fix(Gmail Trigger Node): Don't return date instances, but date strings instead (#10582)

packages/nodes-base/nodes/Google/Gmail/GenericFunctions.ts

@@ -202,6 +202,11 @@ export async function parseRawEmail(
 		headers,
 		headerLines: undefined,
 		attachments: undefined,
+		// Having data in IDataObjects that is not representable in JSON leads to
+		// inconsistencies between test executions and production executions.
+		// During a manual execution this would be stringified and during a
+		// production execution the next node would receive a date instance.
+		date: responseData.date ? responseData.date.toISOString() : responseData.date,
 	}) as IDataObject;
 
 	return {

packages/nodes-base/nodes/Google/Gmail/test/v2/utils.test.ts

@@ -1,6 +1,7 @@
-import type { INode } from 'n8n-workflow';
+import type { IExecuteFunctions, INode } from 'n8n-workflow';
 import { DateTime } from 'luxon';
-import { prepareTimestamp } from '../../GenericFunctions';
+import { mock } from 'jest-mock-extended';
+import { parseRawEmail, prepareTimestamp } from '../../GenericFunctions';
 
 const node: INode = {
 	id: '1',
@@ -108,3 +109,21 @@ describe('Google Gmail v2, prepareTimestamp', () => {
 		);
 	});
 });
+
+describe('parseRawEmail', () => {
+	it('should return a date string', async () => {
+		// ARRANGE
+		const executionFunctions = mock<IExecuteFunctions>();
+		const rawEmail = 'Date: Wed, 28 Aug 2024 00:36:37 -0700'.replace(/\n/g, '\r\n');
+
+		// ACT
+		const { json } = await parseRawEmail.call(
+			executionFunctions,
+			{ raw: Buffer.from(rawEmail, 'utf8').toString('base64') },
+			'attachment_',
+		);
+
+		// ASSERT
+		expect(typeof json.date).toBe('string');
+	});
+});