unify deprecated/unsafe lifecycle warnings, pass tests

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

@@ -709,9 +709,9 @@ describe('ReactComponentLifeCycle', () => {
       );
     }).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated',
-        'componentWillReceiveProps is deprecated',
-        'componentWillUpdate is deprecated',
+        'componentWillMount has been renamed',
+        'componentWillReceiveProps has been renamed',
+        'componentWillUpdate has been renamed',
       ],
       {withoutStack: true},
     );
@@ -748,9 +748,9 @@ describe('ReactComponentLifeCycle', () => {
       );
     }).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated',
-        'componentWillReceiveProps is deprecated',
-        'componentWillUpdate is deprecated',
+        'componentWillMount has been renamed',
+        'componentWillReceiveProps has been renamed',
+        'componentWillUpdate has been renamed',
       ],
       {withoutStack: true},
     );
@@ -815,7 +815,10 @@ describe('ReactComponentLifeCycle', () => {
         {withoutStack: true},
       );
     }).toLowPriorityWarnDev(
-      ['componentWillMount is deprecated', 'componentWillUpdate is deprecated'],
+      [
+        'componentWillMount has been renamed',
+        'componentWillUpdate has been renamed',
+      ],
       {withoutStack: true},
     );
 
@@ -863,7 +866,7 @@ describe('ReactComponentLifeCycle', () => {
           'https://fb.me/react-async-component-lifecycle-hooks',
         {withoutStack: true},
       );
-    }).toLowPriorityWarnDev(['componentWillMount is deprecated'], {
+    }).toLowPriorityWarnDev(['componentWillMount has been renamed'], {
       withoutStack: true,
     });
 
@@ -887,7 +890,7 @@ describe('ReactComponentLifeCycle', () => {
           'https://fb.me/react-async-component-lifecycle-hooks',
         {withoutStack: true},
       );
-    }).toLowPriorityWarnDev(['componentWillReceiveProps is deprecated'], {
+    }).toLowPriorityWarnDev(['componentWillReceiveProps has been renamed'], {
       withoutStack: true,
     });
   });
@@ -921,7 +924,10 @@ describe('ReactComponentLifeCycle', () => {
         {withoutStack: true},
       );
     }).toLowPriorityWarnDev(
-      ['componentWillMount is deprecated', 'componentWillUpdate is deprecated'],
+      [
+        'componentWillMount has been renamed',
+        'componentWillUpdate has been renamed',
+      ],
       {withoutStack: true},
     );
 
@@ -967,7 +973,7 @@ describe('ReactComponentLifeCycle', () => {
           'https://fb.me/react-async-component-lifecycle-hooks',
         {withoutStack: true},
       );
-    }).toLowPriorityWarnDev(['componentWillMount is deprecated'], {
+    }).toLowPriorityWarnDev(['componentWillMount has been renamed'], {
       withoutStack: true,
     });
 
