Mixin getDefaultProps before calling it

src/index.js

@@ -359,16 +359,19 @@ let findDOMNode = component => component && component.base || component;
 function F(){}
 
 function createClass(obj) {
-	let mixins = obj.mixins && collateMixins(obj.mixins);
+	obj = extend({}, obj);
 
 	function cl(props, context) {
 		extend(this, obj);
-		if (mixins) applyMixins(this, mixins);
 		Component.call(this, props, context, BYPASS_HOOK);
 		bindAll(this);
 		newComponentHook.call(this, props, context);
 	}
 
+	let mixins = obj.mixins && collateMixins(obj.mixins);
+	// We need to apply mixins here so that getDefaultProps is correctly mixed
+	if (mixins) applyMixins(obj, mixins);
+
 	if (obj.statics) {
 		extend(cl, obj.statics);
 	}

test/component.js

@@ -239,6 +239,45 @@ describe('components', () => {
 	});
 
 	describe("mixins", () => {
+		describe("getDefaultProps", () => {
+			it('should combine the results', () => {
+				const Foo = React.createClass({
+					mixins: [
+						{ getDefaultProps: () => ({ a: true }) },
+						{ getDefaultProps: () => ({ b: true }) }
+					],
+					getDefaultProps() {
+						return { c: true };
+					},
+					render() {
+						return <div />;
+					}
+				});
+
+				expect(Foo.defaultProps).to.eql({
+					a: true,
+					b: true,
+					c: true
+				});
+			});
+
+			it('should throw an error for duplicate keys', () => {
+				expect(() => {
+					const Foo = React.createClass({
+						mixins: [
+							{ getDefaultProps: () => ({ a: true }) }
+						],
+						getDefaultProps() {
+							return { a: true };
+						},
+						render() {
+							return <div />;
+						}
+					});
+				}).to.throw();
+			});
+		});
+
 		describe("getInitialState", () => {
 			it('should combine the results', () => {
 				const Foo = React.createClass({