fix(CSV export): update the csv export format for multi-select and arrray fields to match the import template format (#16450)

Closes #16432

Multi-Select and Array fields were exported in an incompatible format:
**Before**: {"0":"VALUE1","1":"VALUE2"} (object with numeric keys)
**After**: ["VALUE1","VALUE2"] (JSON array)

This prevented exported CSV files from being re-imported successfully.

### Changes
Modified useExportProcessRecordsForCSV hook to stringify Multi-Select
and Array fields as JSON arrays before CSV generation

---------

Co-authored-by: Etienne <45695613+etiennejouan@users.noreply.github.com>

packages/twenty-front/src/modules/object-record/object-options-dropdown/hooks/__tests__/useExportProcessRecordsForCSV.test.ts

@@ -9,6 +9,8 @@ jest.mock('@/object-metadata/hooks/useObjectMetadataItem', () => ({
       fields: [
         { type: FieldMetadataType.CURRENCY, name: 'price' },
         { type: FieldMetadataType.TEXT, name: 'name' },
+        { type: FieldMetadataType.MULTI_SELECT, name: 'tags' },
+        { type: FieldMetadataType.ARRAY, name: 'skills' },
       ],
     },
   })),
@@ -56,4 +58,82 @@ describe('useExportProcessRecordsForCSV', () => {
       },
     ]);
   });
+
+  it('processes records with multi-select and array fields correctly', () => {
+    const { result } = renderHook(() =>
+      useExportProcessRecordsForCSV('someObject'),
+    );
+
+    const records = [
+      {
+        __typename: 'ObjectRecord',
+        id: '1',
+        tags: ['TAG1', 'TAG2'],
+        skills: ['skill1', 'skill2', 'skill3'],
+        name: 'Item 1',
+      },
+      {
+        __typename: 'ObjectRecord',
+        id: '2',
+        tags: ['TAG3'],
+        skills: ['skill4'],
+        name: 'Item 2',
+      },
+    ];
+
+    let processedRecords;
+
+    act(() => {
+      processedRecords = result.current.processRecordsForCSVExport(records);
+    });
+
+    expect(processedRecords).toEqual([
+      {
+        __typename: 'ObjectRecord',
+        id: '1',
+        tags: '["TAG1","TAG2"]',
+        skills: '["skill1","skill2","skill3"]',
+        name: 'Item 1',
+      },
+      {
+        __typename: 'ObjectRecord',
+        id: '2',
+        tags: '["TAG3"]',
+        skills: '["skill4"]',
+        name: 'Item 2',
+      },
+    ]);
+  });
+
+  it('processes records with empty multi-select and array fields correctly', () => {
+    const { result } = renderHook(() =>
+      useExportProcessRecordsForCSV('someObject'),
+    );
+
+    const records = [
+      {
+        __typename: 'ObjectRecord',
+        id: '1',
+        tags: [],
+        skills: [],
+        name: 'Item 1',
+      },
+    ];
+
+    let processedRecords;
+
+    act(() => {
+      processedRecords = result.current.processRecordsForCSVExport(records);
+    });
+
+    expect(processedRecords).toEqual([
+      {
+        __typename: 'ObjectRecord',
+        id: '1',
+        tags: '[]',
+        skills: '[]',
+        name: 'Item 1',
+      },
+    ]);
+  });
 });

packages/twenty-front/src/modules/object-record/object-options-dropdown/hooks/useExportProcessRecordsForCSV.ts

@@ -29,6 +29,8 @@ export const useExportProcessRecordsForCSV = (objectNameSingular: string) => {
                   currencyCode: record[field.name].currencyCode,
                 } satisfies FieldCurrencyValue,
               };
+            case FieldMetadataType.MULTI_SELECT:
+            case FieldMetadataType.ARRAY:
             case FieldMetadataType.RAW_JSON:
               return {
                 ...processedRecord,

packages/twenty-front/src/modules/object-record/record-index/export/hooks/__tests__/useRecordIndexExportRecords.test.ts

@@ -67,6 +67,105 @@ describe('generateCsv', () => {
 1,some field,,https://www.test.com,"[{""label"":""secondary link 1"",""url"":""https://www.test.com""},{""label"":""secondary link 2"",""url"":""https://www.test.com""}]",a relation`);
   });
 
