Show Session Switchover Events

Co-authored-by: Scott Nonnenberg <scott@signal.org>

_locales/en/messages.json

@@ -1489,6 +1489,14 @@
     "messageformat": "Your message history for both chats have been merged here.",
     "description": "Contents of a dialog shown after clicking 'learn more' button on a conversation merge event."
   },
+  "icu:PhoneNumberDiscovery--notification--withSharedGroup": {
+    "messageformat": "{phoneNumber} belongs to {conversationTitle}. You're both members of {sharedGroup}.",
+    "description": "Shown when we've discovered a phone number for a contact you've been communicating with."
+  },
+  "icu:PhoneNumberDiscovery--notification--noSharedGroup": {
+    "messageformat": "{phoneNumber} belongs to {conversationTitle}",
+    "description": "Shown when we've discovered a phone number for a contact you've been communicating with, but you have no shared groups."
+  },
   "icu:quoteThumbnailAlt": {
     "messageformat": "Thumbnail of image from quoted message",
     "description": "Used in alt tag of thumbnail images inside of an embedded message quote"

ts/ConversationController.ts

@@ -471,7 +471,7 @@ export class ConversationController {
     e164,
     pni: providedPni,
     reason,
-    fromPniSignature,
+    fromPniSignature = false,
     mergeOldAndNew = safeCombineConversations,
   }: {
     aci?: AciString;
@@ -526,6 +526,12 @@ export class ConversationController {
     let unusedMatches: Array<ConvoMatchType> = [];
 
     let targetConversation: ConversationModel | undefined;
+    let targetOldServiceIds:
+      | {
+          aci?: AciString;
+          pni?: PniString;
+        }
+      | undefined;
     let matchCount = 0;
     matches.forEach(item => {
       const { key, value, match } = item;
@@ -597,6 +603,11 @@ export class ConversationController {
           );
         }
 
+        targetOldServiceIds = {
+          aci: targetConversation.getAci(),
+          pni: targetConversation.getPni(),
+        };
+
         log.info(
           `${logId}: Applying new value for ${unused.key} to target conversation`
         );
@@ -686,9 +697,32 @@ export class ConversationController {
         //   `${logId}: Match on ${key} is target conversation - ${match.idForLogging()}`
         // );
         targetConversation = match;
+        targetOldServiceIds = {
+          aci: targetConversation.getAci(),
+          pni: targetConversation.getPni(),
+        };
       }
     });
 
+    // If the change is not coming from PNI Signature, and target conversation
+    // had PNI and has acquired new ACI and/or PNI we should check if it had
+    // a PNI session on the original PNI. If yes - add a PhoneNumberDiscovery notification
+    if (
+      e164 &&
+      pni &&
+      targetConversation &&
+      targetOldServiceIds?.pni &&
+      !fromPniSignature &&
+      (targetOldServiceIds.pni !== pni ||
+        (aci && targetOldServiceIds.aci !== aci))
+    ) {
+      mergePromises.push(
+        targetConversation.addPhoneNumberDiscoveryIfNeeded(
+          targetOldServiceIds.pni
+        )
+      );
+    }
+
     if (targetConversation) {
       return { conversation: targetConversation, mergePromises };
     }

ts/SignalProtocolStore.ts

@@ -1467,6 +1467,18 @@ export class SignalProtocolStore extends EventEmitter {
     });
   }
 
+  async hasSessionWith(serviceId: ServiceIdString): Promise<boolean> {
+    return this.withZone(GLOBAL_ZONE, 'hasSessionWith', async () => {
+      if (!this.sessions) {
+        throw new Error('getOpenDevices: this.sessions not yet cached!');
+      }
+
+      return this._getAllSessions().some(
+        ({ fromDB }) => fromDB.serviceId === serviceId
+      );
+    });
+  }
+
   async getOpenDevices(
     ourServiceId: ServiceIdString,
     serviceIds: ReadonlyArray<ServiceIdString>,

