Desktop: Fixes #11759: Preserve attachment file extensions regardless of the mime type (#11852)

Co-authored-by: Laurent Cozic <laurent22@users.noreply.github.com>

Author: pedr

packages/lib/shim-init-node.test.ts

@@ -2,6 +2,7 @@
 const { shimInit } = require('./shim-init-node');
 import shim from './shim';
 import { setupDatabaseAndSynchronizer, supportDir } from './testing/test-utils';
+import { copyFile } from 'fs-extra';
 
 describe('shim-init-node', () => {
 
@@ -10,10 +11,21 @@ describe('shim-init-node', () => {
 		shimInit();
 	});
 
-	test('should set mime the correct mime for a PDF file even if the extension is missing', async () => {
+	test('should set the correct mime for a PDF file even if the extension is missing', async () => {
 		const filePath = `${supportDir}/valid_pdf_without_ext`;
 		const resource = await shim.createResourceFromPath(filePath);
 
 		expect(resource.mime).toBe('application/pdf');
 	});
+
+	test('should preserve the file extension if one is provided regardless of the mime type', async () => {
+		const originalFilePath = `${supportDir}/valid_pdf_without_ext`;
+		const fileWithDifferentExtension = `${originalFilePath}.mscz`;
+		await copyFile(originalFilePath, fileWithDifferentExtension);
+
+		const resource = await shim.createResourceFromPath(fileWithDifferentExtension);
+
+		expect(resource.file_extension).toBe('mscz');
+	});
+
 });

packages/lib/shim-init-node.ts

@@ -344,7 +344,7 @@ function shimInit(options: ShimInitOptions = null) {
 			const detectedType = await fileTypeFromFile(filePath);
 
 			if (detectedType) {
-				fileExt = detectedType.ext;
+				fileExt = fileExt ? fileExt : detectedType.ext;
 				resource.mime = detectedType.mime;
 			} else {
 				resource.mime = 'application/octet-stream';