Add nextContext to componentWillReceiveProps

Add `nextContext` as an argument to `componentWillReceiveProps`. We can figure out what to rename the method to later.

src/core/ReactCompositeComponent.js

@@ -202,7 +202,7 @@ var ReactCompositeComponentInterface = {
    * Use this as an opportunity to react to a prop transition by updating the
    * state using `this.setState`. Current props are accessed via `this.props`.
    *
-   *   componentWillReceiveProps: function(nextProps) {
+   *   componentWillReceiveProps: function(nextProps, nextContext) {
    *     this.setState({
    *       likesIncreasing: nextProps.likeCount > this.props.likeCount
    *     });
@@ -823,6 +823,10 @@ var ReactCompositeComponentMixin = {
       return;
     }
 
+    var nextFullContext = this._pendingContext || this._currentContext;
+    var nextContext = this._processContext(nextFullContext);
+    this._pendingContext = null;
+
     var nextProps = this.props;
     if (this._pendingProps != null) {
       nextProps = this._pendingProps;
@@ -831,7 +835,7 @@ var ReactCompositeComponentMixin = {
 
       this._compositeLifeCycleState = CompositeLifeCycle.RECEIVING_PROPS;
       if (this.componentWillReceiveProps) {
-        this.componentWillReceiveProps(nextProps);
+        this.componentWillReceiveProps(nextProps, nextContext);
       }
     }
 
@@ -840,10 +844,6 @@ var ReactCompositeComponentMixin = {
     var nextState = this._pendingState || this.state;
     this._pendingState = null;
 
-    var nextFullContext = this._pendingContext || this._currentContext;
-    var nextContext = this._processContext(nextFullContext);
-    this._pendingContext = null;
-
     if (this._pendingForceUpdate ||
         !this.shouldComponentUpdate ||
         this.shouldComponentUpdate(nextProps, nextState, nextContext)) {

src/core/__tests__/ReactCompositeComponent-test.js

@@ -639,6 +639,7 @@ describe('ReactCompositeComponent', function() {
   });
 
   it('should filter context properly in callbacks', function() {
+    var actualComponentWillReceiveProps;
     var actualShouldComponentUpdate;
     var actualComponentWillUpdate;
     var actualComponentDidUpdate;
@@ -666,6 +667,11 @@ describe('ReactCompositeComponent', function() {
         foo: ReactPropTypes.string
       },
 
+      componentWillReceiveProps: function(nextProps, nextContext) {
+        actualComponentWillReceiveProps = nextContext;
+        return true;
+      },
+
       shouldComponentUpdate: function(nextProps, nextState, nextContext) {
         actualShouldComponentUpdate = nextContext;
         return true;
@@ -687,6 +693,7 @@ describe('ReactCompositeComponent', function() {
     var instance = <Parent foo="abc" />;
     ReactTestUtils.renderIntoDocument(instance);
     instance.replaceProps({foo: "def"});
+    expect(actualComponentWillReceiveProps).toEqual({foo: 'def'});
     expect(actualShouldComponentUpdate).toEqual({foo: 'def'});
     expect(actualComponentWillUpdate).toEqual({foo: 'def'});
     expect(actualComponentDidUpdate).toEqual({foo: 'abc'});