[react-interactions] Ensure blur to window disengages press (#18125)

packages/react-interactions/events/src/dom/PressLegacy.js

@@ -126,6 +126,7 @@ const rootEventTypes = hasPointerEvents
       'click',
       'keyup',
       'scroll',
+      'blur',
     ]
   : [
       'click',
@@ -138,6 +139,7 @@ const rootEventTypes = hasPointerEvents
       'dragstart',
       'mouseup_active',
       'touchend',
+      'blur',
     ];
 
 function isFunction(obj): boolean {
@@ -881,6 +883,21 @@ const pressResponderImpl = {
       case 'touchcancel':
       case 'dragstart': {
         dispatchCancel(event, context, props, state);
+        break;
+      }
+      case 'blur': {
+        // If we encounter a blur event that moves focus to
+        // the window, then the relatedTarget will be null.
+        // In this case, we should cancel the active press.
+        // Alternatively, if the blur target matches the
+        // current pressed target, we should also cancel
+        // the active press.
+        if (
+          isPressed &&
+          (nativeEvent.relatedTarget === null || target === state.pressTarget)
+        ) {
+          dispatchCancel(event, context, props, state);
+        }
       }
     }
   },

packages/react-interactions/events/src/dom/__tests__/PressLegacy-test.internal.js

@@ -1167,4 +1167,27 @@ describe.each(environmentTable)('Press responder', hasPointerEvents => {
     expect(onPressStart).toBeCalled();
     expect(onPressEnd).toBeCalled();
   });
+
+  it('focus moving to the window should stop the press', () => {
+    const onPress = jest.fn(e => e.preventDefault());
+    const onPressStart = jest.fn(e => e.preventDefault());
+    const onPressEnd = jest.fn(e => e.preventDefault());
+    const buttonRef = React.createRef();
+
+    const Component = () => {
+      const listener = usePress({onPress, onPressStart, onPressEnd});
+      return <button ref={buttonRef} DEPRECATED_flareListeners={listener} />;
+    };
+    ReactDOM.render(<Component />, container);
+
+    const target = createEventTarget(buttonRef.current);
+    target.pointerdown();
+    const secondTarget = createEventTarget(document);
+    // relatedTarget is null when moving focus to window
+    expect(onPressStart).toBeCalled();
+    secondTarget.blur({relatedTarget: null});
+    expect(onPressEnd).toBeCalled();
+    target.pointerup();
+    expect(onPress).not.toBeCalled();
+  });
 });