ts/components/conversation/PhoneNumberDiscoveryNotification.stories.tsx

@@ -0,0 +1,34 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import * as React from 'react';
+import type { Meta } from '@storybook/react';
+import { setupI18n } from '../../util/setupI18n';
+import enMessages from '../../../_locales/en/messages.json';
+import type { PropsType } from './PhoneNumberDiscoveryNotification';
+import { PhoneNumberDiscoveryNotification } from './PhoneNumberDiscoveryNotification';
+
+const i18n = setupI18n('en', enMessages);
+
+export default {
+  title: 'Components/Conversation/PhoneNumberDiscoveryNotification',
+} satisfies Meta<PropsType>;
+
+const createProps = (overrideProps: Partial<PropsType> = {}): PropsType => ({
+  i18n,
+  conversationTitle: overrideProps.conversationTitle || 'John Fire',
+  phoneNumber: '(555) 333-1111',
+});
+
+export function WithoutSharedGroup(): JSX.Element {
+  return <PhoneNumberDiscoveryNotification {...createProps()} />;
+}
+
+export function WithSharedGroup(): JSX.Element {
+  return (
+    <PhoneNumberDiscoveryNotification
+      {...createProps()}
+      sharedGroup="Fun Times"
+    />
+  );
+}

ts/components/conversation/PhoneNumberDiscoveryNotification.tsx

@@ -0,0 +1,34 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import React from 'react';
+
+import type { LocalizerType } from '../../types/Util';
+import { SystemMessage } from './SystemMessage';
+import { Emojify } from './Emojify';
+import { getStringForPhoneNumberDiscovery } from '../../util/getStringForPhoneNumberDiscovery';
+
+export type PropsDataType = {
+  conversationTitle: string;
+  phoneNumber: string;
+  sharedGroup?: string;
+};
+export type PropsType = PropsDataType & {
+  i18n: LocalizerType;
+};
+
+// Also known as a Session Switchover Event (SSE)
+export function PhoneNumberDiscoveryNotification(
+  props: PropsType
+): JSX.Element {
+  const { conversationTitle, i18n, sharedGroup, phoneNumber } = props;
+
+  const message = getStringForPhoneNumberDiscovery({
+    conversationTitle,
+    i18n,
+    phoneNumber,
+    sharedGroup,
+  });
+
+  return <SystemMessage icon="info" contents={<Emojify text={message} />} />;
+}

ts/components/conversation/TimelineItem.tsx

@@ -50,6 +50,8 @@ import type { PropsType as PaymentEventNotificationPropsType } from './PaymentEv
 import { PaymentEventNotification } from './PaymentEventNotification';
 import type { PropsDataType as ConversationMergeNotificationPropsType } from './ConversationMergeNotification';
 import { ConversationMergeNotification } from './ConversationMergeNotification';
+import type { PropsDataType as PhoneNumberDiscoveryNotificationPropsType } from './PhoneNumberDiscoveryNotification';
+import { PhoneNumberDiscoveryNotification } from './PhoneNumberDiscoveryNotification';
 import { SystemMessage } from './SystemMessage';
 import type { FullJSXType } from '../Intl';
 import { TimelineMessage } from './TimelineMessage';
@@ -122,6 +124,10 @@ type ConversationMergeNotificationType = {
   type: 'conversationMerge';
   data: ConversationMergeNotificationPropsType;
 };
+type PhoneNumberDiscoveryNotificationType = {
+  type: 'phoneNumberDiscovery';
+  data: PhoneNumberDiscoveryNotificationPropsType;
+};
 type PaymentEventType = {
   type: 'paymentEvent';
   data: Omit<PaymentEventNotificationPropsType, 'i18n'>;
@@ -137,6 +143,7 @@ export type TimelineItemType = (
   | GroupV1MigrationType
   | GroupV2ChangeType
   | MessageType
+  | PhoneNumberDiscoveryNotificationType
   | ProfileChangeNotificationType
   | ResetSessionNotificationType
   | SafetyNumberNotificationType
@@ -330,6 +337,14 @@ export const TimelineItem = memo(function TimelineItem({
           i18n={i18n}
         />
       );
+    } else if (item.type === 'phoneNumberDiscovery') {
+      notification = (
+        <PhoneNumberDiscoveryNotification
+          {...reducedProps}
+          {...item.data}
+          i18n={i18n}
+        />
+      );
     } else if (item.type === 'resetSessionNotification') {
       notification = <ResetSessionNotification {...reducedProps} i18n={i18n} />;
     } else if (item.type === 'profileChange') {

ts/model-types.d.ts

@@ -181,6 +181,7 @@ export type MessageAttributesType = {
     | 'incoming'
     | 'keychange'
     | 'outgoing'
+    | 'phone-number-discovery'
     | 'profile-change'
     | 'story'
     | 'timer-notification'
@@ -214,6 +215,9 @@ export type MessageAttributesType = {
     source?: string;
     sourceServiceId?: ServiceIdString;
   };
+  phoneNumberDiscovery?: {
+    e164: string;
+  };
   conversationMerge?: {
     renderInfo: ConversationRenderInfoType;
   };

ts/models/conversations.ts

@@ -3032,6 +3032,59 @@ export class ConversationModel extends window.Backbone
     this.trigger('newmessage', model);
   }
 
