Switching the name property preserves radio selection

Fixes a case where changing the name and checked value of a radio button in the same update would lead to checking the wrong radio input. Also adds a DOM test fixture for related issue.

Related issues:
https://github.com/facebook/react/issues/7630

fixtures/dom/src/components/fixtures/input-change-events/RadioNameChangeFixture.js

@@ -0,0 +1,46 @@
+const React = window.React;
+const noop = n => n;
+
+class RadioNameChangeFixture extends React.Component {
+  state = {
+    updated: false,
+  };
+  onClick = () => {
+    this.setState(state => {
+      return {updated: !state.updated};
+    });
+  };
+  render() {
+    const {updated} = this.state;
+    const radioName = updated ? 'firstName' : 'secondName';
+    return (
+      <div>
+        <label>
+          <input
+            type="radio"
+            name={radioName}
+            onChange={noop}
+            checked={updated === true}
+          />
+          First Radio
+        </label>
+
+        <label>
+          <input
+            type="radio"
+            name={radioName}
+            onChange={noop}
+            checked={updated === false}
+          />
+          Second Radio
+        </label>
+
+        <div>
+          <button type="button" onClick={this.onClick}>Toggle</button>
+        </div>
+      </div>
+    );
+  }
+}
+
+export default RadioNameChangeFixture;

fixtures/dom/src/components/fixtures/input-change-events/index.js

@@ -3,6 +3,7 @@ import TestCase from '../../TestCase';
 import RangeKeyboardFixture from './RangeKeyboardFixture';
 import RadioClickFixture from './RadioClickFixture';
 import RadioGroupFixture from './RadioGroupFixture';
+import RadioNameChangeFixture from './RadioNameChangeFixture';
 import InputPlaceholderFixture from './InputPlaceholderFixture';
 const React = window.React;
 
@@ -88,6 +89,24 @@ class InputChangeEvents extends React.Component {
 
           <InputPlaceholderFixture />
         </TestCase>
+        <TestCase
+          title="Radio button groups with name changes"
+          description={`
+            A radio button group should have correct checked value when
+            the names changes
+          `}
+          resolvedBy="#11227"
+          affectedBrowsers="IE9+">
+          <TestCase.Steps>
+            <li>Click the toggle button</li>
+          </TestCase.Steps>
+
+          <TestCase.ExpectedResult>
+            The checked radio button should switch between the first and second radio button
+          </TestCase.ExpectedResult>
+
+          <RadioNameChangeFixture />
+        </TestCase>
       </FixtureSet>
     );
   }

packages/react-dom/src/__tests__/ReactDOMInput-test.js

@@ -668,6 +668,45 @@ describe('ReactDOMInput', () => {
     expect(cNode.checked).toBe(true);
   });
 
+  it('should check the correct radio when the selected name moves', () => {
+    class App extends React.Component {
+      state = {
+        updated: false,
+      };
+      onClick = () => {
+        this.setState({updated: true});
+      };
+      render() {
+        const {updated} = this.state;
+        const radioName = updated ? 'secondName' : 'firstName';
+        return (
+          <div>
+            <button type="button" onClick={this.onClick} />
+            <input
+              type="radio"
+              name={radioName}
+              onChange={emptyFunction}
+              checked={updated === true}
+            />
+            <input
+              type="radio"
+              name={radioName}
+              onChange={emptyFunction}
+              checked={updated === false}
+            />
+          </div>
+        );
+      }
+    }
+
+    var stub = ReactTestUtils.renderIntoDocument(<App />);
+    var buttonNode = ReactDOM.findDOMNode(stub).childNodes[0];
+    var firstRadioNode = ReactDOM.findDOMNode(stub).childNodes[1];
+    expect(firstRadioNode.checked).toBe(false);
+    ReactTestUtils.Simulate.click(buttonNode);
+    expect(firstRadioNode.checked).toBe(true);
+  });
+
   it('should control radio buttons if the tree updates during render', () => {
     var sharedParent = document.createElement('div');
     var container1 = document.createElement('div');

packages/react-dom/src/client/ReactDOMFiberComponent.js

@@ -764,6 +764,17 @@ export function updateProperties(
   lastRawProps: Object,
   nextRawProps: Object,
 ): void {
+  // Update checked *before* name.
+  // In the middle of an update, it is possible to have multiple checked.
+  // When a checked radio tries to change name, browser makes another radio's checked false.
+  if (
+    tag === 'input' &&
+    nextRawProps.type === 'radio' &&
+    nextRawProps.name != null
+  ) {
+    ReactDOMFiberInput.updateChecked(domElement, nextRawProps);
+  }
+
   var wasCustomComponentTag = isCustomComponent(tag, lastRawProps);
   var isCustomComponentTag = isCustomComponent(tag, nextRawProps);
   // Apply the diff.

packages/react-dom/src/client/ReactDOMFiberInput.js

@@ -142,6 +142,14 @@ export function initWrapperState(element: Element, props: Object) {
   };
 }
 
+export function updateChecked(element: Element, props: Object) {
+  var node = ((element: any): InputWithWrapperState);
+  var checked = props.checked;
+  if (checked != null) {
+    DOMPropertyOperations.setValueForProperty(node, 'checked', checked);
+  }
+}
+
 export function updateWrapper(element: Element, props: Object) {
   var node = ((element: any): InputWithWrapperState);
   if (__DEV__) {
@@ -181,14 +189,7 @@ export function updateWrapper(element: Element, props: Object) {
     }
   }
 
-  var checked = props.checked;
-  if (checked != null) {
-    DOMPropertyOperations.setValueForProperty(
-      node,
-      'checked',
-      checked || false,
-    );
-  }
+  updateChecked(element, props);
 
   var value = props.value;
   if (value != null) {