diff --git a/mirai-core/src/commonMain/kotlin/network/notice/NewContactSupport.kt b/mirai-core/src/commonMain/kotlin/network/notice/NewContactSupport.kt
index beb8f66bd..c8f86c23d 100644
--- a/mirai-core/src/commonMain/kotlin/network/notice/NewContactSupport.kt
+++ b/mirai-core/src/commonMain/kotlin/network/notice/NewContactSupport.kt
@@ -47,9 +47,10 @@ internal interface NewContactSupport { // can be a marker interface when context
         return getNewGroup(code)?.apply { groups.delegate.add(this) }
     }
 
+    // final
     suspend fun QQAndroidBot.addNewGroupByUin(groupUin: Long): GroupImpl? {
         if (getGroupByUin(groupUin) != null) return null
-        return getNewGroup(Mirai.calculateGroupCodeByGroupUin(groupUin))?.apply { groups.delegate.add(this) }
+        return addNewGroupByCode(Mirai.calculateGroupCodeByGroupUin(groupUin))
     }
 
     suspend fun QQAndroidBot.addNewGroup(stTroopNum: StTroopNum): GroupImpl? {
diff --git a/mirai-core/src/commonMain/kotlin/network/notice/group/GroupOrMemberListNoticeProcessor.kt b/mirai-core/src/commonMain/kotlin/network/notice/group/GroupOrMemberListNoticeProcessor.kt
index cdaa41037..203845cd7 100644
--- a/mirai-core/src/commonMain/kotlin/network/notice/group/GroupOrMemberListNoticeProcessor.kt
+++ b/mirai-core/src/commonMain/kotlin/network/notice/group/GroupOrMemberListNoticeProcessor.kt
@@ -20,6 +20,7 @@ import net.mamoe.mirai.contact.MemberPermission.*
 import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.internal.contact.addNewNormalMember
 import net.mamoe.mirai.internal.contact.info.MemberInfoImpl
+import net.mamoe.mirai.internal.getGroupByCodeOrUin
 import net.mamoe.mirai.internal.getGroupByUin
 import net.mamoe.mirai.internal.getGroupByUinOrCode
 import net.mamoe.mirai.internal.message.contextualBugReportException
@@ -136,14 +137,14 @@ internal class GroupOrMemberListNoticeProcessor(
     // 33
     private suspend fun NoticePipelineContext.processGroupJoin33(data: MsgComm.Msg) = data.context {
         msgBody.msgContent.read {
-            val groupUin = Mirai.calculateGroupUinByGroupCode(readUInt().toLong())
+            val groupCode = readUInt().toLong()
             if (remaining < 5) return
             discardExact(1)
             val joinedMemberUin = readUInt().toLong()
 
-            if (joinedMemberUin == bot.id && bot.getGroupByUin(groupUin) != null) return // duplicate
+            if (joinedMemberUin == bot.id && bot.getGroupByCodeOrUin(groupCode) != null) return // duplicate
 
-            val group = bot.getGroupByUin(groupUin) ?: bot.addNewGroupByUin(groupUin) ?: return
+            val group = bot.getGroupByCodeOrUin(groupCode) ?: bot.addNewGroupByCode(groupCode) ?: return
             val joinType = readByte().toInt()
             val invitorUin = readUInt().toLong()
             when (joinType) {
diff --git a/mirai-core/src/commonTest/kotlin/notice/processors/BotInvitedJoinTest.kt b/mirai-core/src/commonTest/kotlin/notice/processors/BotInvitedJoinTest.kt
index 867b03448..c27531cd3 100644
--- a/mirai-core/src/commonTest/kotlin/notice/processors/BotInvitedJoinTest.kt
+++ b/mirai-core/src/commonTest/kotlin/notice/processors/BotInvitedJoinTest.kt
@@ -106,8 +106,8 @@ internal class BotInvitedJoinTest : AbstractNoticeProcessorTest() {
         suspend fun runTest() = use(
             createContext = { bot, attributes ->
                 object : NoticeProcessorPipelineImpl.ContextImpl(bot, attributes) {
-                    override suspend fun QQAndroidBot.addNewGroupByUin(groupUin: Long): GroupImpl {
-                        assertEquals(204230203, groupUin) // uin of 2230203
+                    override suspend fun QQAndroidBot.addNewGroupByCode(code: Long): GroupImpl {
+                        assertEquals(2230203, code)
                         return bot.addGroup(2230203, 1230001, name = "testtest").apply {
                             addMember(1230003, permission = MemberPermission.MEMBER)
                             addMember(1230001, permission = MemberPermission.OWNER)
@@ -156,8 +156,8 @@ internal class BotInvitedJoinTest : AbstractNoticeProcessorTest() {
         suspend fun runTest() =
             use(createContext = { bot, attributes ->
                 object : NoticeProcessorPipelineImpl.ContextImpl(bot, attributes) {
-                    override suspend fun QQAndroidBot.addNewGroupByUin(groupUin: Long): GroupImpl {
-                        assertEquals(204230203, groupUin) // uin of 2230203
+                    override suspend fun QQAndroidBot.addNewGroupByCode(code: Long): GroupImpl {
+                        assertEquals(2230203, code)
                         return bot.addGroup(2230203, 1230002, name = "testtest").apply {
                             addMember(1230001, permission = MemberPermission.MEMBER)
                         }