[UnstyledButton] Add disabled attribute to UnstyledButton

.changeset/forty-cars-shake.md

@@ -0,0 +1,5 @@
+---
+'@shopify/polaris': patch
+---
+
+Adds the `disabled` attribute to disabled `UnstyledButton` components to prevent them from being inadvertently selected by `button:not(:disabled)` CSS selectors.

polaris-react/src/components/UnstyledButton/UnstyledButton.tsx

@@ -81,6 +81,7 @@ export function UnstyledButton({
       <button
         {...interactiveProps}
         aria-disabled={disabled}
+        disabled={disabled}
         type={submit ? 'submit' : 'button'}
         aria-busy={loading ? true : undefined}
         aria-controls={ariaControls}

polaris-react/src/components/UnstyledButton/tests/UnstyledButton.test.tsx

@@ -213,6 +213,7 @@ describe('<Button />', () => {
       const button = mountWithApp(<UnstyledButton disabled />);
       expect(button).toContainReactComponent('button', {
         'aria-disabled': true,
+        disabled: true,
       });
     });