Moved lifecycle deprecation warnings behind (disabled) feature flag

Updated tests accordingly, by temporarily splitting tests that were specific to this feature-flag into their own, internal tests. This was the only way I knew of to interact with the feature flag without breaking our build/dist tests.

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

@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+let React;
+let ReactDOM;
+let ReactFeatureFlags;
+
+/**
+ * TODO: We should make any setState calls fail in
+ * `getInitialState` and `componentWillMount`. They will usually fail
+ * anyways because `this._renderedComponent` is empty, however, if a component
+ * is *reused*, then that won't be the case and things will appear to work in
+ * some cases. Better to just block all updates in initialization.
+ */
+describe('ReactComponentLifeCycle', () => {
+  beforeEach(() => {
+    jest.resetModules();
+
+    ReactFeatureFlags = require('shared/ReactFeatureFlags');
+    ReactFeatureFlags.warnAboutDeprecatedLifecycles = true;
+
+    React = require('react');
+    ReactDOM = require('react-dom');
+  });
+
+  // TODO (RFC #6) Merge this back into ReactComponentLifeCycles-test once
+  // the 'warnAboutDeprecatedLifecycles' feature flag has been removed.
+  it('warns about deprecated unsafe lifecycles', function() {
+    class MyComponent extends React.Component {
+      componentWillMount() {}
+      componentWillReceiveProps() {}
+      componentWillUpdate() {}
+      render() {
+        return null;
+      }
+    }
+
+    const container = document.createElement('div');
+    expect(() => ReactDOM.render(<MyComponent x={1} />, container)).toWarnDev([
+      'Warning: MyComponent: componentWillMount() is deprecated and will be ' +
+        'removed in the next major version. ' +
+        'Please use UNSAFE_componentWillMount() instead.',
+    ]);
+
+    expect(() => ReactDOM.render(<MyComponent x={2} />, container)).toWarnDev([
+      'Warning: MyComponent: componentWillReceiveProps() is deprecated and ' +
+        'will be removed in the next major version. ' +
+        'Please use UNSAFE_componentWillReceiveProps() instead.',
+      'Warning: MyComponent: componentWillUpdate() is deprecated and will be ' +
+        'removed in the next major version. ' +
+        'Please use UNSAFE_componentWillUpdate() instead.',
+    ]);
+
+    // Dedupe check (instantiate and update)
+    ReactDOM.render(<MyComponent key="new" x={1} />, container);
+    ReactDOM.render(<MyComponent key="new" x={2} />, container);
+  });
+});

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

@@ -593,37 +593,6 @@ describe('ReactComponentLifeCycle', () => {
     ]);
   });
 
-  it('warns about deprecated unsafe lifecycles', function() {
-    class MyComponent extends React.Component {
-      componentWillMount() {}
-      componentWillReceiveProps() {}
-      componentWillUpdate() {}
-      render() {
-        return null;
-      }
-    }
-
-    const container = document.createElement('div');
-    expect(() => ReactDOM.render(<MyComponent x={1} />, container)).toWarnDev([
-      'Warning: MyComponent: componentWillMount() is deprecated and will be ' +
-        'removed in the next major version. ' +
-        'Please use UNSAFE_componentWillMount() instead.',
-    ]);
-
-    expect(() => ReactDOM.render(<MyComponent x={2} />, container)).toWarnDev([
-      'Warning: MyComponent: componentWillReceiveProps() is deprecated and ' +
-        'will be removed in the next major version. ' +
-        'Please use UNSAFE_componentWillReceiveProps() instead.',
-      'Warning: MyComponent: componentWillUpdate() is deprecated and will be ' +
-        'removed in the next major version. ' +
-        'Please use UNSAFE_componentWillUpdate() instead.',
-    ]);
-
-    // Dedupe check (instantiate and update)
-    ReactDOM.render(<MyComponent key="new" x={1} />, container);
-    ReactDOM.render(<MyComponent key="new" x={2} />, container);
-  });
-
   it('calls effects on module-pattern component', function() {
     const log = [];
 