@@ -990,7 +996,7 @@ describe('ReactComponentLifeCycle', () => {
           'https://fb.me/react-async-component-lifecycle-hooks',
         {withoutStack: true},
       );
-    }).toLowPriorityWarnDev(['componentWillReceiveProps is deprecated'], {
+    }).toLowPriorityWarnDev(['componentWillReceiveProps has been renamed'], {
       withoutStack: true,
     });
   });
@@ -1130,9 +1136,9 @@ describe('ReactComponentLifeCycle', () => {
       ReactDOM.render(<MyComponent foo="bar" />, div),
     ).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated',
-        'componentWillReceiveProps is deprecated',
-        'componentWillUpdate is deprecated',
+        'componentWillMount has been renamed',
+        'componentWillReceiveProps has been renamed',
+        'componentWillUpdate has been renamed',
       ],
       {withoutStack: true},
     );
@@ -1403,22 +1409,32 @@ describe('ReactComponentLifeCycle', () => {
       ReactDOM.render(<MyComponent x={1} />, container),
     ).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated and will be removed in the next major version. ' +
-          'Use componentDidMount instead. As a temporary workaround, ' +
-          'you can rename to UNSAFE_componentWillMount.' +
-          '\n\nPlease update the following components: MyComponent',
-        'componentWillReceiveProps is deprecated and will be removed in the next major version. ' +
-          'Use static getDerivedStateFromProps instead.' +
-          '\n\nPlease update the following components: MyComponent',
-        'componentWillUpdate is deprecated and will be removed in the next major version. ' +
-          'Use componentDidUpdate instead. As a temporary workaround, ' +
-          'you can rename to UNSAFE_componentWillUpdate.' +
-          '\n\nPlease update the following components: MyComponent',
+        /* eslint-disable max-len */
+        `Warning: componentWillMount has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move code with side effects to componentDidMount, and set initial state in the constructor.
+* Rename componentWillMount to UNSAFE_componentWillMount to suppress this warning in non-strict mode. In React 17.x, only the UNSAFE_ name will work. To rename all deprecated lifecycles to their new names, you can run \`npx react-codemod rename-unsafe-lifecycles\` in your project source folder.
+
+Please update the following components: MyComponent`,
+        `Warning: componentWillReceiveProps has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+* If you're updating state whenever props change, refactor your code to use memoization techniques or move it to static getDerivedStateFromProps. Learn more at: https://fb.me/react-derived-state
+* Rename componentWillReceiveProps to UNSAFE_componentWillReceiveProps to suppress this warning in non-strict mode. In React 17.x, only the UNSAFE_ name will work. To rename all deprecated lifecycles to their new names, you can run \`npx react-codemod rename-unsafe-lifecycles\` in your project source folder.
+
+Please update the following components: MyComponent`,
+        `Warning: componentWillUpdate has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+* Rename componentWillUpdate to UNSAFE_componentWillUpdate to suppress this warning in non-strict mode. In React 17.x, only the UNSAFE_ name will work. To rename all deprecated lifecycles to their new names, you can run \`npx react-codemod rename-unsafe-lifecycles\` in your project source folder.
+
+Please update the following components: MyComponent`,
+        /* eslint-enable max-len */
       ],
       {withoutStack: true},
     );
 
-    // Dedupe check (update and instantiate new
+    // Dedupe check (update and instantiate new)
     ReactDOM.render(<MyComponent x={2} />, container);
     ReactDOM.render(<MyComponent key="new" x={1} />, container);
   });

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

@@ -229,7 +229,7 @@ describe('ReactDOMServerLifecycles', () => {
 
     expect(() =>
       ReactDOMServer.renderToString(<Component />),
-    ).toLowPriorityWarnDev('componentWillMount() is deprecated', {
+    ).toLowPriorityWarnDev('componentWillMount has been renamed', {
       withoutStack: true,
     });
     expect(log).toEqual(['componentWillMount', 'UNSAFE_componentWillMount']);
@@ -286,10 +286,9 @@ describe('ReactDOMServerLifecycles', () => {
 
     expect(() =>
       ReactDOMServer.renderToString(<Component />),
-    ).toLowPriorityWarnDev(
-      'Component: componentWillMount() is deprecated and will be removed in the next major version.',
-      {withoutStack: true},
-    );
+    ).toLowPriorityWarnDev('componentWillMount has been renamed', {
+      withoutStack: true,
+    });
   });
 
   it('should warn about deprecated lifecycle hooks', () => {
@@ -302,11 +301,9 @@ describe('ReactDOMServerLifecycles', () => {
 
     expect(() =>
       ReactDOMServer.renderToString(<Component />),
-    ).toLowPriorityWarnDev(
-      'Warning: Component: componentWillMount() is deprecated and will be removed ' +
-        'in the next major version.',
-      {withoutStack: true},
-    );
+    ).toLowPriorityWarnDev('componentWillMount has been renamed', {
+      withoutStack: true,
+    });
 
     // De-duped
     ReactDOMServer.renderToString(<Component />);

