[tooltip] Prevent stuck-open tooltip when child becomes disabled

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

@@ -357,6 +357,9 @@ const Tooltip = React.forwardRef(function Tooltip(inProps, ref) {
   );
 
   const handleMouseOver = (event) => {
+    if (childNode?.disabled) {
+      return;
+    }
     if (ignoreNonTouchEvents.current && event.type !== 'touchstart') {
       return;
     }

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

@@ -1132,6 +1132,53 @@ describe('<Tooltip />', () => {
       expect(handleClose.callCount).to.equal(1);
     });
 
+    it('stays closed when a stray mouseover lands while the disabled child is closing', async () => {
+      // Deterministic regression test for the flaky "stuck open" tooltip:
+      // when the focused child becomes disabled the close is scheduled via the React
+      // #9142 native-blur workaround, but a layout-shift `mouseover` on the interactive
+      // popper used to cancel that pending close and reopen the tooltip. A disabled
+      // anchor must never (re)open. `leaveDelay` opens a deterministic window in which to
+      // dispatch the stray `mouseover` before the close fires.
+      clock.restore();
+      const handleClose = spy();
+
+      function TestCase() {
+        const [disabled, setDisabled] = React.useState(false);
+        return (
+          <Tooltip
+            enterDelay={0}
+            leaveDelay={100}
+            onClose={handleClose}
+            title="Some information"
+            slotProps={{ transition: { timeout: 0 } }}
+          >
+            <button disabled={disabled} onClick={() => setDisabled(true)}>
+              Disable
+            </button>
+          </Tooltip>
+        );
+      }
+
+      const { user } = render(<TestCase />);
+
+      await user.tab();
+      await waitFor(() => {
+        expect(screen.getByRole('tooltip')).toBeVisible();
+      });
+
+      // Disabling the focused child schedules the close (leaveDelay window still pending).
+      await user.keyboard('{Enter}');
+
+      // A stray `mouseover` reaches the interactive popper before the close fires.
+      fireEvent.mouseOver(screen.getByRole('tooltip'));
+
+      // The disabled anchor must still close (and not reopen).
+      await waitFor(() => {
+        expect(screen.queryByRole('tooltip')).to.equal(null);
+      });
+      expect(handleClose.callCount).to.equal(1);
+    });
+
     it('closes on blur', async () => {
       const eventLog = [];
       const transitionTimeout = 0;