Composite component throws on attaching ref to stateless component #4939

src/renderers/shared/reconciler/ReactCompositeComponent.js

@@ -808,8 +808,10 @@ var ReactCompositeComponentMixin = {
   attachRef: function(ref, component) {
     var inst = this.getPublicInstance();
     invariant(inst != null, 'Stateless function components cannot have refs.');
+    var componentInstance = component.getPublicInstance();
+    invariant(componentInstance != null, 'Stateless function components cannot be given refs.');
     var refs = inst.refs === emptyObject ? (inst.refs = {}) : inst.refs;
-    refs[ref] = component.getPublicInstance();
+    refs[ref] = componentInstance;
   },
 
   /**

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

@@ -125,6 +125,20 @@ describe('ReactStatelessComponent', function() {
     );
   });
 
+  it('should throw when given a ref', function() {
+    var Parent = React.createClass({
+      render: function() {
+        return <StatelessComponent name="A" ref="stateless"/>;
+      },
+    });
+
+    expect(function() {
+      ReactTestUtils.renderIntoDocument(<Parent/>);
+    }).toThrow(
+      'Invariant Violation: Stateless function components cannot be given refs.'
+    );
+  });
+
   it('should provide a null ref', function() {
     function Child() {
       return <div />;