fix(grid): preserve null text during editing

apps/desktop/src/lib/__tests__/dataGrid/dataGridCellCoercion.spec.ts

@@ -34,6 +34,26 @@ describe("dataGridCellDisplayText", () => {
 });
 
 describe("coerceDataGridCellValue", () => {
+  it.each(["null", "NULL", "Null", "nUlL"])("preserves literal %s input as text", (value) => {
+    expect(
+      coerceDataGridCellValue({
+        value,
+        oldValue: null,
+        databaseType: "mysql",
+        columnInfo: { data_type: "varchar(255)" },
+      }),
+    ).toBe(value);
+
+    expect(
+      coerceDataGridCellValue({
+        value,
+        oldValue: "previous",
+        databaseType: "postgres",
+        columnInfo: { data_type: "text" },
+      }),
+    ).toBe(value);
+  });
+
   it("preserves an explicitly generated empty string for a null cell", () => {
     const options = {
       value: "",

apps/desktop/src/lib/dataGrid/dataGridCellCoercion.ts

@@ -11,7 +11,6 @@ export interface CoerceDataGridCellValueOptions {
 
 export function coerceDataGridCellValue(options: CoerceDataGridCellValueOptions): GridCellValue {
   const { value, oldValue } = options;
-  if (value.toUpperCase() === "NULL") return null;
   if (value === "" && oldValue === null && !options.preserveEmptyString) return null;
   const postgresArrayValue = coercePostgresArrayValue(options);
   if (postgresArrayValue !== undefined) return postgresArrayValue;