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

@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+let React;
+let ReactFeatureFlags;
+let ReactDOMServer;
+
+describe('ReactDOMServerLifecycles', () => {
+  beforeEach(() => {
+    ReactFeatureFlags = require('shared/ReactFeatureFlags');
+    ReactFeatureFlags.warnAboutDeprecatedLifecycles = true;
+
+    React = require('react');
+    ReactDOMServer = require('react-dom/server');
+  });
+
+  // TODO (RFC #6) Merge this back into ReactDOMServerLifecycles-test once
+  // the 'warnAboutDeprecatedLifecycles' feature flag has been removed.
+  it('should warn about deprecated lifecycle hooks', () => {
+    class Component extends React.Component {
+      componentWillMount() {}
+      render() {
+        return null;
+      }
+    }
+
+    expect(() => ReactDOMServer.renderToString(<Component />)).toWarnDev(
+      'Warning: Component: componentWillMount() is deprecated and will be removed ' +
+        'in the next major version. Please use UNSAFE_componentWillMount() instead.',
+    );
+
+    // De-duped
+    ReactDOMServer.renderToString(<Component />);
+  });
+});

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

@@ -65,23 +65,6 @@ describe('ReactDOMServerLifecycles', () => {
     ]);
   });
 
-  it('should warn about deprecated lifecycle hooks', () => {
-    class Component extends React.Component {
-      componentWillMount() {}
-      render() {
-        return null;
-      }
-    }
-
-    expect(() => ReactDOMServer.renderToString(<Component />)).toWarnDev(
-      'Warning: Component: componentWillMount() is deprecated and will be removed ' +
-        'in the next major version. Please use UNSAFE_componentWillMount() instead.',
-    );
-
-    // De-duped
-    ReactDOMServer.renderToString(<Component />);
-  });
-
   it('should update instance.state with value returned from getDerivedStateFromProps', () => {
     class Grandparent extends React.Component {
       state = {

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

@@ -19,6 +19,7 @@ import warning from 'fbjs/lib/warning';
 import checkPropTypes from 'prop-types/checkPropTypes';
 import describeComponentFrame from 'shared/describeComponentFrame';
 import {ReactDebugCurrentFrame} from 'shared/ReactGlobalSharedState';
+import {warnAboutDeprecatedLifecycles} from 'shared/ReactFeatureFlags';
 import {
   REACT_FRAGMENT_TYPE,
   REACT_CALL_TYPE,
@@ -489,16 +490,18 @@ function resolve(
     if (inst.UNSAFE_componentWillMount || inst.componentWillMount) {
       if (inst.componentWillMount) {
         if (__DEV__) {
-          const componentName = getComponentName(Component) || 'Unknown';
+          if (warnAboutDeprecatedLifecycles) {
+            const componentName = getComponentName(Component) || 'Unknown';
 
-          if (!didWarnAboutDeprecatedWillMount[componentName]) {
-            warning(
-              false,
-              '%s: componentWillMount() is deprecated and will be removed in the ' +
-                'next major version. Please use UNSAFE_componentWillMount() instead.',
-              componentName,
-            );
-            didWarnAboutDeprecatedWillMount[componentName] = true;
+            if (!didWarnAboutDeprecatedWillMount[componentName]) {
+              warning(
+                false,
+                '%s: componentWillMount() is deprecated and will be removed in the ' +
+                  'next major version. Please use UNSAFE_componentWillMount() instead.',
+                componentName,
+              );
+              didWarnAboutDeprecatedWillMount[componentName] = true;
+            }
           }
         }
 

packages/react-reconciler/src/ReactFiberClassComponent.js

@@ -14,6 +14,7 @@ import {Update} from 'shared/ReactTypeOfSideEffect';
 import {
   debugRenderPhaseSideEffects,
   enableAsyncSubtreeAPI,
+  warnAboutDeprecatedLifecycles,
 } from 'shared/ReactFeatureFlags';
 import {isMounted} from 'react-reconciler/reflection';
 import * as ReactInstanceMap from 'shared/ReactInstanceMap';
@@ -49,9 +50,11 @@ let didWarnAboutWillReceivePropsAndDerivedState;
 let warnOnInvalidCallback;
 
