[#9627] Fix create-react-class isMounted ordering issue (#9638)

* [#9627] Fix create-react-class isMounted ordering issue

Split the IsMountedMixin in two so that the __isMounted flag is set to false after componentWillUnmount is executed in mixins and the component.

* Revert changes to integration test

addons/create-react-class/factory.js

@@ -584,10 +584,13 @@ function factory(ReactComponent, isValidElement, ReactNoopUpdateQueue) {
     }
   }
 
-  var IsMountedMixin = {
+  var IsMountedPreMixin = {
     componentDidMount: function () {
       this.__isMounted = true;
-    },
+    }
+  };
+
+  var IsMountedPostMixin = {
     componentWillUnmount: function () {
       this.__isMounted = false;
     }
@@ -679,8 +682,9 @@ function factory(ReactComponent, isValidElement, ReactNoopUpdateQueue) {
 
     injectedMixins.forEach(mixSpecIntoComponent.bind(null, Constructor));
 
-    mixSpecIntoComponent(Constructor, IsMountedMixin);
+    mixSpecIntoComponent(Constructor, IsMountedPreMixin);
     mixSpecIntoComponent(Constructor, spec);
+    mixSpecIntoComponent(Constructor, IsMountedPostMixin);
 
     // Initialize the defaultProps property after all mixins have been merged.
     if (Constructor.getDefaultProps) {

addons/create-react-class/test.js

@@ -394,6 +394,25 @@ describe('ReactClass-spec', () => {
     var instance;
     var Component = createReactClass({
       displayName: 'MyComponent',
+      mixins: [
+        {
+          componentWillMount() {
+            this.log('mixin.componentWillMount');
+          },
+          componentDidMount() {
+            this.log('mixin.componentDidMount');
+          },
+          componentWillUpdate() {
+            this.log('mixin.componentWillUpdate');
+          },
+          componentDidUpdate() {
+            this.log('mixin.componentDidUpdate');
+          },
+          componentWillUnmount() {
+            this.log('mixin.componentWillUnmount');
+          },
+        },
+      ],
       log(name) {
         ops.push(`${name}: ${this.isMounted()}`);
       },
@@ -430,13 +449,18 @@ describe('ReactClass-spec', () => {
     instance.log('after unmount');
     expect(ops).toEqual([
       'getInitialState: false',
+      'mixin.componentWillMount: false',
       'componentWillMount: false',
       'render: false',
+      'mixin.componentDidMount: true',
       'componentDidMount: true',
+      'mixin.componentWillUpdate: true',
       'componentWillUpdate: true',
       'render: true',
+      'mixin.componentDidUpdate: true',
       'componentDidUpdate: true',
-      'componentWillUnmount: false',
+      'mixin.componentWillUnmount: true',
+      'componentWillUnmount: true',
       'after unmount: false',
     ]);