe.mirai.internal.network.Packet
@ -437,7 +433,7 @@ internal suspend fun MsgComm.Msg.transform(bot: QQAndroidBot): Packet? {
                            ?: return null// don't compare with dstAppId. diff.

                        val chain = buildMessageChain {
-                            +MessageSourceFromFriendImpl(bot, listOf(this@transform))
+                            +OnlineMessageSourceFromFriendImpl(bot, listOf(this@transform))
                            for (msgItem in textMsg.msgItems) {
                                when (msgItem.type) {
                                    1 -> +PlainText(msgItem.text)
--- a/mirai-core/src/commonMain/kotlin/network/protocol/packet/chat/receive/MessageSvc.PbSendMsg.kt
+++ b/mirai-core/src/commonMain/kotlin/network/protocol/packet/chat/receive/MessageSvc.PbSendMsg.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -143,7 +143,7 @@ internal object MessageSvcPbSendMsg : OutgoingPacketFactory<MessageSvcPbSendMsg.
        client: QQAndroidClient,
        target: Stranger,
        message: MessageChain,
-        source: MessageSourceToStrangerImpl
+        source: OnlineMessageSourceToStrangerImpl
    ): OutgoingPacket = buildOutgoingUniPacket(client) {
        ///writeFully("0A 08 0A 06 08 89 FC A6 8C 0B 12 06 08 01 10 00 18 00 1A 1F 0A 1D 12 08 0A 06 0A 04 F0 9F 92 A9 12 11 AA 02 0E 88 01 00 9A 01 08 78 00 F8 01 00 C8 02 00 20 9B 7A 28 F4 CA 9B B8 03 32 34 08 92 C2 C4 F1 05 10 92 C2 C4 F1 05 18 E6 ED B9 C3 02 20 89 FE BE A4 06 28 89 84 F9 A2 06 48 DE 8C EA E5 0E 58 D9 BD BB A0 09 60 1D 68 92 C2 C4 F1 05 70 00 40 01".hexToBytes())

@ -173,7 +173,7 @@ internal object MessageSvcPbSendMsg : OutgoingPacketFactory<MessageSvcPbSendMsg.
        client: QQAndroidClient,
        targetFriend: Friend,
        message: MessageChain,
-        crossinline sourceCallback: (MessageSourceToFriendImpl) -> Unit
+        crossinline sourceCallback: (OnlineMessageSourceToFriendImpl) -> Unit
    ): List<OutgoingPacket> {
        contract {
            callsInPlace(sourceCallback, InvocationKind.EXACTLY_ONCE)
@ -209,7 +209,7 @@ internal object MessageSvcPbSendMsg : OutgoingPacketFactory<MessageSvcPbSendMsg.
            },
            postInit = {
                sourceCallback(
-                    MessageSourceToFriendImpl(
+                    OnlineMessageSourceToFriendImpl(
                        internalIds = randIds.get(),
                        sender = client.bot,
                        target = targetFriend,
@ -262,7 +262,7 @@ internal object MessageSvcPbSendMsg : OutgoingPacketFactory<MessageSvcPbSendMsg.
        client: QQAndroidClient,
        targetMember: Member,
        message: MessageChain,
-        source: MessageSourceToTempImpl
+        source: OnlineMessageSourceToTempImpl
    ): OutgoingPacket = buildOutgoingUniPacket(client) {
        writeProtoBuf(
            MsgSvc.PbSendMsgReq.serializer(), MsgSvc.PbSendMsgReq(
@ -292,7 +292,7 @@ internal object MessageSvcPbSendMsg : OutgoingPacketFactory<MessageSvcPbSendMsg.
        targetGroup: Group,
        message: MessageChain,
        isForward: Boolean,
-        source: MessageSourceToGroupImpl
+        source: OnlineMessageSourceToGroupImpl
    ): OutgoingPacket = buildOutgoingUniPacket(client) {
        ///writeFully("0A 08 0A 06 08 89 FC A6 8C 0B 12 06 08 01 10 00 18 00 1A 1F 0A 1D 12 08 0A 06 0A 04 F0 9F 92 A9 12 11 AA 02 0E 88 01 00 9A 01 08 78 00 F8 01 00 C8 02 00 20 9B 7A 28 F4 CA 9B B8 03 32 34 08 92 C2 C4 F1 05 10 92 C2 C4 F1 05 18 E6 ED B9 C3 02 20 89 FE BE A4 06 28 89 84 F9 A2 06 48 DE 8C EA E5 0E 58 D9 BD BB A0 09 60 1D 68 92 C2 C4 F1 05 70 00 40 01".hexToBytes())

