fix(grid): copy NULL cells as empty fields

apps/desktop/src/composables/__tests__/useDataGridExport.spec.ts

@@ -730,6 +730,66 @@ describe("useDataGridExport prepared row statements", () => {
     expect(copyToClipboard).toHaveBeenCalledWith(text);
   });
 
+  it("copies a NULL cell as an empty clipboard value", async () => {
+    const state = createExportState(editableTable, ["id", "name"], undefined, [1, null], undefined, undefined, [], DEFAULT_DATA_GRID_EXTRACTOR_OPTIONS, false, undefined, false, 1, 1);
+
+    await state.copyCell();
+
+    expect(copyToClipboard).toHaveBeenCalledWith("");
+  });
+
+  it("copies all rows with empty fields for NULL cells", async () => {
+    const text = "id\tname\n1\t\n2\tAda";
+    const state = createExportState(editableTable, ["id", "name"], undefined, undefined, undefined, [
+      [1, null],
+      [2, "Ada"],
+    ]);
+
+    await state.copyAll();
+
+    expect(copyToClipboard).toHaveBeenCalledWith(text);
+    expect(parseDataGridClipboard(text)).toEqual([
+      ["id", "name"],
+      ["1", null],
+      ["2", "Ada"],
+    ]);
+  });
+
+  it("copies a NULL smart single-cell selection as an empty value", async () => {
+    const matrix: CellSelectionMatrix = {
+      rowIndexes: [0],
+      columnIndexes: [1],
+      columns: ["name"],
+      rows: [[null]],
+    };
+    vi.mocked(extractDataGridSelection).mockResolvedValueOnce({ text: "", mimeType: "text/plain", fileExtension: "txt", rowCount: 1, columnCount: 1 });
+    const state = createExportState(editableTable, ["id", "name"], matrix, [1, null]);
+
+    await expect(state.copyWithPreference("smart")).resolves.toBe(true);
+
+    expect(copyToClipboard).toHaveBeenCalledWith("");
+  });
+
+  it("uses an empty default NULL text for TSV clipboard output", async () => {
+    const matrix: CellSelectionMatrix = {
+      rowIndexes: [0],
+      columnIndexes: [0, 1],
+      columns: ["id", "name"],
+      rows: [[1, null]],
+    };
+    vi.mocked(extractDataGridSelection).mockResolvedValueOnce({ text: "1\t", mimeType: "text/tab-separated-values", fileExtension: "tsv", rowCount: 1, columnCount: 2 });
+    const state = createExportState(editableTable, ["id", "name"], matrix, [1, null]);
+
+    await expect(state.copyWithExtractor("tsv")).resolves.toBe(true);
+
+    expect(extractDataGridSelection).toHaveBeenCalledWith(
+      expect.objectContaining({
+        options: expect.objectContaining({ dsv: expect.objectContaining({ nullText: "" }) }),
+      }),
+    );
+    expect(copyToClipboard).toHaveBeenCalledWith("1\t");
+  });
+
   it("preserves JSON-column text in a single-cell smart copy", async () => {
     const tableMeta: DataGridTableMeta = {
       tableName: "events",

apps/desktop/src/composables/useDataGridExport.ts

@@ -8,7 +8,7 @@ import { type CellSelectionMatrix, type CellSelectionRange, type SelectionData }
 import type { DataGridExtractRequest, DataGridExtractorOptions } from "@/lib/dataGrid/dataGridCopyExtractor";
 import { useToast } from "@/composables/useToast";
 import { useExportTracker } from "@/composables/useExportTracker";
-import { displayCellValue, type CellValue } from "@/lib/dataGrid/cellValue";
+import { clipboardCellValue, type CellValue } from "@/lib/dataGrid/cellValue";
 import { tryStartExclusiveActivation, type ActionActivationGuard } from "@/lib/connection/actionActivation";
 import { copyToClipboard } from "@/lib/common/clipboard";
 import { clearDataGridClipboardCopy, rememberDataGridClipboardCopy } from "@/lib/dataGrid/dataGridClipboard";
@@ -529,7 +529,7 @@ export function useDataGridExport(options: UseDataGridExportOptions) {
     const sourceIndex = visibleColumnIndexes.value[contextCell.value.col] ?? contextCell.value.col;
     const [resolvedItem] = await resolveVisibleRowValues([item], [sourceIndex]);
     const val = resolvedItem?.data[contextCell.value.col] ?? null;
-    await copyText(displayCellValue(val), { rows: [[val]] });
+    await copyText(clipboardCellValue(val), { rows: [[val]] });
   }
 
   async function copyRow() {
@@ -671,10 +671,8 @@ export function useDataGridExport(options: UseDataGridExportOptions) {
   });
 
   async function copyAll() {
-    const header = columns.value.join("\t");
     const rows = (await resolveVisibleRowValues(displayItems.value.filter((item) => !item.isDraft))).map((item) => item.data);
-    const body = rows.map((row) => row.map((cell) => displayCellValue(cell)).join("\t")).join("\n");
-    await copyText(`${header}\n${body}`, { rows, header: columns.value });
+    await copyText(formatTsv(columns.value, rows), { rows, header: columns.value });
   }
 
   // --- Export functions ---

apps/desktop/src/composables/useDataGridExtractor.ts

@@ -329,7 +329,7 @@ export function useDataGridExtractor(options: UseDataGridExtractorOptions) {
       const request = await resolveRequestSourceValues(initialRequest);
       const mongoResult = await resolveMongoExtractorResult(extractor, request);
       const result = mongoResult ?? (await api.extractDataGridSelection(request));
-      if (!result.text) return false;
+      if (!result.text && !extractorAllowsEmptyOutput(extractor)) return false;
       // Derive the grid paste-back payload from the effective request schema so
       // hidden support columns, row headers, NULLs, tabs, and newlines keep the
       // same shape and values as the rendered raw text or TSV.
@@ -365,7 +365,7 @@ export function useDataGridExtractor(options: UseDataGridExtractorOptions) {
     const request = await resolveRequestSourceValues(initialRequest, previewRowCount);
     const mongoResult = await resolveMongoExtractorResult(extractor, request, previewRowCount);
     const result = mongoResult ?? (await api.extractDataGridSelection(request));
-    if (!result.text) throw new Error(t("grid.copyExtractorEmptySelection"));
+    if (!result.text && !extractorAllowsEmptyOutput(extractor)) throw new Error(t("grid.copyExtractorEmptySelection"));
     return { ...result, sourceRowCount, truncated: sourceRowCount > result.rowCount };
   }
 
@@ -396,6 +396,10 @@ export function useDataGridExtractor(options: UseDataGridExtractorOptions) {
   return { copyWithExtractor, copyWithPreference, previewWithExtractor, previewWithPreference, canCopyWithExtractor };
 }
 
+function extractorAllowsEmptyOutput(extractor: DataGridCopyExtractorId): boolean {
+  return DATA_GRID_COPY_EXTRACTOR_DESCRIPTORS[extractor].category === "raw" || DATA_GRID_COPY_EXTRACTOR_DESCRIPTORS[extractor].category === "delimited";
+}
+
 function compactTableMeta(tableMeta: DataGridTableMeta | undefined, requiredColumns: string[]): DataGridTableMeta | undefined {
   if (!tableMeta?.columns) return tableMeta;
   const requiredNames = new Set(requiredColumns.map(normalizeName));