+  async addPhoneNumberDiscoveryIfNeeded(originalPni: PniString): Promise<void> {
+    const logId = `addPhoneNumberDiscoveryIfNeeded(${this.idForLogging()}, ${originalPni})`;
+
+    const e164 = this.get('e164');
+
+    if (!e164) {
+      log.info(`${logId}: not adding, no e164`);
+      return;
+    }
+
+    const hadSession = await window.textsecure.storage.protocol.hasSessionWith(
+      originalPni
+    );
+
+    if (!hadSession) {
+      log.info(`${logId}: not adding, no PNI session`);
+      return;
+    }
+
+    log.info(`${logId}: adding notification`);
+    const timestamp = Date.now();
+    const message: MessageAttributesType = {
+      id: generateGuid(),
+      conversationId: this.id,
+      type: 'phone-number-discovery',
+      sent_at: timestamp,
+      timestamp,
+      received_at: incrementMessageCounter(),
+      received_at_ms: timestamp,
+      phoneNumberDiscovery: {
+        e164,
+      },
+      readStatus: ReadStatus.Read,
+      seenStatus: SeenStatus.Unseen,
+      schemaVersion: Message.VERSION_NEEDED_FOR_DISPLAY,
+    };
+
+    const id = await window.Signal.Data.saveMessage(message, {
+      ourAci: window.textsecure.storage.user.getCheckedAci(),
+      forceSave: true,
+    });
+    const model = window.MessageCache.__DEPRECATED$register(
+      id,
+      new window.Whisper.Message({
+        ...message,
+        id,
+      }),
+      'addPhoneNumberDiscoveryIfNeeded'
+    );
+
+    this.trigger('newmessage', model);
+  }
+
   async addVerifiedChange(
     verifiedChangeId: string,
     verified: boolean,

ts/models/messages.ts

@@ -98,6 +98,7 @@ import {
   isUnsupportedMessage,
   isVerifiedChange,
   isConversationMerge,
+  isPhoneNumberDiscovery,
 } from '../state/selectors/message';
 import type { ReactionAttributesType } from '../messageModifiers/Reactions';
 import { isInCall } from '../state/selectors/calling';
@@ -139,6 +140,7 @@ import { SeenStatus } from '../MessageSeenStatus';
 import { isNewReactionReplacingPrevious } from '../reactions/util';
 import { parseBoostBadgeListFromServer } from '../badges/parseBadgesFromServer';
 import type { StickerWithHydratedData } from '../types/Stickers';
+
 import {
   addToAttachmentDownloadQueue,
   shouldUseAttachmentDownloadQueue,
@@ -313,6 +315,7 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
       !isGroupV1Migration(attributes) &&
       !isGroupV2Change(attributes) &&
       !isKeyChange(attributes) &&
+      !isPhoneNumberDiscovery(attributes) &&
       !isProfileChange(attributes) &&
       !isUniversalTimerNotification(attributes) &&
       !isUnsupportedMessage(attributes) &&
@@ -643,6 +646,7 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
     const isUniversalTimerNotificationValue =
       isUniversalTimerNotification(attributes);
     const isConversationMergeValue = isConversationMerge(attributes);
+    const isPhoneNumberDiscoveryValue = isPhoneNumberDiscovery(attributes);
 
     const isPayment = messageHasPaymentEvent(attributes);
 
@@ -674,7 +678,8 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
       isKeyChangeValue ||
       isProfileChangeValue ||
       isUniversalTimerNotificationValue ||
-      isConversationMergeValue;
+      isConversationMergeValue ||
+      isPhoneNumberDiscoveryValue;
 