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

@@ -362,20 +362,16 @@ describe('ReactDOMServerHydration', () => {
     const element = document.createElement('div');
     expect(() => {
       element.innerHTML = ReactDOMServer.renderToString(markup);
-    }).toLowPriorityWarnDev(
-      ['componentWillMount() is deprecated and will be removed'],
-      {withoutStack: true},
-    );
+    }).toLowPriorityWarnDev(['componentWillMount has been renamed'], {
+      withoutStack: true,
+    });
     expect(element.textContent).toBe('Hi');
 
     expect(() => {
-      expect(() => ReactDOM.hydrate(markup, element)).toWarnDev(
-        'Please update the following components to use componentDidMount instead: ComponentWithWarning',
-      );
-    }).toLowPriorityWarnDev(
-      ['componentWillMount is deprecated and will be removed'],
-      {withoutStack: true},
-    );
+      ReactDOM.hydrate(markup, element);
+    }).toLowPriorityWarnDev(['componentWillMount has been renamed'], {
+      withoutStack: true,
+    });
     expect(element.textContent).toBe('Hi');
   });
 

packages/react-dom/src/server/ReactPartialRenderer.js

@@ -572,13 +572,12 @@ function resolve(
             if (!didWarnAboutDeprecatedWillMount[componentName]) {
               lowPriorityWarning(
                 false,
-                '%s: componentWillMount() is deprecated and will be ' +
-                  'removed in the next major version. Read about the motivations ' +
-                  'behind this change: ' +
-                  'https://fb.me/react-async-component-lifecycle-hooks' +
-                  '\n\n' +
-                  'As a temporary workaround, you can rename to ' +
-                  'UNSAFE_componentWillMount instead.',
+                // keep this warning in sync with ReactStrictModeWarning.js
+                'componentWillMount has been renamed, and is not recommended for use. ' +
+                  'See https://fb.me/react-async-component-lifecycle-hooks for details.\n\n' +
+                  '* Move code from componentWillMount to componentDidMount (preferred in most cases) ' +
+                  'or the constructor.\n' +
+                  '\nPlease update the following components: %s',
                 componentName,
               );
               didWarnAboutDeprecatedWillMount[componentName] = true;

packages/react-reconciler/src/ReactFiberClassComponent.js

@@ -806,19 +806,14 @@ function mountClassInstance(
     }
 
     if (workInProgress.mode & StrictMode) {
-      ReactStrictModeWarnings.recordUnsafeLifecycleWarnings(
-        workInProgress,
-        instance,
-      );
-
       ReactStrictModeWarnings.recordLegacyContextWarning(
         workInProgress,
         instance,
       );
     }
 
     if (warnAboutDeprecatedLifecycles) {
-      ReactStrictModeWarnings.recordDeprecationWarnings(
+      ReactStrictModeWarnings.recordUnsafeLifecycleWarnings(
         workInProgress,
         instance,
       );

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -2247,11 +2247,10 @@ function checkForNestedUpdates() {
 
 function flushRenderPhaseStrictModeWarningsInDEV() {
   if (__DEV__) {
-    ReactStrictModeWarnings.flushPendingUnsafeLifecycleWarnings();
     ReactStrictModeWarnings.flushLegacyContextWarning();
 
     if (warnAboutDeprecatedLifecycles) {
-      ReactStrictModeWarnings.flushPendingDeprecationWarnings();
+      ReactStrictModeWarnings.flushPendingUnsafeLifecycleWarnings();
     }
   }
 }

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

@@ -2446,8 +2446,7 @@ describe('ReactIncremental', () => {
     ReactNoop.render(<MyComponent />);
     expect(() => expect(Scheduler).toFlushWithoutYielding()).toWarnDev(
       [
-        'componentWillReceiveProps: Please update the following components ' +
-          'to use static getDerivedStateFromProps instead: MyComponent',
+        'Using UNSAFE_componentWillReceiveProps in strict mode is not recommended',
         'Legacy context API has been detected within a strict-mode tree: \n\n' +
           'Please update the following components: MyComponent',
       ],
@@ -2887,26 +2886,35 @@ describe('ReactIncremental', () => {
     expect(Scheduler).toFlushAndYield([]);
   });
 
