fix: Prevent empty path in webhooks (#16864)

Co-authored-by: Roman Davydchuk <roman.davydchuk@n8n.io>

packages/workflow/test/node-helpers.test.ts

@@ -21,8 +21,10 @@ import {
 	isDefaultNodeName,
 	makeNodeName,
 	isTool,
+	getNodeWebhookPath,
 } from '../src/node-helpers';
 import type { Workflow } from '../src/workflow';
+import { mock } from 'vitest-mock-extended';
 
 describe('NodeHelpers', () => {
 	describe('getNodeParameters', () => {
@@ -4382,6 +4384,7 @@ describe('NodeHelpers', () => {
 			test(testData.description, () => {
 				// If this test has a custom mock return value, configure it
 				if (testData.mockReturnValue) {
+					// eslint-disable-next-line @typescript-eslint/unbound-method
 					vi.mocked(workflowMock.expression.getSimpleParameterValue).mockReturnValueOnce(
 						testData.mockReturnValue,
 					);
@@ -5611,4 +5614,48 @@ describe('NodeHelpers', () => {
 			expect(result).toBe(false);
 		});
 	});
+	describe('getNodeWebhookPath', () => {
+		const mockWorkflowId = 'workflow-123';
+		const mockPath = 'test-path';
+
+		it('should return path when restartWebhook is true', () => {
+			const node = mock<INode>({ name: 'TestNode' });
+
+			const result = getNodeWebhookPath(mockWorkflowId, node, mockPath, false, true);
+
+			expect(result).toBe(mockPath);
+		});
+
+		it('should return path when node has webhookId and isFullPath is true', () => {
+			const node = mock<INode>({ name: 'TestNode', webhookId: 'webhook-456' });
+
+			const result = getNodeWebhookPath(mockWorkflowId, node, mockPath, true, false);
+
+			expect(result).toBe(mockPath);
+		});
+
+		it('should return webhookId when node has webhookId, isFullPath is true, and path is empty', () => {
+			const node = mock<INode>({ name: 'TestNode', webhookId: 'webhook-456' });
+
+			const result = getNodeWebhookPath(mockWorkflowId, node, '', true, false);
+
+			expect(result).toBe('webhook-456');
+		});
+
+		it('should return webhookId/path when node has webhookId and isFullPath is false', () => {
+			const node = mock<INode>({ name: 'TestNode', webhookId: 'webhook-456' });
+
+			const result = getNodeWebhookPath(mockWorkflowId, node, mockPath, false, false);
+
+			expect(result).toBe('webhook-456/test-path');
+		});
+
+		it('should return workflowId/nodename/path when node has no webhookId', () => {
+			const node = mock<INode>({ name: 'TestNode', webhookId: undefined });
+
+			const result = getNodeWebhookPath(mockWorkflowId, node, mockPath, false, false);
+
+			expect(result).toBe('workflow-123/testnode/test-path');
+		});
+	});
 });