     return !hasSomethingToDisplay;
   }

ts/state/selectors/message.ts

@@ -34,6 +34,7 @@ import type { PropsDataType as GroupV1MigrationPropsType } from '../../component
 import type { PropsDataType as DeliveryIssuePropsType } from '../../components/conversation/DeliveryIssueNotification';
 import type { PropsType as PaymentEventNotificationPropsType } from '../../components/conversation/PaymentEventNotification';
 import type { PropsDataType as ConversationMergePropsType } from '../../components/conversation/ConversationMergeNotification';
+import type { PropsDataType as PhoneNumberDiscoveryPropsType } from '../../components/conversation/PhoneNumberDiscoveryNotification';
 import type {
   PropsData as GroupNotificationProps,
   ChangeType,
@@ -130,7 +131,11 @@ import { calculateExpirationTimestamp } from '../../util/expirationTimer';
 import { isSignalConversation } from '../../util/isSignalConversation';
 import type { AnyPaymentEvent } from '../../types/Payment';
 import { isPaymentNotificationEvent } from '../../types/Payment';
-import { getTitleNoDefault, getNumber } from '../../util/getTitle';
+import {
+  getTitleNoDefault,
+  getNumber,
+  renderNumber,
+} from '../../util/getTitle';
 import { getMessageSentTimestamp } from '../../util/getMessageSentTimestamp';
 import type { CallHistorySelectorType } from './callHistory';
 import { CallMode } from '../../types/Calling';
@@ -951,6 +956,13 @@ export function getPropsForBubble(
       timestamp,
     };
   }
+  if (isPhoneNumberDiscovery(message)) {
+    return {
+      type: 'phoneNumberDiscovery',
+      data: getPropsForPhoneNumberDiscovery(message, options),
+      timestamp,
+    };
+  }
 
   if (
     messageHasPaymentEvent(message) &&
@@ -1517,6 +1529,34 @@ export function getPropsForConversationMerge(
   };
 }
 
+export function isPhoneNumberDiscovery(
+  message: MessageWithUIFieldsType
+): boolean {
+  return message.type === 'phone-number-discovery';
+}
+export function getPropsForPhoneNumberDiscovery(
+  message: MessageWithUIFieldsType,
+  { conversationSelector }: GetPropsForBubbleOptions
+): PhoneNumberDiscoveryPropsType {
+  const { phoneNumberDiscovery } = message;
+  if (!phoneNumberDiscovery) {
+    throw new Error(
+      'getPropsForPhoneNumberDiscovery: message is missing phoneNumberDiscovery!'
+    );
+  }
+
+  const conversation = getConversation(message, conversationSelector);
+  const conversationTitle = conversation.title;
+  const sharedGroup = conversation.sharedGroupNames[0];
+  const { e164 } = phoneNumberDiscovery;
+
+  return {
+    conversationTitle,
+    phoneNumber: renderNumber(e164) ?? e164,
+    sharedGroup,
+  };
+}
+
 // Delivery Issue
 
