From df2fa3c7b10199acf32c3f2915b532d64518d5a2 Mon Sep 17 00:00:00 2001
From: Josh Perez <60019601+josh-signal@users.noreply.github.com>
Date: Tue, 20 Oct 2020 19:26:58 -0400
Subject: [PATCH] updateLastMessage: Use MessageController for latest data

---
 test/index.html                   |  1 +
 test/models/conversations_test.js | 70 +++++++++++++++++++++++++++++++
 ts/models/conversations.ts        | 19 ++++++++-
 3 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 test/models/conversations_test.js

diff --git a/test/index.html b/test/index.html
index 5b3edb4716..fb41bf32ed 100644
--- a/test/index.html
+++ b/test/index.html
@@ -376,6 +376,7 @@
   <script type="text/javascript" src="views/list_view_test.js"></script>
 
   <script type="text/javascript" src="models/messages_test.js"></script>
+  <script type="text/javascript" src="models/conversations_test.js"></script>
 
   <script type="text/javascript" src="libphonenumber_util_test.js"></script>
   <script type="text/javascript" src="storage_test.js"></script>
diff --git a/test/models/conversations_test.js b/test/models/conversations_test.js
new file mode 100644
index 0000000000..7889bd2810
--- /dev/null
+++ b/test/models/conversations_test.js
@@ -0,0 +1,70 @@
+describe('Conversations', () => {
+  it('updates lastMessage even in race conditions with db', async () => {
+    // Creating a fake conversation
+    const conversation = new window.Whisper.Conversation({
+      id: '8c45efca-67a4-4026-b990-9537d5d1a08f',
+      e164: '+15551234567',
+      uuid: '2f2734aa-f69d-4c1c-98eb-50eb0fc512d7',
+      type: 'private',
+    });
+
+    const destinationE164 = '+15557654321';
+
+    // Creating a fake message
+    const now = Date.now();
+    let message = new window.Whisper.Message({
+      attachments: [],
+      body: 'bananas',
+      conversationId: conversation.id,
+      delivered: 1,
+      delivered_to: [destinationE164],
+      destination: destinationE164,
+      expirationStartTimestamp: now,
+      hasAttachments: 0,
+      hasFileAttachments: 0,
+      hasVisualMediaAttachments: 0,
+      id: 'd8f2b435-e2ef-46e0-8481-07e68af251c6',
+      received_at: now,
+      recipients: [destinationE164],
+      sent: true,
+      sent_at: now,
+      sent_to: [destinationE164],
+      timestamp: now,
+      type: 'outgoing',
+    });
+
+    // Saving to db and updating the convo's last message
+    await window.Signal.Data.saveMessage(message.attributes, {
+      forceSave: true,
+      Message: window.Whisper.Message,
+    });
+    message = window.MessageController.register(message.id, message);
+    await window.Signal.Data.saveConversation(conversation.attributes, {
+      Conversation: window.Whisper.Conversation,
+    });
+    await conversation.updateLastMessage();
+
+    // Should be set to bananas because that's the last message sent.
+    assert.strictEqual(conversation.get('lastMessage'), 'bananas');
+
+    // Erasing message contents (DOE)
+    message.set({
+      isErased: true,
+      body: '',
+      bodyRanges: undefined,
+      attachments: [],
+      quote: null,
+      contact: [],
+      sticker: null,
+      preview: [],
+    });
+
+    // Not saving the message to db on purpose
+    // to simulate that a save hasn't taken place yet.
+
+    // Updating convo's last message, should pick it up from memory
+    await conversation.updateLastMessage();
+
+    assert.strictEqual(conversation.get('lastMessage'), '');
+  });
+});
diff --git a/ts/models/conversations.ts b/ts/models/conversations.ts
index e4d8e4214b..f31298ecd7 100644
--- a/ts/models/conversations.ts
+++ b/ts/models/conversations.ts
@@ -2874,7 +2874,7 @@ export class ConversationModel extends window.Backbone.Model<
       return;
     }
 
-    const [previewMessage, activityMessage] = await Promise.all([
+    let [previewMessage, activityMessage] = await Promise.all([
       window.Signal.Data.getLastConversationPreview(this.id, {
         Message: window.Whisper.Message,
       }),
@@ -2883,6 +2883,23 @@ export class ConversationModel extends window.Backbone.Model<
       }),
     ]);
 
+    // Register the message with MessageController so that if it already exists
+    // in memory we use that data instead of the data from the db which may
+    // be out of date.
+    if (previewMessage) {
+      previewMessage = window.MessageController.register(
+        previewMessage.id,
+        previewMessage
+      );
+    }
+
+    if (activityMessage) {
+      activityMessage = window.MessageController.register(
+        activityMessage.id,
+        activityMessage
+      );
+    }
+
     if (
       this.hasDraft() &&
       this.get('draftTimestamp') &&