-  // We don't currently use fibers as keys. Re-enable this test if we
-  // ever do again.
+  // We sometimes use Maps with Fibers as keys.
   it('does not break with a bad Map polyfill', () => {
     const realMapSet = Map.prototype.set;
 
     function triggerCodePathThatUsesFibersAsMapKeys() {
       function Thing() {
         throw new Error('No.');
       }
+      // This class uses legacy context, which triggers warnings,
+      // the procedures for which use a Map to store fibers.
       class Boundary extends React.Component {
         state = {didError: false};
         componentDidCatch() {
           this.setState({didError: true});
         }
+        static contextTypes = {
+          color: () => null,
+        };
         render() {
           return this.state.didError ? null : <Thing />;
         }
       }
       ReactNoop.render(<Boundary />);
-      expect(Scheduler).toFlushWithoutYielding();
+      expect(() => {
+        expect(Scheduler).toFlushWithoutYielding();
+      }).toWarnDev(
+        ['Legacy context API has been detected within a strict-mode tree'],
+        {withoutStack: true},
+      );
     }
 
     // First, verify that this code path normally receives Fibers as keys,
@@ -2952,6 +2960,7 @@ describe('ReactIncremental', () => {
     };
     React = require('react');
     ReactNoop = require('react-noop-renderer');
+    Scheduler = require('scheduler');
     try {
       triggerCodePathThatUsesFibersAsMapKeys();
     } finally {

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

@@ -316,10 +316,8 @@ describe('ReactDebugFiberPerf', () => {
     addComment('Should not print a warning');
     expect(() => expect(Scheduler).toFlushWithoutYielding()).toWarnDev(
       [
-        'componentWillMount: Please update the following components ' +
-          'to use componentDidMount instead: NotCascading' +
-          '\n\ncomponentWillReceiveProps: Please update the following components ' +
-          'to use static getDerivedStateFromProps instead: NotCascading',
+        'Using UNSAFE_componentWillMount in strict mode is not recommended',
+        'Using UNSAFE_componentWillReceiveProps in strict mode is not recommended',
       ],
       {withoutStack: true},
     );
@@ -358,14 +356,10 @@ describe('ReactDebugFiberPerf', () => {
     addComment('Mount');
     expect(() => expect(Scheduler).toFlushWithoutYielding()).toWarnDev(
       [
-        'componentWillMount: Please update the following components ' +
-          'to use componentDidMount instead: AllLifecycles' +
-          '\n\ncomponentWillReceiveProps: Please update the following components ' +
-          'to use static getDerivedStateFromProps instead: AllLifecycles' +
-          '\n\ncomponentWillUpdate: Please update the following components ' +
-          'to use componentDidUpdate instead: AllLifecycles',
-        'Legacy context API has been detected within a strict-mode tree: \n\n' +
-          'Please update the following components: AllLifecycles',
+        'Using UNSAFE_componentWillMount in strict mode is not recommended',
+        'Using UNSAFE_componentWillReceiveProps in strict mode is not recommended',
+        'Using UNSAFE_componentWillUpdate in strict mode is not recommended',
+        'Legacy context API has been detected within a strict-mode tree',
       ],
       {withoutStack: true},
     );

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

@@ -76,8 +76,7 @@ describe('ReactIncrementalReflection', () => {
     expect(() =>
       expect(Scheduler).toFlushAndYield(['componentDidMount: true']),
     ).toWarnDev(
-      'componentWillMount: Please update the following components ' +
-        'to use componentDidMount instead: Component',
+      'Using UNSAFE_componentWillMount in strict mode is not recommended',
       {withoutStack: true},
     );
 
@@ -116,8 +115,7 @@ describe('ReactIncrementalReflection', () => {
 
     ReactNoop.render(<Foo mount={true} />);
     expect(() => expect(Scheduler).toFlushAndYield(['Component'])).toWarnDev(
-      'componentWillMount: Please update the following components ' +
-        'to use componentDidMount instead: Component',
+      'Using UNSAFE_componentWillMount in strict mode is not recommended',
       {withoutStack: true},
     );
 
