🐛 Fix issue that IMAP node can crash n8n

packages/cli/src/ActiveWorkflowRunner.ts

@@ -682,6 +682,15 @@ export class ActiveWorkflowRunner {
 					(error) => console.error(error),
 				);
 			};
+			returnFunctions.emitError = async (error: Error): Promise<void> => {
+				await this.activeWorkflows?.remove(workflowData.id.toString());
+				this.activationErrors[workflowData.id.toString()] = {
+					time: new Date().getTime(),
+					error: {
+						message: error.message,
+					},
+				};
+			};
 			return returnFunctions;
 		};
 	}

packages/core/src/NodeExecuteFunctions.ts

@@ -1750,6 +1750,9 @@ export function getExecuteTriggerFunctions(
 			emit: (data: INodeExecutionData[][]): void => {
 				throw new Error('Overwrite NodeExecuteFunctions.getExecuteTriggerFunctions.emit function!');
 			},
+			emitError: (error: Error): void => {
+				throw new Error('Overwrite NodeExecuteFunctions.getExecuteTriggerFunctions.emit function!');
+			},
 			async getCredentials(type: string): Promise<ICredentialDataDecryptedObject | undefined> {
 				return getCredentials(workflow, node, type, additionalData, mode);
 			},

packages/nodes-base/nodes/EmailReadImap/EmailReadImap.node.ts

@@ -1,13 +1,15 @@
 import { ITriggerFunctions } from 'n8n-core';
 import {
+	createDeferredPromise,
 	IBinaryData,
 	IBinaryKeyData,
 	IDataObject,
+	IDeferredPromise,
 	INodeExecutionData,
 	INodeType,
 	INodeTypeDescription,
 	ITriggerResponse,
-	LoggerProxy,
+	LoggerProxy as Logger,
 	NodeOperationError,
 } from 'n8n-workflow';
 
@@ -25,10 +27,6 @@ import {
 
 import * as lodash from 'lodash';
 
-import {
-	LoggerProxy as Logger
-} from 'n8n-workflow';
-
 export class EmailReadImap implements INodeType {
 	description: INodeTypeDescription = {
 		displayName: 'EmailReadImap',
@@ -377,6 +375,8 @@ export class EmailReadImap implements INodeType {
 			return newEmails;
 		};
 
+		const returnedPromise: IDeferredPromise<void> | undefined = await createDeferredPromise<void>();
+
 		const establishConnection = (): Promise<ImapSimple> => {
 
 			let searchCriteria = [
@@ -425,7 +425,11 @@ export class EmailReadImap implements INodeType {
 							}
 						} catch (error) {
 							Logger.error('Email Read Imap node encountered an error fetching new emails', { error });
-							throw error;
+							// Wait with resolving till the returnedPromise got resolved, else n8n will be unhappy
+							// if it receives an error before the workflow got activated
+							returnedPromise.promise().then(() => {
+								this.emitError(error as Error);
+							});
 						}
 					}
 				},
@@ -475,10 +479,12 @@ export class EmailReadImap implements INodeType {
 			await connection.end();
 		}
 
+		// Resolve returned-promise so that waiting errors can be emitted
+		returnedPromise.resolve();
+
 		return {
 			closeFunction,
 		};
-
 	}
 }
 

packages/workflow/src/Interfaces.ts

@@ -683,6 +683,7 @@ export interface ITriggerFunctions {
 		data: INodeExecutionData[][],
 		responsePromise?: IDeferredPromise<IExecuteResponsePromiseData>,
 	): void;
+	emitError(error: Error, responsePromise?: IDeferredPromise<IExecuteResponsePromiseData>): void;
 	getCredentials(type: string): Promise<ICredentialDataDecryptedObject | undefined>;
 	getMode(): WorkflowExecuteMode;
 	getActivationMode(): WorkflowActivateMode;

packages/workflow/src/Workflow.ts

@@ -949,7 +949,7 @@ export class Workflow {
 			const triggerResponse = await nodeType.trigger.call(triggerFunctions);
 
 			// Add the manual trigger response which resolves when the first time data got emitted
-			triggerResponse!.manualTriggerResponse = new Promise((resolve) => {
+			triggerResponse!.manualTriggerResponse = new Promise((resolve, reject) => {
 				triggerFunctions.emit = (
 					(resolveEmit) =>
 					(
@@ -967,6 +967,20 @@ export class Workflow {
 						resolveEmit(data);
 					}
 				)(resolve);
+				triggerFunctions.emitError = (
+					(rejectEmit) =>
+					(error: Error, responsePromise?: IDeferredPromise<IExecuteResponsePromiseData>) => {
+						additionalData.hooks!.hookFunctions.sendResponse = [
+							async (): Promise<void> => {
+								if (responsePromise) {
+									responsePromise.reject(error);
+								}
+							},
+						];
+
+						rejectEmit(error);
+					}
+				)(reject);
 			});
 
 			return triggerResponse;