[Button] Fix running formAction when passed

packages/mui-material/src/ButtonBase/ButtonBase.js

@@ -257,7 +257,10 @@ const ButtonBase = React.forwardRef(function ButtonBase(inProps, ref) {
 
   const buttonProps = {};
   if (ComponentProp === 'button') {
-    buttonProps.type = type === undefined ? 'button' : type;
+    const hasFormAttributes = !!other.formAction;
+    // ButtonBase was defaulting to type="button" when no type prop was provided, which prevented form submission and broke formAction functionality.
+    // The fix checks for form-related attributes and skips the default type to allow the browser's natural submit behavior (type="submit").
+    buttonProps.type = type === undefined && !hasFormAttributes ? 'button' : type;
     buttonProps.disabled = disabled;
   } else {
     if (!other.href && !other.to) {
@@ -395,6 +398,10 @@ ButtonBase.propTypes /* remove-proptypes */ = {
    * if needed.
    */
   focusVisibleClassName: PropTypes.string,
+  /**
+   * @ignore
+   */
+  formAction: PropTypes.oneOfType([PropTypes.func, PropTypes.string]),
   /**
    * @ignore
    */

packages/mui-material/src/ButtonBase/ButtonBase.test.js

@@ -1294,4 +1294,26 @@ describe('<ButtonBase />', () => {
       expect(ref.current).not.to.equal(null);
     });
   });
+
+  describe('form attributes', () => {
+    it('should not set default type when formAction is present', async function test() {
+      if (window.navigator.userAgent.includes('jsdom')) {
+        this.skip();
+      }
+
+      const formActionSpy = spy();
+      const { user } = render(
+        <form>
+          <ButtonBase formAction={formActionSpy}>Submit</ButtonBase>
+        </form>,
+      );
+      const button = screen.getByRole('button');
+
+      // Should not have type="button" when formAction is present
+      expect(button).not.to.have.attribute('type', 'button');
+      expect(button).to.have.attribute('formaction');
+      await user.click(button);
+      expect(formActionSpy.callCount).to.equal(1);
+    });
+  });
 });