feat(Code Node): Warning if pairedItem absent or could not be auto mapped (#11737)

Co-authored-by: Shireen Missi <shireen@n8n.io>

packages/editor-ui/src/components/AssignmentCollection/Assignment.vue

@@ -5,6 +5,7 @@ import ParameterInputFull from '@/components/ParameterInputFull.vue';
 import ParameterInputHint from '@/components/ParameterInputHint.vue';
 import ParameterIssues from '@/components/ParameterIssues.vue';
 import { useWorkflowHelpers } from '@/composables/useWorkflowHelpers';
+import { useWorkflowsStore } from '@/stores/workflows.store';
 import { isExpression, stringifyExpressionResult } from '@/utils/expressions';
 import type { AssignmentValue, INodeProperties, Result } from 'n8n-workflow';
 import { computed, ref } from 'vue';
@@ -101,7 +102,12 @@ const hint = computed(() => {
 		result = { ok: false, error };
 	}
 
-	return stringifyExpressionResult(result);
+	const hasRunData =
+		!!useWorkflowsStore().workflowExecutionData?.data?.resultData?.runData[
+			ndvStore.activeNode?.name ?? ''
+		];
+
+	return stringifyExpressionResult(result, hasRunData);
 });
 
 const highlightHint = computed(() => Boolean(hint.value && ndvStore.getHoveringItem));

packages/editor-ui/src/components/ParameterInputWrapper.vue

@@ -22,6 +22,7 @@ import type { EventBus } from 'n8n-design-system/utils';
 import { createEventBus } from 'n8n-design-system/utils';
 import { computed } from 'vue';
 import { useRouter } from 'vue-router';
+import { useWorkflowsStore } from '@/stores/workflows.store';
 
 type Props = {
 	parameter: INodeProperties;
@@ -144,7 +145,11 @@ const evaluatedExpressionValue = computed(() => {
 });
 
 const evaluatedExpressionString = computed(() => {
-	return stringifyExpressionResult(evaluatedExpression.value);
+	const hasRunData =
+		!!useWorkflowsStore().workflowExecutionData?.data?.resultData?.runData[
+			ndvStore.activeNode?.name ?? ''
+		];
+	return stringifyExpressionResult(evaluatedExpression.value, hasRunData);
 });
 
 const expressionOutput = computed(() => {

packages/editor-ui/src/composables/useExpressionEditor.ts

@@ -305,7 +305,11 @@ export const useExpressionEditor = ({
 				result.resolved = workflowHelpers.resolveExpression('=' + resolvable, undefined, opts);
 			}
 		} catch (error) {
-			result.resolved = `[${getExpressionErrorMessage(error)}]`;
+			const hasRunData =
+				!!workflowsStore.workflowExecutionData?.data?.resultData?.runData[
+					ndvStore.activeNode?.name ?? ''
+				];
+			result.resolved = `[${getExpressionErrorMessage(error, hasRunData)}]`;
 			result.error = true;
 			result.fullError = error;
 		}

packages/editor-ui/src/plugins/i18n/locales/en.json

@@ -834,6 +834,7 @@
 	"expressionModalInput.pairedItemConnectionError": "No path back to node",
 	"expressionModalInput.pairedItemInvalidPinnedError": "Unpin node ‘{node}’ and execute",
 	"expressionModalInput.pairedItemError": "Can’t determine which item to use",
+	"expressionModalInput.pairedItemError.noRunData": "Can't determine which item to use - execute node for more info",
 	"fixedCollectionParameter.choose": "Choose...",
 	"fixedCollectionParameter.currentlyNoItemsExist": "Currently no items exist",
 	"fixedCollectionParameter.deleteItem": "Delete item",

packages/editor-ui/src/utils/expressions.ts

@@ -78,7 +78,7 @@ export const getResolvableState = (error: unknown, ignoreError = false): Resolva
 	return 'invalid';
 };
 
-export const getExpressionErrorMessage = (error: Error): string => {
+export const getExpressionErrorMessage = (error: Error, nodeHasRunData = false): string => {
 	if (isNoExecDataExpressionError(error) || isPairedItemIntermediateNodesError(error)) {
 		return i18n.baseText('expressionModalInput.noExecutionData');
 	}
@@ -109,19 +109,24 @@ export const getExpressionErrorMessage = (error: Error): string => {
 	}
 
 	if (isAnyPairedItemError(error)) {
-		return i18n.baseText('expressionModalInput.pairedItemError');
+		return nodeHasRunData
+			? i18n.baseText('expressionModalInput.pairedItemError')
+			: i18n.baseText('expressionModalInput.pairedItemError.noRunData');
 	}
 
 	return error.message;
 };
 
-export const stringifyExpressionResult = (result: Result<unknown, Error>): string => {
+export const stringifyExpressionResult = (
+	result: Result<unknown, Error>,
+	nodeHasRunData = false,
+): string => {
 	if (!result.ok) {
 		if (getResolvableState(result.error) !== 'invalid') {
 			return '';
 		}
 
-		return `[${i18n.baseText('parameterInput.error')}: ${getExpressionErrorMessage(result.error)}]`;
+		return `[${i18n.baseText('parameterInput.error')}: ${getExpressionErrorMessage(result.error, nodeHasRunData)}]`;
 	}
 
 	if (result.result === null) {

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

@@ -17,7 +17,7 @@ import { JavaScriptSandbox } from './JavaScriptSandbox';
 import { JsTaskRunnerSandbox } from './JsTaskRunnerSandbox';
 import { PythonSandbox } from './PythonSandbox';
 import { getSandboxContext } from './Sandbox';
-import { standardizeOutput } from './utils';
+import { addPostExecutionWarning, standardizeOutput } from './utils';
 
 const { CODE_ENABLE_STDOUT } = process.env;
 
