fix: Dropdown not auto adjust placement (#34390)

components/dropdown/__tests__/index.test.js

@@ -79,4 +79,24 @@ describe('Dropdown', () => {
       expect.stringContaining("[antd: Dropdown] You are using 'topCenter'"),
     );
   });
+
+  // zombieJ: when replaced with react test lib, it may be mock fully content
+  it('dropdown should support auto adjust placement', () => {
+    const wrapper = mount(
+      <Dropdown overlay={<div>menu</div>} visible>
+        <button type="button">button</button>
+      </Dropdown>,
+    );
+
+    expect(wrapper.find('Trigger').prop('builtinPlacements')).toEqual(
+      expect.objectContaining({
+        bottomLeft: expect.objectContaining({
+          overflow: {
+            adjustX: 1,
+            adjustY: 1,
+          },
+        }),
+      }),
+    );
+  });
 });

components/dropdown/dropdown.tsx

@@ -189,6 +189,7 @@ const Dropdown: DropdownInterface = props => {
 
   const builtinPlacements = getPlacements({
     arrowPointAtCenter: typeof arrow === 'object' && arrow.pointAtCenter,
+    autoAdjustOverflow: true,
   });
 
   return (