feat(onebot): add group_name to group message events (#212)

Group message events (message + message_sent) now carry group_name — a
non-standard but common OneBot extension. The name comes from the
message's own wire field (ResponseGrp field 7, accurate even right after
a rename), falling back to the identity group cache, else '' when neither
is available. It's resolved in the group-message decoder, where both the
wire head and the identity cache are already at hand, so the converter
just passes it through (no ConverterContext change).

Verified live (tempserver): real inbound group messages from a non-self
account carry group_name set to the actual group name.

packages/onebot/src/event-converter/to-message.ts

@@ -73,6 +73,7 @@ export async function convertGroupMessage(ctx: ConverterContext, event: GroupMes
     message_id: messageId,
     message_seq: event.msgSeq,
     group_id: event.groupId,
+    group_name: event.groupName,
     user_id: event.senderUin,
     message: segments,
     raw_message: segmentsToRawMessage(segments),

packages/onebot/tests/event-converter.test.ts

@@ -54,6 +54,7 @@ function makeGroupMessage(senderUin: number): GroupMessage {
     time: 1700000000,
     selfUin: SELF_ID,
     groupId: 99999,
+    groupName: 'Test Group 测试群',
     senderUin,
     senderNick: senderUin === SELF_ID ? 'me' : 'peer',
     senderCard: '',
@@ -100,6 +101,7 @@ describe('convertEvent — message kinds', () => {
     expect(out!.message_type).toBe('group');
     expect(out!.sub_type).toBe('normal');
     expect(out!.group_id).toBe(GROUP_ID);
+    expect(out!.group_name).toBe('Test Group 测试群');
   });
 
   it('group_message self → post_type "message_sent"', async () => {

packages/protocol/src/events.ts

@@ -133,6 +133,10 @@ export interface FriendMessage extends QQEvent {
 export interface GroupMessage extends QQEvent {
   kind: 'group_message';
   groupId: number;
+  /** Group display name. From the message's own wire field (ResponseGrp
+   *  field 7 — accurate even right after a rename), falling back to the
+   *  identity group cache, else '' when neither is available. */
+  groupName: string;
   senderUin: number;
   senderNick: string;
   senderCard: string;

packages/protocol/src/msg-push/decoders/group-message.ts

@@ -12,6 +12,7 @@ export const decodeGroupMessage: MsgPushDecoder = (ctx) => {
     msgId: ctx.head.msgId & 0x7FFFFFFF,
     elements: decodeRichBody(ctx.body, true),
     groupId: 0,
+    groupName: '',
     senderNick: '',
     senderCard: '',
     senderRole: '',
@@ -43,5 +44,9 @@ export const decodeGroupMessage: MsgPushDecoder = (ctx) => {
   } else if (!ev.senderNick && grp?.memberCard) {
     ev.senderNick = grp.memberCard;
   }
+  // Group name: prefer the message's own wire field (ResponseGrp field 7 —
+  // fresh even right after a rename), fall back to the cached group list, else
+  // leave it empty. `ev.groupId` is set above from grp.groupUin.
+  ev.groupName = grp?.groupName || ctx.identity.findGroup(ev.groupId)?.groupName || '';
   return [ev];
 };

packages/protocol/tests/msg-push/fetch-group-history.test.ts

@@ -9,7 +9,7 @@ import type { SsoGetGroupMsg, SsoGetGroupMsgResponse } from '@snowluma/proto-def
 import type { IdentityService } from '../../src/identity-service';
 import { SSO_GET_GROUP_MSG_CMD, fetchGroupMessageRange } from '../../src/msg-push';
 
-const identity = { findGroupMember: () => undefined } as unknown as IdentityService;
+const identity = { findGroupMember: () => undefined, findGroup: () => null } as unknown as IdentityService;
 
 function okResult(data: Uint8Array): SendPacketResult {
   return { success: true, gotResponse: true, responseData: data } as SendPacketResult;
@@ -69,7 +69,7 @@ describe('fetchGroupMessageRange / SsoGetGroupMsg', () => {
 
   it('[#1] prefers the fresher group card in grp.memberCard (field 4) over a stale cache card', async () => {
     const stale = { uin: 222, uid: '', nickname: 'BaseNick', card: 'StaleCard', role: 'member', level: 0, title: '', joinTime: 0, lastSentTime: 0, shutUpTime: 0 };
-    const idWithMember = { findGroupMember: (_g: number, u: number) => (u === 222 ? stale : undefined) } as unknown as IdentityService;
+    const idWithMember = { findGroupMember: (_g: number, u: number) => (u === 222 ? stale : undefined), findGroup: () => null } as unknown as IdentityService;
     const resp = protobuf_encode<SsoGetGroupMsgResponse>({
       body: { groupUin: 9999, messages: [
         { responseHead: { fromUin: 222, grp: { groupUin: 9999, memberCard: 'FreshCard' } }, // field2 empty, field4 = fresh card
@@ -84,7 +84,7 @@ describe('fetchGroupMessageRange / SsoGetGroupMsg', () => {
 
   it('[#1] keeps the cache card when field 4 equals the base nickname (no active group card)', async () => {
     const m = { uin: 222, uid: '', nickname: 'BaseNick', card: 'CachedCard', role: 'member', level: 0, title: '', joinTime: 0, lastSentTime: 0, shutUpTime: 0 };
-    const id = { findGroupMember: () => m } as unknown as IdentityService;
+    const id = { findGroupMember: () => m, findGroup: () => null } as unknown as IdentityService;
     const resp = protobuf_encode<SsoGetGroupMsgResponse>({
       body: { groupUin: 9999, messages: [
         { responseHead: { fromUin: 222, grp: { groupUin: 9999, memberCard: 'BaseNick' } }, // field4 == base nick → not a card