[checkbox group] Fix parent checkbox with custom validate fn (#4912)

packages/react/src/checkbox-group/CheckboxGroup.test.tsx

@@ -326,6 +326,30 @@ describe('<CheckboxGroup />', () => {
       checkboxes.forEach((checkbox) => expect(checkbox).toHaveAttribute('aria-invalid', 'true'));
     });
 
+    it('validates with the group value when toggling the parent checkbox', async () => {
+      const validateSpy = vi.fn((_value: unknown) => null);
+
+      const { user } = render(
+        <Field.Root validationMode="onChange" validate={validateSpy} name="fruits">
+          <CheckboxGroup allValues={['apple', 'orange']}>
+            <Checkbox.Root parent data-testid="parent" />
+            <Checkbox.Root value="apple" />
+            <Checkbox.Root value="orange" />
+          </CheckboxGroup>
+        </Field.Root>,
+      );
+
+      const parent = screen.getByTestId('parent');
+
+      await user.click(parent);
+      expect(validateSpy).toHaveBeenCalledTimes(1);
+      expect(validateSpy.mock.lastCall?.[0]).toEqual(['apple', 'orange']);
+
+      await user.click(parent);
+      expect(validateSpy).toHaveBeenCalledTimes(2);
+      expect(validateSpy.mock.lastCall?.[0]).toEqual([]);
+    });
+
     it('revalidates when the controlled value changes externally', async () => {
       const validateSpy = vi.fn((value: unknown) => {
         const values = value as string[];

packages/react/src/checkbox/root/CheckboxRoot.tsx

@@ -191,7 +191,7 @@ export const CheckboxRoot = React.forwardRef(function CheckboxRoot(
   }, [checked, groupIndeterminate, setFilled]);
 
   useValueChanged(checked, () => {
-    if (groupContext && !parent) {
+    if (groupContext) {
       return;
     }