+  it('generates csv with multi-select and array fields as JSON arrays', () => {
+    const columns: Pick<
+      ColumnDefinition<FieldMetadata>,
+      'size' | 'label' | 'type' | 'metadata'
+    >[] = [
+      {
+        label: 'Name',
+        size: 100,
+        type: FieldMetadataType.TEXT,
+        metadata: { fieldName: 'name' },
+      },
+      {
+        label: 'Tags',
+        size: 120,
+        type: FieldMetadataType.MULTI_SELECT,
+        metadata: { fieldName: 'tags' },
+      },
+      {
+        label: 'Skills',
+        size: 150,
+        type: FieldMetadataType.ARRAY,
+        metadata: { fieldName: 'skills' },
+      },
+    ];
+
+    const rows = [
+      {
+        id: '1',
+        name: 'John Doe',
+        tags: '["DISTRIBUTOR","IMPLEMENTATION"]',
+        skills: '["JavaScript","TypeScript","React"]',
+      },
+      {
+        id: '2',
+        name: 'Jane Smith',
+        tags: '["PARTNER"]',
+        skills: '["Python","Django"]',
+      },
+    ];
+
+    const csv = generateCsv({ columns, rows });
+
+    expect(csv).toContain('[""DISTRIBUTOR"",""IMPLEMENTATION""]');
+    expect(csv).toContain('[""JavaScript"",""TypeScript"",""React""]');
+    expect(csv).toContain('[""PARTNER""]');
+    expect(csv).toContain('[""Python"",""Django""]');
+
+    expect(csv).not.toContain('{"0":"DISTRIBUTOR","1":"IMPLEMENTATION"}');
+    expect(csv).not.toContain(
+      '{"0":"JavaScript","1":"TypeScript","2":"React"}',
+    );
+
+    expect(csv).toContain('Id,Name,Tags,Skills');
+    expect(csv).toContain('1,John Doe');
+    expect(csv).toContain('2,Jane Smith');
+  });
+
+  it('generates csv with empty multi-select and array fields as empty JSON arrays', () => {
+    const columns: Pick<
+      ColumnDefinition<FieldMetadata>,
+      'size' | 'label' | 'type' | 'metadata'
+    >[] = [
+      {
+        label: 'Name',
+        size: 100,
+        type: FieldMetadataType.TEXT,
+        metadata: { fieldName: 'name' },
+      },
+      {
+        label: 'Tags',
+        size: 120,
+        type: FieldMetadataType.MULTI_SELECT,
+        metadata: { fieldName: 'tags' },
+      },
+      {
+        label: 'Skills',
+        size: 150,
+        type: FieldMetadataType.ARRAY,
+        metadata: { fieldName: 'skills' },
+      },
+    ];
+
+    const rows = [
+      {
+        id: '1',
+        name: 'John Doe',
+        tags: '[]',
+        skills: '[]',
+      },
+    ];
+
+    const csv = generateCsv({ columns, rows });
+
+    expect(csv).toContain('[]');
+
+    expect(csv).toContain('Id,Name,Tags,Skills');
+    expect(csv).toContain('1,John Doe,[],[]');
+  });
+
   describe('CSV Injection Prevention with ZWJ', () => {
     it('prevents formula injection with equals sign using ZWJ prefix', () => {
       const columns: Pick<

packages/twenty-front/src/modules/object-record/record-index/export/hooks/useExportProcessRecordsForCSV.ts

@@ -1,39 +0,0 @@
-import { useObjectMetadataItem } from '@/object-metadata/hooks/useObjectMetadataItem';
-import { type FieldCurrencyValue } from '@/object-record/record-field/ui/types/FieldMetadata';
-import { type ObjectRecord } from '@/object-record/types/ObjectRecord';
-import { isDefined } from 'twenty-shared/utils';
-import { FieldMetadataType } from '~/generated-metadata/graphql';
-import { convertCurrencyMicrosToCurrencyAmount } from '~/utils/convertCurrencyToCurrencyMicros';
-
-export const useExportProcessRecordsForCSV = (objectNameSingular: string) => {
-  const { objectMetadataItem } = useObjectMetadataItem({
-    objectNameSingular,
-  });
-
-  const processRecordsForCSVExport = (records: ObjectRecord[]) => {
-    return records.map((record) => {
-      const currencyFields = objectMetadataItem.fields.filter(
-        (field) => field.type === FieldMetadataType.CURRENCY,
-      );
-
-      const processedRecord = {
-        ...record,
-      };
-
-      for (const currencyField of currencyFields) {
-        if (isDefined(record[currencyField.name])) {
-          processedRecord[currencyField.name] = {
-            amountMicros: convertCurrencyMicrosToCurrencyAmount(
-              record[currencyField.name].amountMicros,
-            ),
-            currencyCode: record[currencyField.name].currencyCode,
-          } satisfies FieldCurrencyValue;
-        }
-      }
-
-      return processedRecord;
-    });
-  };
-
-  return { processRecordsForCSVExport };
-};