@@ -222,10 +220,10 @@ describe('ReactIncrementalReflection', () => {
     expect(() =>
       expect(Scheduler).toFlushAndYield([['componentDidMount', span()]]),
     ).toWarnDev(
-      'componentWillMount: Please update the following components ' +
-        'to use componentDidMount instead: Component' +
-        '\n\ncomponentWillUpdate: Please update the following components ' +
-        'to use componentDidUpdate instead: Component',
+      [
+        'Using UNSAFE_componentWillMount in strict mode is not recommended',
+        'Using UNSAFE_componentWillUpdate in strict mode is not recommended',
+      ],
       {withoutStack: true},
     );
 

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

@@ -346,8 +346,7 @@ describe('ReactIncrementalUpdates', () => {
     }
     ReactNoop.render(<Foo />);
     expect(() => expect(Scheduler).toFlushWithoutYielding()).toWarnDev(
-      'componentWillReceiveProps: Please update the following components ' +
-        'to use static getDerivedStateFromProps instead: Foo',
+      'Using UNSAFE_componentWillReceiveProps in strict mode is not recommended',
       {withoutStack: true},
     );
 

packages/react/src/__tests__/ReactStrictMode-test.internal.js

@@ -349,15 +349,26 @@ describe('ReactStrictMode', () => {
       });
       root.update(<AsyncRoot />);
       expect(() => Scheduler.unstable_flushAll()).toWarnDev(
-        'Unsafe lifecycle methods were found within a strict-mode tree:' +
-          '\n\ncomponentWillMount: Please update the following components ' +
-          'to use componentDidMount instead: AsyncRoot' +
-          '\n\ncomponentWillReceiveProps: Please update the following components ' +
-          'to use static getDerivedStateFromProps instead: Bar, Foo' +
-          '\n\ncomponentWillUpdate: Please update the following components ' +
-          'to use componentDidUpdate instead: AsyncRoot' +
-          '\n\nLearn more about this warning here:' +
-          '\nhttps://fb.me/react-strict-mode-warnings',
+        [
+          /* eslint-disable max-len */
+          `Warning: Using UNSAFE_componentWillMount in strict mode is not recommended and may indicate bugs in your code. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move code with side effects to componentDidMount, and set initial state in the constructor.
+
+Please update the following components: AsyncRoot`,
+          `Warning: Using UNSAFE_componentWillReceiveProps in strict mode is not recommended and may indicate bugs in your code. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+* If you're updating state whenever props change, refactor your code to use memoization techniques or move it to static getDerivedStateFromProps. Learn more at: https://fb.me/react-derived-state
+
+Please update the following components: Bar, Foo`,
+          `Warning: Using UNSAFE_componentWillUpdate in strict mode is not recommended and may indicate bugs in your code. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+
+Please update the following components: AsyncRoot`,
+          /* eslint-enable max-len */
+        ],
         {withoutStack: true},
       );
 
