fix: Bug - Attachments gets syncronized corrupt

e2e/tests/chat/chat-message-features.spec.ts

@@ -1,3 +1,4 @@
+import { createHash, randomBytes } from 'node:crypto';
 import { type Page } from '@playwright/test';
 import {
   test,
@@ -182,6 +183,28 @@ test.describe('Chat messaging features', () => {
     });
   });
 
+  test('syncs multi-chunk image attachments byte-identical between users', async ({ createClient }) => {
+    const scenario = await createChatScenario(createClient);
+    const imageName = `${uniqueName('photo')}.svg`;
+    const imageCaption = `Large image upload ${uniqueName('caption')}`;
+    // Several P2P file chunks (64 KiB each) - regression coverage for transfers
+    // that previously finalized with only the first chunks received.
+    const { payload, sha256 } = createMultiChunkImagePayload(imageName);
+
+    await test.step('Alice sends a multi-chunk image attachment', async () => {
+      await scenario.aliceMessages.attachFiles([payload]);
+      await scenario.aliceMessages.sendMessage(imageCaption);
+
+      await scenario.aliceMessages.expectMessageImageLoaded(imageName);
+      await scenario.aliceMessages.expectMessageImageContentSha256(imageName, sha256);
+    });
+
+    await test.step('Bob receives the image fully and byte-identical', async () => {
+      await expect(scenario.bobMessages.getMessageItemByText(imageCaption)).toBeVisible({ timeout: 20_000 });
+      await scenario.bobMessages.expectMessageImageContentSha256(imageName, sha256);
+    });
+  });
+
   test('renders link embeds for shared links', async ({ createClient }) => {
     const scenario = await createChatScenario(createClient);
     const messageText = `Useful docs ${MOCK_EMBED_URL}`;
@@ -442,6 +465,24 @@ function createTextFilePayload(name: string, mimeType: string, content: string):
   };
 }
 
+function createMultiChunkImagePayload(name: string): { payload: ChatDropFilePayload; sha256: string } {
+  // ~300 KB of XML-safe noise inside an SVG comment so the file spans
+  // multiple 64 KiB P2P transfer chunks while remaining a renderable image.
+  const noise = randomBytes(225_000).toString('base64');
+  const markup = buildMockSvgMarkup(name).replace('</svg>', `<!-- ${noise} --></svg>`);
+  const contentBuffer = Buffer.from(markup, 'utf8');
+
+  return {
+    payload: {
+      name,
+      mimeType: 'image/svg+xml',
+      base64: contentBuffer.toString('base64')
+    },
+    sha256: createHash('sha256').update(contentBuffer)
+      .digest('hex')
+  };
+}
+
 function buildMockSvgMarkup(label: string): string {
   return [
     '<svg xmlns="http://www.w3.org/2000/svg" width="160" height="120" viewBox="0 0 160 120">',