fix: Collapse not working using custom component as panel

src/Collapse.tsx

@@ -4,7 +4,7 @@ import classNames from 'classnames';
 import shallowEqual from 'shallowequal';
 import toArray from 'rc-util/lib/Children/toArray';
 import CollapsePanel from './Panel';
-import { CollapseProps, CollapsibleType } from './interface';
+import type { CollapseProps, CollapsibleType } from './interface';
 
 function getActiveKeysArray(activeKey: React.Key | React.Key[]) {
   let currentActiveKey = activeKey;
@@ -78,18 +78,30 @@ class Collapse extends React.Component<CollapseProps, CollapseState> {
     if (!child) return null;
 
     const { activeKey } = this.state;
-    const { prefixCls, openMotion, accordion, destroyInactivePanel: rootDestroyInactivePanel, expandIcon, collapsible } = this.props;
+    const {
+      prefixCls,
+      openMotion,
+      accordion,
+      destroyInactivePanel: rootDestroyInactivePanel,
+      expandIcon,
+      collapsible,
+    } = this.props;
     // If there is no key provide, use the panel order as default key
     const key = child.key || String(index);
-    const { header, headerClass, destroyInactivePanel, collapsible: childCollapsible } = child.props;
+    const {
+      header,
+      headerClass,
+      destroyInactivePanel,
+      collapsible: childCollapsible,
+    } = child.props;
     let isActive = false;
     if (accordion) {
       isActive = activeKey[0] === key;
     } else {
       isActive = activeKey.indexOf(key) > -1;
     }
 
-    const mergeCollapsible: CollapsibleType  = childCollapsible ?? collapsible;
+    const mergeCollapsible: CollapsibleType = childCollapsible ?? collapsible;
 
     const props = {
       key,
@@ -112,6 +124,12 @@ class Collapse extends React.Component<CollapseProps, CollapseState> {
       return child;
     }
 
+    Object.keys(props).forEach((propName: keyof typeof props) => {
+      if (typeof props[propName] === 'undefined') {
+        delete props[propName];
+      }
+    });
+
     return React.cloneElement(child, props);
   };
 

tests/index.spec.tsx

@@ -485,6 +485,34 @@ describe('collapse', () => {
     expect(collapse.find('.custom-child').getDOMNode().innerHTML).toBe('custom-child');
   });
 
+  // https://github.com/ant-design/ant-design/issues/36327
+  // https://github.com/ant-design/ant-design/issues/6179
+  // https://github.com/react-component/collapse/issues/73#issuecomment-323626120
+  it('should support custom component', () => {
+    const PanelElement = (props) => (
+      <Panel header="collapse 1" {...props}>
+        <p>test</p>
+      </Panel>
+    );
+    const collapse = mount(
+      <Collapse defaultActiveKey="1">
+        <PanelElement key="1" />
+        <Panel header="collapse 2" key="2">
+          second
+        </Panel>
+      </Collapse>,
+    );
+    expect(collapse.find('.rc-collapse-content-active').length).toBe(1);
+    expect(collapse.find('.rc-collapse-content').hasClass('rc-collapse-content-active')).toBe(true);
+    expect(collapse.find('.rc-collapse-header').at(0).text()).toBe('collapse 1');
+    expect(collapse.find('.rc-collapse-header').at(0).find('.arrow').length).toBe(1);
+    collapse.find('.rc-collapse-header').at(0).simulate('click');
+    expect(collapse.find('.rc-collapse-content-active').length).toBe(0);
+    expect(collapse.find('.rc-collapse-content').hasClass('rc-collapse-content-inactive')).toBe(
+      true,
+    );
+  });
+
   describe('collapsible', () => {
     it('default', () => {
       const collapse = mount(