@@ -396,26 +407,54 @@ describe('ReactStrictMode', () => {
 
       expect(() => {
         expect(() => Scheduler.unstable_flushAll()).toWarnDev(
-          'Unsafe lifecycle methods were found within a strict-mode tree:' +
-            '\n\ncomponentWillMount: Please update the following components ' +
-            'to use componentDidMount instead: AsyncRoot, Parent' +
-            '\n\ncomponentWillReceiveProps: Please update the following components ' +
-            'to use static getDerivedStateFromProps instead: Child, Parent' +
-            '\n\ncomponentWillUpdate: Please update the following components ' +
-            'to use componentDidUpdate instead: AsyncRoot, Parent' +
-            '\n\nLearn more about this warning here:' +
-            '\nhttps://fb.me/react-strict-mode-warnings',
+          [
+            /* eslint-disable max-len */
+            `Warning: Using UNSAFE_componentWillMount in strict mode is not recommended and may indicate bugs in your code. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move code with side effects to componentDidMount, and set initial state in the constructor.
+
+Please update the following components: AsyncRoot`,
+            `Warning: Using UNSAFE_componentWillReceiveProps in strict mode is not recommended and may indicate bugs in your code. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+* If you're updating state whenever props change, refactor your code to use memoization techniques or move it to static getDerivedStateFromProps. Learn more at: https://fb.me/react-derived-state
+
+Please update the following components: Child`,
+            `Warning: Using UNSAFE_componentWillUpdate in strict mode is not recommended and may indicate bugs in your code. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+
+Please update the following components: AsyncRoot`,
+            /* eslint-enable max-len */
+          ],
           {withoutStack: true},
         );
       }).toLowPriorityWarnDev(
         [
-          'componentWillMount is deprecated',
-          'componentWillReceiveProps is deprecated',
-          'componentWillUpdate is deprecated',
+          /* eslint-disable max-len */
+          `Warning: componentWillMount has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move code with side effects to componentDidMount, and set initial state in the constructor.
+* Rename componentWillMount to UNSAFE_componentWillMount to suppress this warning in non-strict mode. In React 17.x, only the UNSAFE_ name will work. To rename all deprecated lifecycles to their new names, you can run \`npx react-codemod rename-unsafe-lifecycles\` in your project source folder.
+
+Please update the following components: Parent`,
+          `Warning: componentWillReceiveProps has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+* If you're updating state whenever props change, refactor your code to use memoization techniques or move it to static getDerivedStateFromProps. Learn more at: https://fb.me/react-derived-state
+* Rename componentWillReceiveProps to UNSAFE_componentWillReceiveProps to suppress this warning in non-strict mode. In React 17.x, only the UNSAFE_ name will work. To rename all deprecated lifecycles to their new names, you can run \`npx react-codemod rename-unsafe-lifecycles\` in your project source folder.
+
+Please update the following components: Parent`,
+          `Warning: componentWillUpdate has been renamed, and is not recommended for use. See https://fb.me/react-async-component-lifecycle-hooks for details.
+
+* Move data fetching code or side effects to componentDidUpdate.
+* Rename componentWillUpdate to UNSAFE_componentWillUpdate to suppress this warning in non-strict mode. In React 17.x, only the UNSAFE_ name will work. To rename all deprecated lifecycles to their new names, you can run \`npx react-codemod rename-unsafe-lifecycles\` in your project source folder.
+
+Please update the following components: Parent`,
+          /* eslint-enable max-len */
         ],
         {withoutStack: true},
       );
-
       // Dedupe
       root.update(<AsyncRoot />);
       Scheduler.unstable_flushAll();
@@ -445,21 +484,13 @@ describe('ReactStrictMode', () => {
       });
       root.update(<AsyncRoot foo={true} />);
       expect(() => Scheduler.unstable_flushAll()).toWarnDev(
-        'Unsafe lifecycle methods were found within a strict-mode tree:' +
-          '\n\ncomponentWillMount: Please update the following components ' +
-          'to use componentDidMount instead: Foo' +
-          '\n\nLearn more about this warning here:' +
-          '\nhttps://fb.me/react-strict-mode-warnings',
+        'Using UNSAFE_componentWillMount in strict mode is not recommended',
         {withoutStack: true},
       );
 
       root.update(<AsyncRoot foo={false} />);
       expect(() => Scheduler.unstable_flushAll()).toWarnDev(
-        'Unsafe lifecycle methods were found within a strict-mode tree:' +
-          '\n\ncomponentWillMount: Please update the following components ' +
-          'to use componentDidMount instead: Bar' +
-          '\n\nLearn more about this warning here:' +
-          '\nhttps://fb.me/react-strict-mode-warnings',
+        'Using UNSAFE_componentWillMount in strict mode is not recommended',
         {withoutStack: true},
       );
 
@@ -507,13 +538,8 @@ describe('ReactStrictMode', () => {
       }
 
       expect(() => ReactTestRenderer.create(<SyncRoot />)).toWarnDev(
-        'Unsafe lifecycle methods were found within a strict-mode tree:' +
-          '\n    in StrictMode (at **)' +
-          '\n    in SyncRoot (at **)' +
-          '\n\ncomponentWillReceiveProps: Please update the following components ' +
-          'to use static getDerivedStateFromProps instead: Bar, Foo' +
-          '\n\nLearn more about this warning here:' +
-          '\nhttps://fb.me/react-strict-mode-warnings',
+        'Using UNSAFE_componentWillReceiveProps in strict mode is not recommended',
+        {withoutStack: true},
       );
 