@@ -142,6 +142,8 @@ export class Code implements INodeType {
 			return sandbox;
 		};
 
+		const inputDataItems = this.getInputData();
+
 		// ----------------------------------
 		//        runOnceForAllItems
 		// ----------------------------------
@@ -163,7 +165,7 @@ export class Code implements INodeType {
 				standardizeOutput(item.json);
 			}
 
-			return [items];
+			return addPostExecutionWarning(items, inputDataItems?.length);
 		}
 
 		// ----------------------------------
@@ -172,9 +174,7 @@ export class Code implements INodeType {
 
 		const returnData: INodeExecutionData[] = [];
 
-		const items = this.getInputData();
-
-		for (let index = 0; index < items.length; index++) {
+		for (let index = 0; index < inputDataItems.length; index++) {
 			const sandbox = getSandbox(index);
 			let result: INodeExecutionData | undefined;
 			try {
@@ -201,6 +201,6 @@ export class Code implements INodeType {
 			}
 		}
 
-		return [returnData];
+		return addPostExecutionWarning(returnData, inputDataItems?.length);
 	}
 }

packages/nodes-base/nodes/Code/test/Code.node.test.ts

@@ -57,7 +57,8 @@ describe('Code Node unit test', () => {
 					jest.spyOn(NodeVM.prototype, 'run').mockResolvedValueOnce(input);
 
 					const output = await node.execute.call(thisArg);
-					expect(output).toEqual([expected]);
+
+					expect([...output]).toEqual([expected]);
 				}),
 			);
 		});
@@ -109,7 +110,7 @@ describe('Code Node unit test', () => {
 					jest.spyOn(NodeVM.prototype, 'run').mockResolvedValueOnce(input);
 
 					const output = await node.execute.call(thisArg);
-					expect(output).toEqual([[{ json: expected?.json, pairedItem: { item: 0 } }]]);
+					expect([...output]).toEqual([[{ json: expected?.json, pairedItem: { item: 0 } }]]);
 				}),
 			);
 		});

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

@@ -0,0 +1,48 @@
+import type { INodeExecutionData } from 'n8n-workflow';
+import { NodeExecutionOutput } from 'n8n-workflow';
+import { addPostExecutionWarning } from '../utils';
+
+describe('addPostExecutionWarning', () => {
+	const inputItemsLength = 2;
+
+	it('should return a NodeExecutionOutput warning when returnData length differs from inputItemsLength', () => {
+		const returnData: INodeExecutionData[] = [{ json: {}, pairedItem: 0 }];
+
+		const result = addPostExecutionWarning(returnData, inputItemsLength);
+
+		expect(result).toBeInstanceOf(NodeExecutionOutput);
+		expect((result as NodeExecutionOutput)?.getHints()).toEqual([
+			{
+				message:
+					'To make sure expressions after this node work, return the input items that produced each output item. <a target="_blank" href="https://docs.n8n.io/data/data-mapping/data-item-linking/item-linking-code-node/">More info</a>',
+				location: 'outputPane',
+			},
+		]);
+	});
+
+	it('should return a NodeExecutionOutput warning when any item has undefined pairedItem', () => {
+		const returnData: INodeExecutionData[] = [{ json: {}, pairedItem: 0 }, { json: {} }];
+
+		const result = addPostExecutionWarning(returnData, inputItemsLength);
+
+		expect(result).toBeInstanceOf(NodeExecutionOutput);
+		expect((result as NodeExecutionOutput)?.getHints()).toEqual([
+			{
+				message:
+					'To make sure expressions after this node work, return the input items that produced each output item. <a target="_blank" href="https://docs.n8n.io/data/data-mapping/data-item-linking/item-linking-code-node/">More info</a>',
+				location: 'outputPane',
+			},
+		]);
+	});
+
+	it('should return returnData array when all items match inputItemsLength and have defined pairedItem', () => {
+		const returnData: INodeExecutionData[] = [
+			{ json: {}, pairedItem: 0 },
+			{ json: {}, pairedItem: 1 },
+		];
+
+		const result = addPostExecutionWarning(returnData, inputItemsLength);
+
+		expect(result).toEqual([returnData]);
+	});
+});

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

@@ -1,4 +1,5 @@
-import type { IDataObject } from 'n8n-workflow';
+import type { INodeExecutionData, IDataObject } from 'n8n-workflow';
+import { NodeExecutionOutput } from 'n8n-workflow';
 
 export function isObject(maybe: unknown): maybe is { [key: string]: unknown } {
 	return (
@@ -36,3 +37,26 @@ export function standardizeOutput(output: IDataObject) {
 	standardizeOutputRecursive(output);
 	return output;
 }
+
+export const addPostExecutionWarning = (
+	returnData: INodeExecutionData[],
+	inputItemsLength: number,
+) => {
+	if (
+		returnData.length !== inputItemsLength ||
+		returnData.some((item) => item.pairedItem === undefined)
+	) {
+		return new NodeExecutionOutput(
+			[returnData],
+			[
+				{
+					message:
+						'To make sure expressions after this node work, return the input items that produced each output item. <a target="_blank" href="https://docs.n8n.io/data/data-mapping/data-item-linking/item-linking-code-node/">More info</a>',
+					location: 'outputPane',
+				},
+			],
+		);
+	}
+
+	return [returnData];
+};