Don't send group update on PNI decline

ts/groups.ts

@@ -1455,6 +1455,7 @@ export async function modifyGroupV2({
   extraConversationsForSend,
   inviteLinkPassword,
   name,
+  syncMessageOnly = false,
 }: {
   conversation: ConversationModel;
   usingCredentialsFrom: ReadonlyArray<ConversationModel>;
@@ -1462,6 +1463,7 @@ export async function modifyGroupV2({
   extraConversationsForSend?: ReadonlyArray<string>;
   inviteLinkPassword?: string;
   name: string;
+  syncMessageOnly?: boolean;
 }): Promise<void> {
   const logId = `${name}/${conversation.idForLogging()}`;
 
@@ -1561,7 +1563,7 @@ export async function modifyGroupV2({
           type: conversationQueueJobEnum.enum.GroupUpdate,
           conversationId: conversation.id,
           groupChangeBase64,
-          recipients: groupV2Info.members.slice(),
+          recipients: syncMessageOnly ? [] : groupV2Info.members.slice(),
           revision: groupV2Info.revision,
         });
       });

ts/models/conversations.ts

@@ -755,12 +755,14 @@ export class ConversationModel extends window.Backbone
     extraConversationsForSend,
     inviteLinkPassword,
     name,
+    syncMessageOnly,
   }: {
     usingCredentialsFrom: ReadonlyArray<ConversationModel>;
     createGroupChange: () => Promise<Proto.GroupChange.Actions | undefined>;
     extraConversationsForSend?: ReadonlyArray<string>;
     inviteLinkPassword?: string;
     name: string;
+    syncMessageOnly?: boolean;
   }): Promise<void> {
     await window.Signal.Groups.modifyGroupV2({
       conversation: this,
@@ -769,6 +771,7 @@ export class ConversationModel extends window.Backbone
       extraConversationsForSend,
       inviteLinkPassword,
       name,
+      syncMessageOnly,
     });
   }
 
@@ -2597,6 +2600,7 @@ export class ConversationModel extends window.Backbone
         name: 'delete',
         usingCredentialsFrom: [],
         createGroupChange: () => this.removePendingMember([ourPNI]),
+        syncMessageOnly: true,
       });
     } else {
       const logId = this.idForLogging();

ts/test-mock/pnp/accept_gv2_invite_test.ts

@@ -3,7 +3,7 @@
 
 import { assert } from 'chai';
 import type { Group } from '@signalapp/mock-server';
-import { UUIDKind } from '@signalapp/mock-server';
+import { Proto, UUIDKind } from '@signalapp/mock-server';
 import createDebug from 'debug';
 
 import * as durations from '../../util/durations';
@@ -159,6 +159,21 @@ describe('pnp/accept gv2 invite', function needsName() {
     assert(!group.getMemberByUUID(desktop.pni));
     assert(!group.getPendingMemberByUUID(desktop.uuid));
     assert(!group.getPendingMemberByUUID(desktop.pni));
+
+    // Verify that sync message was sent.
+    const { syncMessage } = await phone.waitForSyncMessage(entry =>
+      Boolean(entry.syncMessage.sent?.message?.groupV2?.groupChange)
+    );
+    const groupChangeBuffer = syncMessage.sent?.message?.groupV2?.groupChange;
+    assert.notEqual(groupChangeBuffer, null);
+    const groupChange = Proto.GroupChange.decode(
+      groupChangeBuffer ?? new Uint8Array(0)
+    );
+    assert.notEqual(groupChange.actions, null);
+    const actions = Proto.GroupChange.Actions.decode(
+      groupChange?.actions ?? new Uint8Array(0)
+    );
+    assert.strictEqual(actions.deletePendingMembers.length, 1);
   });
 
   it('should accept ACI invite with extra PNI on the invite list', async () => {