       // Dedupe

packages/react/src/__tests__/createReactClassIntegration-test.internal.js

@@ -51,10 +51,7 @@ describe('create-react-class-integration', () => {
       });
 
       expect(() => ReactNative.render(<View />, 1)).toLowPriorityWarnDev(
-        'componentWillMount is deprecated and will be removed in the next major version. ' +
-          'Use componentDidMount instead. As a temporary workaround, ' +
-          'you can rename to UNSAFE_componentWillMount.' +
-          '\n\nPlease update the following components: MyNativeComponent',
+        'componentWillMount has been renamed',
         {withoutStack: true},
       );
     });
@@ -68,9 +65,7 @@ describe('create-react-class-integration', () => {
       });
 
       expect(() => ReactNative.render(<View />, 1)).toLowPriorityWarnDev(
-        'componentWillReceiveProps is deprecated and will be removed in the next major version. ' +
-          'Use static getDerivedStateFromProps instead.' +
-          '\n\nPlease update the following components: MyNativeComponent',
+        'componentWillReceiveProps has been renamed',
         {withoutStack: true},
       );
     });

packages/react/src/__tests__/createReactClassIntegration-test.js

@@ -560,9 +560,9 @@ describe('create-react-class-integration', () => {
       );
     }).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated',
-        'componentWillReceiveProps is deprecated',
-        'componentWillUpdate is deprecated',
+        'componentWillMount has been renamed',
+        'componentWillReceiveProps has been renamed',
+        'componentWillUpdate has been renamed',
       ],
       {withoutStack: true},
     );
@@ -604,9 +604,9 @@ describe('create-react-class-integration', () => {
       );
     }).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated',
-        'componentWillReceiveProps is deprecated',
-        'componentWillUpdate is deprecated',
+        'componentWillMount has been renamed',
+        'componentWillReceiveProps has been renamed',
+        'componentWillUpdate has been renamed',
       ],
       {withoutStack: true},
     );
@@ -649,9 +649,9 @@ describe('create-react-class-integration', () => {
       ReactDOM.render(<Component foo="bar" />, div),
     ).toLowPriorityWarnDev(
       [
-        'componentWillMount is deprecated',
-        'componentWillReceiveProps is deprecated',
-        'componentWillUpdate is deprecated',
+        'componentWillMount has been renamed',
+        'componentWillReceiveProps has been renamed',
+        'componentWillUpdate has been renamed',
       ],
       {withoutStack: true},
     );

packages/shared/forks/ReactFeatureFlags.test-renderer.js

@@ -15,7 +15,7 @@ import typeof * as PersistentFeatureFlagsType from './ReactFeatureFlags.persiste
 export const debugRenderPhaseSideEffects = false;
 export const debugRenderPhaseSideEffectsForStrictMode = false;
 export const enableUserTimingAPI = __DEV__;
-export const warnAboutDeprecatedLifecycles = false;
+export const warnAboutDeprecatedLifecycles = true;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = false;
 export const enableProfilerTimer = false;
 export const enableSchedulerTracing = false;

scripts/print-warnings/print-warnings.js

@@ -52,8 +52,17 @@ function transform(file, enc, cb) {
 
             // warning messages can be concatenated (`+`) at runtime, so here's
             // a trivial partial evaluator that interprets the literal value
-            const warningMsgLiteral = evalToString(node.arguments[1]);
-            warnings.add(JSON.stringify(warningMsgLiteral));
+            try {
+              const warningMsgLiteral = evalToString(node.arguments[1]);
+              warnings.add(JSON.stringify(warningMsgLiteral));
+            } catch (error) {
+              console.error(
+                'Failed to extract warning message from',
+                file.path
+              );
+              console.error(astPath.node.loc);
+              throw error;
+            }
           }
         },
       },