test(getComponentName): Increase test coverage (#18149)

Co-authored-by: Brian Vaughn <brian.david.vaughn@gmail.com>

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

@@ -542,7 +542,7 @@ describe('ReactCompositeComponent', () => {
   });
 
   it('should warn when shouldComponentUpdate() returns undefined', () => {
-    class Component extends React.Component {
+    class ClassComponent extends React.Component {
       state = {bogus: false};
 
       shouldComponentUpdate() {
@@ -554,10 +554,10 @@ describe('ReactCompositeComponent', () => {
       }
     }
 
-    const instance = ReactTestUtils.renderIntoDocument(<Component />);
+    const instance = ReactTestUtils.renderIntoDocument(<ClassComponent />);
 
     expect(() => instance.setState({bogus: true})).toErrorDev(
-      'Warning: Component.shouldComponentUpdate(): Returned undefined instead of a ' +
+      'Warning: ClassComponent.shouldComponentUpdate(): Returned undefined instead of a ' +
         'boolean value. Make sure to return true or false.',
     );
   });

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

@@ -291,5 +291,23 @@ describe('ReactDOMServerIntegration', () => {
       },
       'MyComponent.getChildContext(): key "value2" is not defined in childContextTypes.',
     );
+
+    it('warns when childContextTypes is not defined', () => {
+      class MyComponent extends React.Component {
+        render() {
+          return <div />;
+        }
+        getChildContext() {
+          return {value1: 'foo', value2: 'bar'};
+        }
+      }
+
+      expect(() => {
+        ReactDOMServer.renderToString(<MyComponent />);
+      }).toErrorDev(
+        'Warning: MyComponent.getChildContext(): childContextTypes must be defined in order to use getChildContext().\n' +
+          '    in MyComponent (at **)',
+      );
+    });
   });
 });

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

@@ -285,19 +285,21 @@ describe('ReactDOMServerLifecycles', () => {
   });
 
   it('should warn about deprecated lifecycle hooks', () => {
-    class Component extends React.Component {
+    class MyComponent extends React.Component {
       componentWillMount() {}
       render() {
         return null;
       }
     }
 
-    expect(() => ReactDOMServer.renderToString(<Component />)).toWarnDev(
-      'componentWillMount has been renamed',
+    expect(() => ReactDOMServer.renderToString(<MyComponent />)).toWarnDev(
+      'componentWillMount has been renamed, and is not recommended for use. See https://fb.me/react-unsafe-component-lifecycles for details.\n\n' +
+        '* Move code from componentWillMount to componentDidMount (preferred in most cases) or the constructor.\n\n' +
+        'Please update the following components: MyComponent',
     );
 
     // De-duped
-    ReactDOMServer.renderToString(<Component />);
+    ReactDOMServer.renderToString(<MyComponent />);
   });
 
   describe('react-lifecycles-compat', () => {

packages/react-dom/src/__tests__/ReactLegacyContextDisabled-test.internal.js

@@ -11,6 +11,7 @@
 
 let React;
 let ReactDOM;
+let ReactDOMServer;
 let ReactFeatureFlags;
 
 describe('ReactLegacyContextDisabled', () => {
@@ -19,6 +20,7 @@ describe('ReactLegacyContextDisabled', () => {
 
     React = require('react');
     ReactDOM = require('react-dom');
+    ReactDOMServer = require('react-dom/server');
     ReactFeatureFlags = require('shared/ReactFeatureFlags');
     ReactFeatureFlags.disableLegacyContext = true;
   });
@@ -115,6 +117,32 @@ describe('ReactLegacyContextDisabled', () => {
     expect(container.textContent).toBe('{}undefinedundefined');
     expect(lifecycleContextLog).toEqual([{}, {}, {}]);
     ReactDOM.unmountComponentAtNode(container);
+
+    // test server path.
+    let text;
+    expect(() => {
+      text = ReactDOMServer.renderToString(
+        <LegacyProvider>
+          <span>
+            <LegacyClsConsumer />
+            <LegacyFnConsumer />
+            <RegularFn />
+          </span>
+        </LegacyProvider>,
+        container,
+      );
+    }).toErrorDev([
+      'LegacyProvider uses the legacy childContextTypes API which is no longer supported. ' +
+        'Use React.createContext() instead.',
+      'LegacyClsConsumer uses the legacy contextTypes API which is no longer supported. ' +
+        'Use React.createContext() with static contextType instead.',
+      'LegacyFnConsumer uses the legacy contextTypes API which is no longer supported. ' +
+        'Use React.createContext() with React.useContext() instead.',
+    ]);
+    expect(text).toBe(
+      '<span data-reactroot="">{}<!-- -->undefined<!-- -->undefined</span>',
+    );
+    expect(lifecycleContextLog).toEqual([{}, {}, {}]);
   });
 
   it('renders a tree with modern context', () => {

packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.internal.js

@@ -339,6 +339,42 @@ describe('ReactHooksWithNoopRenderer', () => {
       );
     });
 
+    it('dedupes the warning by component name', () => {
+      let _updateCountA;
+      function CounterA(props, ref) {
+        const [, updateCount] = useState(0);
+        _updateCountA = updateCount;
+        return null;
+      }
+      let _updateCountB;
+      function CounterB(props, ref) {
+        const [, updateCount] = useState(0);
+        _updateCountB = updateCount;
+        return null;
+      }
+
+      ReactNoop.render([<CounterA key="A" />, <CounterB key="B" />]);
+      expect(Scheduler).toFlushWithoutYielding();
+      ReactNoop.render(null);
+      expect(Scheduler).toFlushWithoutYielding();
+      expect(() => act(() => _updateCountA(1))).toErrorDev(
+        "Warning: Can't perform a React state update on an unmounted " +
+          'component. This is a no-op, but it indicates a memory leak in your ' +
+          'application. To fix, cancel all subscriptions and asynchronous ' +
+          'tasks in a useEffect cleanup function.\n' +
+          '    in CounterA (at **)',
+      );
+      // already cached so this logs no error
+      act(() => _updateCountA(2));
+      expect(() => act(() => _updateCountB(1))).toErrorDev(
+        "Warning: Can't perform a React state update on an unmounted " +
+          'component. This is a no-op, but it indicates a memory leak in your ' +
+          'application. To fix, cancel all subscriptions and asynchronous ' +
+          'tasks in a useEffect cleanup function.\n' +
+          '    in CounterB (at **)',
+      );
+    });
+
     it('works with memo', () => {
       let _updateCount;
       function Counter(props) {

packages/react/src/ReactElement.js

@@ -114,7 +114,7 @@ function warnIfStringRefCannotBeAutoConverted(config) {
             'We ask you to manually fix this case by using useRef() or createRef() instead. ' +
             'Learn more about using refs safely here: ' +
             'https://fb.me/react-strict-mode-string-ref',
-          getComponentName(ReactCurrentOwner.current.type),
+          componentName,
           config.ref,
         );
         didWarnAboutStringRefs[componentName] = true;