@ -354,12 +354,12 @@ internal inline fun MessageSvcPbSendMsg.createToTemp(
    client: QQAndroidClient,
    member: Member,
    message: MessageChain,
-    crossinline sourceCallback: (MessageSourceToTempImpl) -> Unit
+    crossinline sourceCallback: (OnlineMessageSourceToTempImpl) -> Unit
 ): OutgoingPacket {
    contract {
        callsInPlace(sourceCallback, InvocationKind.EXACTLY_ONCE)
    }
-    val source = MessageSourceToTempImpl(
+    val source = OnlineMessageSourceToTempImpl(
        internalIds = intArrayOf(Random.nextInt().absoluteValue),
        sender = client.bot,
        target = member,
@ -380,12 +380,12 @@ internal inline fun MessageSvcPbSendMsg.createToStranger(
    client: QQAndroidClient,
    stranger: Stranger,
    message: MessageChain,
-    crossinline sourceCallback: (MessageSourceToStrangerImpl) -> Unit
+    crossinline sourceCallback: (OnlineMessageSourceToStrangerImpl) -> Unit
 ): OutgoingPacket {
    contract {
        callsInPlace(sourceCallback, InvocationKind.EXACTLY_ONCE)
    }
-    val source = MessageSourceToStrangerImpl(
+    val source = OnlineMessageSourceToStrangerImpl(
        internalIds = intArrayOf(Random.nextInt().absoluteValue),
        sender = client.bot,
        target = stranger,
@ -406,7 +406,7 @@ internal inline fun MessageSvcPbSendMsg.createToFriend(
    client: QQAndroidClient,
    qq: Friend,
    message: MessageChain,
-    crossinline sourceCallback: (MessageSourceToFriendImpl) -> Unit
+    crossinline sourceCallback: (OnlineMessageSourceToFriendImpl) -> Unit
 ): List<OutgoingPacket> {
    contract {
        callsInPlace(sourceCallback, InvocationKind.EXACTLY_ONCE)
@ -425,13 +425,13 @@ internal inline fun MessageSvcPbSendMsg.createToGroup(
    group: Group,
    message: MessageChain,
    isForward: Boolean,
-    crossinline sourceCallback: (MessageSourceToGroupImpl) -> Unit
+    crossinline sourceCallback: (OnlineMessageSourceToGroupImpl) -> Unit
 ): OutgoingPacket {
    contract {
        callsInPlace(sourceCallback, InvocationKind.EXACTLY_ONCE)
    }
    val messageRandom = Random.nextInt().absoluteValue
-    val source = MessageSourceToGroupImpl(
+    val source = OnlineMessageSourceToGroupImpl(
        group,
        internalIds = intArrayOf(messageRandom),
        sender = client.bot,
--- a/mirai-core/src/jvmTest/kotlin/message/data/MessageSerializationTest.kt
+++ b/mirai-core/src/jvmTest/kotlin/message/data/MessageSerializationTest.kt
@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 Mamoe Technologies and contributors.
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
 *
 *  此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
 *  Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
@ -15,6 +15,7 @@ import kotlinx.serialization.serializer
 import net.mamoe.mirai.Mirai
 import net.mamoe.mirai.internal.message.MarketFaceImpl
 import net.mamoe.mirai.internal.network.protocol.data.proto.ImMsgBody
+import net.mamoe.mirai.message.MessageSerializer
 import net.mamoe.mirai.message.data.*
 import org.junit.jupiter.api.BeforeAll
 import org.junit.jupiter.api.Test
@ -22,11 +23,13 @@ import kotlin.test.assertEquals

 internal class MessageSerializationTest {
    @Suppress("DEPRECATION_ERROR")
-    private val module get() = Message.Serializer.serializersModule
+    private val module
+        get() = MessageSerializer.serializersModule
    private val format
        get() = Json {
            serializersModule = module
            useArrayPolymorphism = false // ?
+            ignoreUnknownKeys = true
        }

    private inline fun <reified T : Any> T.serialize(serializer: KSerializer<T> = module.serializer()): String {
@ -38,7 +41,14 @@ internal class MessageSerializationTest {
    }

    private inline fun <reified T : Any> testSerialization(t: T, serializer: KSerializer<T> = module.serializer()) {
-        val deserialized = t.serialize(serializer).deserialize(serializer)
+        val deserialized = kotlin.runCatching {
+            println("Testing ${t::class.simpleName} with serializer $serializer")
+            val serialized = t.serialize(serializer)
+            println("Result: ${serializer.descriptor.serialName}  $serialized")
+            serialized.deserialize(serializer)
+        }.getOrElse {
+            throw AssertionError("Failed to serialize $t", it)
+        }
        assertEquals(
            t,
            deserialized,
@ -78,7 +88,6 @@ internal class MessageSerializationTest {

    @Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
    private val testConstrainSingleMessageInstances: Array<out ConstrainSingle> = arrayOf(
-        LongMessage("content", "resId"),
        Mirai.constructMessageSource(
            1L,
            MessageSourceKind.FRIEND,
@ -100,7 +109,12 @@ internal class MessageSerializationTest {
    }

    @Test
-    fun `test serialize each message contents`() {
+    fun `test polymorphic serialization`() {
+
+    }
+
+    @Test
+    fun `test contextual serialization`() {
        for (message in testMessageContentInstances) {
            testSerialization(message, module.serializer(message.javaClass))
        }