fix(core): Remove circular refs from Code and push msg (#5741)

* remove circular refs from code items (and lint fixes)

* cleanup

---------

* add some tests

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/cli/src/push/abstract.push.ts

@@ -1,4 +1,4 @@
-import { LoggerProxy as Logger } from 'n8n-workflow';
+import { jsonStringify, LoggerProxy as Logger } from 'n8n-workflow';
 import type { IPushDataType } from '@/Interfaces';
 import { eventBus } from '../eventbus';
 
@@ -38,7 +38,7 @@ export abstract class AbstractPush<T> {
 
 		Logger.debug(`Send data of type "${type}" to editor-UI`, { dataType: type, sessionId });
 
-		const sendData = JSON.stringify({ type, data });
+		const sendData = jsonStringify({ type, data }, { replaceCircularRefs: true });
 
 		if (sessionId === undefined) {
 			// Send to all connected clients

packages/cli/src/sso/saml/routes/saml.controller.ee.ts

@@ -135,7 +135,6 @@ export class SamlController {
 	private async handleInitSSO(res: express.Response) {
 		const result = this.samlService.getLoginRequestUrl();
 		if (result?.binding === 'redirect') {
-			// Return the redirect URL directly
 			return res.send(result.context.context);
 		} else if (result?.binding === 'post') {
 			return res.send(getInitSSOFormView(result.context as PostBindingContext));

packages/nodes-base/nodes/Code/utils.ts

@@ -12,15 +12,28 @@ function isTraversable(maybe: unknown): maybe is IDataObject {
  * Stringify any non-standard JS objects (e.g. `Date`, `RegExp`) inside output items at any depth.
  */
 export function standardizeOutput(output: IDataObject) {
-	for (const [key, value] of Object.entries(output)) {
+	const knownObjects = new WeakSet();
+
+	function standardizeOutputRecursive(obj: IDataObject): IDataObject {
+		for (const [key, value] of Object.entries(obj)) {
 			if (!isTraversable(value)) continue;
 
-		output[key] =
-			value.constructor.name !== 'Object'
-				? JSON.stringify(value) // Date, RegExp, etc.
-				: standardizeOutput(value);
+			if (typeof value === 'object' && value !== null) {
+				if (knownObjects.has(value)) {
+					// Found circular reference
+					continue;
+				}
+				knownObjects.add(value);
 			}
 
+			obj[key] =
+				value.constructor.name !== 'Object'
+					? JSON.stringify(value) // Date, RegExp, etc.
+					: standardizeOutputRecursive(value);
+		}
+		return obj;
+	}
+	standardizeOutputRecursive(output);
 	return output;
 }
 

packages/workflow/src/index.ts

@@ -23,7 +23,7 @@ export * from './WorkflowErrors';
 export * from './WorkflowHooks';
 export * from './VersionedNodeType';
 export { LoggerProxy, NodeHelpers, ObservableObject, TelemetryHelpers };
-export { deepCopy, jsonParse, sleep, fileTypeFromMimeType, assert } from './utils';
+export { deepCopy, jsonParse, jsonStringify, sleep, fileTypeFromMimeType, assert } from './utils';
 export {
 	isINodeProperties,
 	isINodePropertyOptions,

packages/workflow/src/utils.ts

@@ -62,6 +62,31 @@ export const jsonParse = <T>(jsonString: string, options?: JSONParseOptions<T>):
 	}
 };
 
+type JSONStringifyOptions = {
+	replaceCircularRefs?: boolean;
+	circularRefReplacement?: string;
+};
+
+const getReplaceCircularReferencesFn = (options: JSONStringifyOptions) => {
+	const knownObjects = new WeakSet();
+	return (key: any, value: any) => {
+		if (typeof value === 'object' && value !== null) {
+			if (knownObjects.has(value)) {
+				return options?.circularRefReplacement ?? '[Circular Reference]';
+			}
+			knownObjects.add(value);
+		}
+		return value;
+	};
+};
+
+export const jsonStringify = (obj: unknown, options: JSONStringifyOptions = {}): string => {
+	const replacer = options?.replaceCircularRefs
+		? getReplaceCircularReferencesFn(options)
+		: undefined;
+	return JSON.stringify(obj, replacer);
+};
+
 export const sleep = async (ms: number): Promise<void> =>
 	new Promise((resolve) => {
 		setTimeout(resolve, ms);

packages/workflow/test/utils.test.ts

@@ -1,4 +1,4 @@
-import { jsonParse, deepCopy } from '@/utils';
+import { jsonParse, jsonStringify, deepCopy } from '@/utils';
 
 describe('jsonParse', () => {
 	it('parses JSON', () => {
@@ -17,6 +17,21 @@ describe('jsonParse', () => {
 	});
 });
 
+describe('jsonStringify', () => {
+	const source: any = { a: 1, b: 2 };
+	source.c = source;
+
+	it('should throw errors on circular references by default', () => {
+		expect(() => jsonStringify(source)).toThrow('Converting circular structure to JSON');
+	});
+
+	it('should break circular references when requested', () => {
+		expect(jsonStringify(source, { replaceCircularRefs: true })).toEqual(
+			'{"a":1,"b":2,"c":"[Circular Reference]"}',
+		);
+	});
+});
+
 describe('deepCopy', () => {
 	it('should deep copy an object', () => {
 		const serializable = {