Merge pull request #5320 from drdelambre/overwrite_props

Overwriting of mutated props in constructor

src/renderers/shared/reconciler/ReactCompositeComponent.js

@@ -199,7 +199,7 @@ var ReactCompositeComponentMixin = {
 
     // These should be set up in the constructor, but as a convenience for
     // simpler class abstractions, we set them up after the fact.
-    inst.props = publicProps;
+    inst.props = inst.props || publicProps;
     inst.context = publicContext;
     inst.refs = emptyObject;
     inst.updater = ReactUpdateQueue;

src/renderers/shared/reconciler/__tests__/ReactCompositeComponent-test.js

@@ -1241,4 +1241,39 @@ describe('ReactCompositeComponent', function() {
 
   });
 
+  it('should not overwrite mutated properties', function() {
+    class Moo extends React.Component {
+      render() {
+        return <span />;
+      }
+    }
+    Moo.defaultProps = { idx: 'moo' };
+
+    function Foo(props) {
+      var _props = { idx: this.constructor.defaultProps.idx + '?' };
+
+      React.Component.call(this, _props);
+    }
+    Foo.prototype = Object.create(React.Component.prototype, {
+      constructor: {
+        value: Foo,
+      },
+    });
+    Foo.prototype.render = function() {
+      return <span />;
+    };
+    Foo.defaultProps = { idx: 'foo' };
+
+    class Bar extends Foo {}
+    Bar.defaultProps = { idx: 'bar' };
+
+    var moo = ReactTestUtils.renderIntoDocument(<Moo />);
+    expect(moo.props.idx).toBe('moo');
+
+    var foo = ReactTestUtils.renderIntoDocument(<Foo />);
+    expect(foo.props.idx).toBe('foo?');
+
+    var bar = ReactTestUtils.renderIntoDocument(<Bar />);
+    expect(bar.props.idx).toBe('bar?');
+  });
 });