Fix: required validation for multi-select ComboBox (#9788)

packages/@react-aria/combobox/src/useComboBox.ts

@@ -218,6 +218,8 @@ export function useComboBox<T, M extends SelectionMode = 'single'>(props: AriaCo
   let {isInvalid, validationErrors, validationDetails} = state.displayValidation;
   let {labelProps, inputProps, descriptionProps, errorMessageProps} = useTextField({
     ...props,
+    // In multi-select mode, only set required if the selection is empty.
+    isRequired: props.selectionMode === 'multiple' ? props.isRequired && state.selectionManager.isEmpty : props.isRequired,
     onChange: state.setInputValue,
     onKeyDown: !isReadOnly ? chain(state.isOpen && collectionProps.onKeyDown, onKeyDown, props.onKeyDown) : props.onKeyDown,
     onBlur,

packages/@react-stately/combobox/src/useComboBoxState.ts

@@ -481,10 +481,10 @@ export function useComboBoxState<T extends object, M extends SelectionMode = 'si
     }
   };
 
-  let valueOnFocus = useRef(inputValue);
+  let valueOnFocus = useRef([inputValue, displayValue]);
   let setFocused = (isFocused: boolean) => {
     if (isFocused) {
-      valueOnFocus.current = inputValue;
+      valueOnFocus.current = [inputValue, displayValue];
       if (menuTrigger === 'focus' && !props.isReadOnly) {
         open(null, 'focus');
       }
@@ -493,7 +493,8 @@ export function useComboBoxState<T extends object, M extends SelectionMode = 'si
         commitValue();
       }
 
-      if (inputValue !== valueOnFocus.current) {
+      // Commit validation if the input value or selected items changed.
+      if (inputValue !== valueOnFocus.current[0] || displayValue !== valueOnFocus.current[1]) {
         validation.commitValidation();
       }
     }

packages/react-aria-components/test/ComboBox.test.js

@@ -819,6 +819,62 @@ describe('ComboBox', () => {
     expect(onChange).toHaveBeenLastCalledWith(['1']);
   });
 
+  it('should support isRequired with multiple selection', async () => {
+    let {container, getByTestId} = render(
+      <Form data-testid="form">
+        <ComboBox name="combobox" selectionMode="multiple" isRequired>
+          <Label>Favorite Animal</Label>
+          <Input />
+          <Button />
+          <FieldError />
+          <Popover>
+            <ListBox>
+              <ListBoxItem id="1">Cat</ListBoxItem>
+              <ListBoxItem id="2">Dog</ListBoxItem>
+              <ListBoxItem id="3">Kangaroo</ListBoxItem>
+            </ListBox>
+          </Popover>
+        </ComboBox>
+      </Form>
+    );
+    let comboboxTester = testUtilUser.createTester('ComboBox', {root: container});
+    let combobox = comboboxTester.combobox;
+
+    expect(combobox).toHaveAttribute('required');
+    expect(combobox.validity.valid).toBe(false);
+
+    act(() => {getByTestId('form').checkValidity();});
+    expect(combobox).toHaveAttribute('aria-describedby');
+    expect(container.querySelector('.react-aria-ComboBox')).toHaveAttribute('data-invalid');
+
+    await comboboxTester.open();
+    let options = comboboxTester.options();
+    await user.click(options[0]);
+
+    act(() => combobox.blur());
+    expect(combobox).not.toHaveAttribute('required');
+    expect(combobox.validity.valid).toBe(true);
+    expect(container.querySelector('.react-aria-ComboBox')).not.toHaveAttribute('data-invalid');
+
+    let hiddenInputs = container.querySelectorAll('input[type="hidden"]');
+    expect(hiddenInputs).toHaveLength(1);
+    expect(hiddenInputs[0]).toHaveAttribute('name', 'combobox');
+    expect(hiddenInputs[0]).toHaveAttribute('value', '1');
+
+    await comboboxTester.open();
+    options = comboboxTester.options();
+    await user.click(options[0]);
+    act(() => combobox.blur());
+    expect(combobox).toHaveAttribute('required');
+    expect(combobox.validity.valid).toBe(false);
+    expect(combobox).toHaveAttribute('aria-describedby');
+
+    hiddenInputs = container.querySelectorAll('input[type="hidden"]');
+    expect(hiddenInputs).toHaveLength(1);
+    expect(hiddenInputs[0]).toHaveAttribute('name', 'combobox');
+    expect(hiddenInputs[0]).toHaveAttribute('value', '');
+  });
+
   it('should not close the combobox when clicking on the input', async () => {
     let onOpenChange = jest.fn();
     let {container, getByRole} = render(<TestComboBox onOpenChange={onOpenChange} />);