 export function isDeliveryIssue(message: MessageWithUIFieldsType): boolean {

ts/test-mock/pnp/phone_discovery_test.ts

@@ -0,0 +1,155 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+import { ServiceIdKind, Proto, StorageState } from '@signalapp/mock-server';
+import type { PrimaryDevice } from '@signalapp/mock-server';
+import createDebug from 'debug';
+
+import * as durations from '../../util/durations';
+import { uuidToBytes } from '../../util/uuidToBytes';
+import { MY_STORY_ID } from '../../types/Stories';
+import { toUntaggedPni } from '../../types/ServiceId';
+import { Bootstrap } from '../bootstrap';
+import type { App } from '../bootstrap';
+
+export const debug = createDebug('mock:test:merge');
+
+const IdentifierType = Proto.ManifestRecord.Identifier.Type;
+
+// PhoneNumberDiscovery notifications are also known as a Session Switchover Events (SSE).
+describe('pnp/phone discovery', function (this: Mocha.Suite) {
+  this.timeout(durations.MINUTE);
+  this.retries(4);
+
+  let bootstrap: Bootstrap;
+  let app: App;
+  let pniContact: PrimaryDevice;
+  let pniIdentityKey: Uint8Array;
+
+  beforeEach(async () => {
+    bootstrap = new Bootstrap({ contactCount: 0 });
+    await bootstrap.init();
+
+    const { server, phone } = bootstrap;
+
+    pniContact = await server.createPrimaryDevice({
+      profileName: 'ACI Contact',
+    });
+    pniIdentityKey = pniContact.getPublicKey(ServiceIdKind.PNI).serialize();
+
+    let state = StorageState.getEmpty();
+
+    state = state.updateAccount({
+      profileKey: phone.profileKey.serialize(),
+      e164: phone.device.number,
+    });
+
+    state = state.addContact(
+      pniContact,
+      {
+        identityState: Proto.ContactRecord.IdentityState.DEFAULT,
+        whitelisted: true,
+
+        identityKey: pniIdentityKey,
+
+        serviceE164: pniContact.device.number,
+      },
+      ServiceIdKind.PNI
+    );
+
+    // Put contact in left pane
+    state = state.pin(pniContact, ServiceIdKind.PNI);
+
+    // Add my story
+    state = state.addRecord({
+      type: IdentifierType.STORY_DISTRIBUTION_LIST,
+      record: {
+        storyDistributionList: {
+          allowsReplies: true,
+          identifier: uuidToBytes(MY_STORY_ID),
+          isBlockList: true,
+          name: MY_STORY_ID,
+          recipientServiceIds: [],
+        },
+      },
+    });
+
+    await phone.setStorageState(state);
+
+    app = await bootstrap.link();
+  });
+
+  afterEach(async function (this: Mocha.Context) {
+    await bootstrap.maybeSaveLogs(this.currentTest, app);
+    await app.close();
+    await bootstrap.teardown();
+  });
+
+  it('adds phone number discovery when we detect ACI/PNI association via Storage Service', async () => {
+    const { phone } = bootstrap;
+
+    const window = await app.getWindow();
+    const leftPane = window.locator('#LeftPane');
+
+    debug('opening conversation with the PNI');
+    await leftPane.locator(`[data-testid="${pniContact.device.pni}"]`).click();
+
+    debug('Send message to PNI and establish a session');
+    {
+      const compositionInput = await app.waitForEnabledComposer();
+
+      await compositionInput.type('Hello PNI');
+      await compositionInput.press('Enter');
+    }
+
+    debug(
+      'adding both contacts from storage service, adding one combined contact'
+    );
+    {
+      const state = await phone.expectStorageState('consistency check');
+      await phone.setStorageState(
+        state
+          .removeContact(pniContact, ServiceIdKind.PNI)
+          .addContact(pniContact, {
+            identityState: Proto.ContactRecord.IdentityState.DEFAULT,
+            whitelisted: true,
+            identityKey: pniContact.publicKey.serialize(),
+            profileKey: pniContact.profileKey.serialize(),
+            pni: toUntaggedPni(pniContact.device.pni),
+          })
+      );
+      await phone.sendFetchStorage({
+        timestamp: bootstrap.getTimestamp(),
+      });
+    }
+
+    await window.locator('.module-conversation-hero').waitFor();
+
+    debug('Open ACI conversation');
+    await leftPane.locator(`[data-testid="${pniContact.device.aci}"]`).click();
+
+    debug('Wait for PNI conversation to go away');
+    await window
+      .locator(`.module-conversation-hero >> ${pniContact.profileName}`)
+      .waitFor({
+        state: 'hidden',
+      });
+
+    debug('Verify final state');
+    {
+      // Should have PNI message
+      await window.locator('.module-message__text >> "Hello PNI"').waitFor();
+
+      const messages = window.locator('.module-message__text');
+      assert.strictEqual(await messages.count(), 1, 'message count');
+
+      // One notification - the PhoneNumberDiscovery
+      const notifications = window.locator('.SystemMessage');
+      assert.strictEqual(await notifications.count(), 1, 'notification count');
+
+      const first = await notifications.first();
+      assert.match(await first.innerText(), /.* belongs to ACI Contact/);
+    }
+  });
+});

ts/test-mock/pnp/pni_change_test.ts

@@ -13,6 +13,9 @@ import type { App } from '../bootstrap';
 
 export const debug = createDebug('mock:test:pni-change');
 
+// Note that all tests also generate an PhoneNumberDiscovery notification, also known as a
+// Session Switchover Event (SSE). See for reference:
+// https://github.com/signalapp/Signal-Android-Private/blob/df83c941804512c613a1010b7d8e5ce4f0aec71c/app/src/androidTest/java/org/thoughtcrime/securesms/database/RecipientTableTest_getAndPossiblyMerge.kt#L266-L270
 describe('pnp/PNI Change', function (this: Mocha.Suite) {
   this.timeout(durations.MINUTE);
   this.retries(4);
@@ -68,7 +71,7 @@ describe('pnp/PNI Change', function (this: Mocha.Suite) {
     await bootstrap.teardown();
   });
 
-  it('shows no identity change if identity key is the same', async () => {
+  it('shows phone number change if identity key is the same, learned via storage service', async () => {
     const { desktop, phone } = bootstrap;
 
     const window = await app.getWindow();
@@ -162,13 +165,16 @@ describe('pnp/PNI Change', function (this: Mocha.Suite) {
       const messages = window.locator('.module-message__text');
       assert.strictEqual(await messages.count(), 1, 'message count');
 