 if (__DEV__) {
-  didWarnAboutLegacyWillMount = {};
-  didWarnAboutLegacyWillReceiveProps = {};
-  didWarnAboutLegacyWillUpdate = {};
+  if (warnAboutDeprecatedLifecycles) {
+    didWarnAboutLegacyWillMount = {};
+    didWarnAboutLegacyWillReceiveProps = {};
+    didWarnAboutLegacyWillUpdate = {};
+  }
   didWarnAboutStateAssignmentForComponent = {};
   didWarnAboutUndefinedDerivedState = {};
   didWarnAboutWillReceivePropsAndDerivedState = {};
@@ -426,15 +429,17 @@ export default function(
 
     if (typeof instance.componentWillMount === 'function') {
       if (__DEV__) {
-        const componentName = getComponentName(workInProgress) || 'Unknown';
-        if (!didWarnAboutLegacyWillMount[componentName]) {
-          warning(
-            false,
-            '%s: componentWillMount() is deprecated and will be removed in the ' +
-              'next major version. Please use UNSAFE_componentWillMount() instead.',
-            componentName,
-          );
-          didWarnAboutLegacyWillMount[componentName] = true;
+        if (warnAboutDeprecatedLifecycles) {
+          const componentName = getComponentName(workInProgress) || 'Unknown';
+          if (!didWarnAboutLegacyWillMount[componentName]) {
+            warning(
+              false,
+              '%s: componentWillMount() is deprecated and will be removed in the ' +
+                'next major version. Please use UNSAFE_componentWillMount() instead.',
+              componentName,
+            );
+            didWarnAboutLegacyWillMount[componentName] = true;
+          }
         }
       }
       instance.componentWillMount();
@@ -467,15 +472,17 @@ export default function(
     const oldState = instance.state;
     if (typeof instance.componentWillReceiveProps === 'function') {
       if (__DEV__) {
-        const componentName = getComponentName(workInProgress) || 'Unknown';
-        if (!didWarnAboutLegacyWillReceiveProps[componentName]) {
-          warning(
-            false,
-            '%s: componentWillReceiveProps() is deprecated and will be removed in the ' +
-              'next major version. Please use UNSAFE_componentWillReceiveProps() instead.',
-            componentName,
-          );
-          didWarnAboutLegacyWillReceiveProps[componentName] = true;
+        if (warnAboutDeprecatedLifecycles) {
+          const componentName = getComponentName(workInProgress) || 'Unknown';
+          if (!didWarnAboutLegacyWillReceiveProps[componentName]) {
+            warning(
+              false,
+              '%s: componentWillReceiveProps() is deprecated and will be removed in the ' +
+                'next major version. Please use UNSAFE_componentWillReceiveProps() instead.',
+              componentName,
+            );
+            didWarnAboutLegacyWillReceiveProps[componentName] = true;
+          }
         }
       }
 
@@ -814,16 +821,18 @@ export default function(
       ) {
         if (typeof instance.componentWillUpdate === 'function') {
           if (__DEV__) {
-            const componentName =
-              getComponentName(workInProgress) || 'Component';
-            if (!didWarnAboutLegacyWillUpdate[componentName]) {
-              warning(
-                false,
-                '%s: componentWillUpdate() is deprecated and will be removed in the ' +
-                  'next major version. Please use UNSAFE_componentWillUpdate() instead.',
-                componentName,
-              );
-              didWarnAboutLegacyWillUpdate[componentName] = true;
+            if (warnAboutDeprecatedLifecycles) {
+              const componentName =
+                getComponentName(workInProgress) || 'Component';
+              if (!didWarnAboutLegacyWillUpdate[componentName]) {
+                warning(
+                  false,
+                  '%s: componentWillUpdate() is deprecated and will be removed in the ' +
+                    'next major version. Please use UNSAFE_componentWillUpdate() instead.',
+                  componentName,
+                );
+                didWarnAboutLegacyWillUpdate[componentName] = true;
+              }
             }
           }