Add error marker when invalid main function (#9489)

## Before

![image](https://github.com/user-attachments/assets/f6af6721-0896-48b5-8556-9d2a9c19de06)

## After

![image](https://github.com/user-attachments/assets/c59407c8-8244-4906-9d05-713909a19c33)

packages/twenty-front/src/modules/workflow/workflow-steps/workflow-actions/components/WorkflowEditActionFormServerlessFunction.tsx

@@ -8,6 +8,7 @@ import { WorkflowCodeAction } from '@/workflow/types/Workflow';
 import { WorkflowStepHeader } from '@/workflow/workflow-steps/components/WorkflowStepHeader';
 import { setNestedValue } from '@/workflow/workflow-steps/workflow-actions/utils/setNestedValue';
 
+import { Monaco } from '@monaco-editor/react';
 import { CmdEnterActionButton } from '@/action-menu/components/CmdEnterActionButton';
 import { ServerlessFunctionExecutionResult } from '@/serverless-functions/components/ServerlessFunctionExecutionResult';
 import { INDEX_FILE_PATH } from '@/serverless-functions/constants/IndexFilePath';
@@ -26,13 +27,13 @@ import { WORKFLOW_SERVERLESS_FUNCTION_TAB_LIST_COMPONENT_ID } from '@/workflow/w
 import { WorkflowVariablePicker } from '@/workflow/workflow-variables/components/WorkflowVariablePicker';
 import { useTheme } from '@emotion/react';
 import styled from '@emotion/styled';
-import { Monaco } from '@monaco-editor/react';
 import { editor } from 'monaco-editor';
 import { AutoTypings } from 'monaco-editor-auto-typings';
 import { useEffect, useState } from 'react';
 import { useRecoilState, useRecoilValue } from 'recoil';
 import { CodeEditor, IconCode, IconPlayerPlay, isDefined } from 'twenty-ui';
 import { useDebouncedCallback } from 'use-debounce';
+import { getWrongExportedFunctionMarkers } from '@/workflow/workflow-steps/workflow-actions/utils/getWrongExportedFunctionMarkers';
 
 const StyledContainer = styled.div`
   display: flex;
@@ -299,6 +300,7 @@ export const WorkflowEditActionFormServerlessFunction = ({
                   language={'typescript'}
                   onChange={handleCodeChange}
                   onMount={handleEditorDidMount}
+                  setMarkers={getWrongExportedFunctionMarkers}
                   options={{
                     readOnly: actionOptions.readonly,
                     domReadOnly: actionOptions.readonly,

packages/twenty-front/src/modules/workflow/workflow-steps/workflow-actions/utils/__tests__/getWrongExportedFunctionMarkers.test.ts

@@ -0,0 +1,30 @@
+import { getWrongExportedFunctionMarkers } from '@/workflow/workflow-steps/workflow-actions/utils/getWrongExportedFunctionMarkers';
+
+describe('getWrongExportedFunctionMarkers', () => {
+  it('should return marker when no exported function', () => {
+    const value = 'const main = async () => {}';
+    const result = getWrongExportedFunctionMarkers(value);
+    expect(result.length).toEqual(1);
+    expect(result[0].message).toEqual(
+      'An exported "main" arrow function is required.',
+    );
+  });
+
+  it('should return marker when no wrong exported function', () => {
+    const value = 'export const wrongMain = async () => {}';
+    const result = getWrongExportedFunctionMarkers(value);
+    expect(result.length).toEqual(1);
+  });
+
+  it('should return no marker when valid exported function', () => {
+    const value = 'export const main = async () => {}';
+    const result = getWrongExportedFunctionMarkers(value);
+    expect(result.length).toEqual(0);
+  });
+
+  it('should return handle multiple spaces', () => {
+    const value = 'export   const   main  = async () => {}';
+    const result = getWrongExportedFunctionMarkers(value);
+    expect(result.length).toEqual(0);
+  });
+});

packages/twenty-front/src/modules/workflow/workflow-steps/workflow-actions/utils/getWrongExportedFunctionMarkers.ts

@@ -0,0 +1,60 @@
+import { isDefined } from 'twenty-ui';
+
+const getSubstringCoordinate = (
+  text: string,
+  substring: string,
+): { line: number; column: number } | null => {
+  const lines = text.split('\n');
+
+  for (let lineIndex = 0; lineIndex < lines.length; lineIndex++) {
+    const columnIndex = lines[lineIndex].indexOf(substring);
+    if (columnIndex !== -1) {
+      return {
+        line: lineIndex + 1, // 1-based line number
+        column: columnIndex + 1, // 1-based column number
+      };
+    }
+  }
+
+  return null;
+};
+
+export const getWrongExportedFunctionMarkers = (value: string) => {
+  const validRegex = /export\s+const\s+main\s*=/g;
+  const invalidRegex = /export\s+const\s+\S*/g;
+  const exportRegex = /export\s+const/g;
+  const validMatch = value.match(validRegex);
+  const invalidMatch = value.match(invalidRegex);
+  const exportMatch = value.match(exportRegex);
+  const markers = [];
+
+  if (!validMatch && !!invalidMatch) {
+    const coordinates = getSubstringCoordinate(value, invalidMatch[0]);
+    if (isDefined(coordinates)) {
+      const endColumn = invalidMatch[0].length + coordinates.column;
+      markers.push({
+        severity: 8, //MarkerSeverity.Error,
+        message: 'Exported arrow function should be named "main"',
+        code: 'export const main',
+        startLineNumber: coordinates.line,
+        startColumn: coordinates.column,
+        endLineNumber: 1,
+        endColumn,
+      });
+    }
+  }
+
+  if (!exportMatch) {
+    markers.push({
+      severity: 8, //MarkerSeverity.Error,
+      message: 'An exported "main" arrow function is required.',
+      code: 'export const main',
+      startLineNumber: 1,
+      startColumn: 1,
+      endLineNumber: 1,
+      endColumn: 1,
+    });
+  }
+
+  return markers;
+};