-      // No notifications - PNI changed, but identity key is the same
+      // Only a PhoneNumberDiscovery notification
       const notifications = window.locator('.SystemMessage');
-      assert.strictEqual(await notifications.count(), 0, 'notification count');
+      assert.strictEqual(await notifications.count(), 1, 'notification count');
+
+      const first = await notifications.first();
+      assert.match(await first.innerText(), /.* belongs to ContactA/);
     }
   });
 
-  it('shows identity change if identity key has changed', async () => {
+  it('shows identity and phone number change if identity key has changed', async () => {
     const { desktop, phone } = bootstrap;
 
     const window = await app.getWindow();
@@ -262,16 +268,19 @@ describe('pnp/PNI Change', function (this: Mocha.Suite) {
       const messages = window.locator('.module-message__text');
       assert.strictEqual(await messages.count(), 1, 'message count');
 
-      // One notification - the safety number change
+      // Two notifications - the safety number change and PhoneNumberDiscovery
       const notifications = window.locator('.SystemMessage');
-      assert.strictEqual(await notifications.count(), 1, 'notification count');
+      assert.strictEqual(await notifications.count(), 2, 'notification count');
 
       const first = await notifications.first();
-      assert.match(await first.innerText(), /Safety Number has changed/);
+      assert.match(await first.innerText(), /.* belongs to ContactA/);
+
+      const second = await notifications.nth(1);
+      assert.match(await second.innerText(), /Safety Number has changed/);
     }
   });
 
-  it('shows identity change when sending to contact', async () => {
+  it('shows identity and phone number change on send to contact when e165 has changed owners', async () => {
     const { desktop, phone } = bootstrap;
 
     const window = await app.getWindow();
@@ -395,16 +404,19 @@ describe('pnp/PNI Change', function (this: Mocha.Suite) {
       const messages = window.locator('.module-message__text');
       assert.strictEqual(await messages.count(), 2, 'message count');
 
-      // One notification - the safety number change
+      // Two notifications - the safety number change and PhoneNumberDiscovery
       const notifications = window.locator('.SystemMessage');
-      assert.strictEqual(await notifications.count(), 1, 'notification count');
+      assert.strictEqual(await notifications.count(), 2, 'notification count');
 
       const first = await notifications.first();
-      assert.match(await first.innerText(), /Safety Number has changed/);
+      assert.match(await first.innerText(), /.* belongs to ContactA/);
+
+      const second = await notifications.nth(1);
+      assert.match(await second.innerText(), /Safety Number has changed/);
     }
   });
 
-  it('Sends with no warning when key is the same', async () => {
+  it('Get phone number change warning when e164 leaves contact then goes back to same contact', async () => {
     const { desktop, phone } = bootstrap;
 
     const window = await app.getWindow();
@@ -551,9 +563,12 @@ describe('pnp/PNI Change', function (this: Mocha.Suite) {
       const messages = window.locator('.module-message__text');
       assert.strictEqual(await messages.count(), 2, 'message count');
 
-      // No notifications - the key is the same
+      // Only a PhoneNumberDiscovery notification
       const notifications = window.locator('.SystemMessage');
-      assert.strictEqual(await notifications.count(), 0, 'notification count');
+      assert.strictEqual(await notifications.count(), 1, 'notification count');
+
+      const first = await notifications.first();
+      assert.match(await first.innerText(), /.* belongs to ContactA/);
     }
   });
 });

ts/util/getStringForPhoneNumberDiscovery.ts

@@ -0,0 +1,29 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { LocalizerType } from '../types/Util';
+
+export function getStringForPhoneNumberDiscovery({
+  phoneNumber,
+  i18n,
+  conversationTitle,
+  sharedGroup,
+}: {
+  phoneNumber: string;
+  i18n: LocalizerType;
+  conversationTitle: string;
+  sharedGroup?: string;
+}): string {
+  if (sharedGroup) {
+    return i18n('icu:PhoneNumberDiscovery--notification--withSharedGroup', {
+      phoneNumber,
+      conversationTitle,
+      sharedGroup,
+    });
+  }
+
+  return i18n('icu:PhoneNumberDiscovery--notification--noSharedGroup', {
+    phoneNumber,
+    conversationTitle,
+  });
+}