From 87a6e938dad5ffeb9c0303c1cfacd00a762bb6d4 Mon Sep 17 00:00:00 2001
From: Richard <riscarrott@googlemail.com>
Date: Sat, 27 Feb 2016 17:05:53 +0000
Subject: [PATCH] Warn if props obj passed into createElement / cloneElement
 inherits from anything other than Object

---
 src/isomorphic/classic/element/ReactElement.js        | 10 ++++++++++
 .../classic/element/__tests__/ReactElement-test.js    | 11 +++++++++++
 .../element/__tests__/ReactElementClone-test.js       | 11 +++++++++++
 3 files changed, 32 insertions(+)

diff --git a/src/isomorphic/classic/element/ReactElement.js b/src/isomorphic/classic/element/ReactElement.js
index 379c81fc51bb2..d7f527139f72b 100644
--- a/src/isomorphic/classic/element/ReactElement.js
+++ b/src/isomorphic/classic/element/ReactElement.js
@@ -127,6 +127,10 @@ ReactElement.createElement = function(type, config, children) {
 
   if (config != null) {
     if (__DEV__) {
+      warning(
+        !(config.__proto__ != null && config.__proto__ !== Object.prototype),
+        'React.createElement(...): only instance properties will become props'
+      );
       ref = !config.hasOwnProperty('ref') ||
         Object.getOwnPropertyDescriptor(config, 'ref').get ? null : config.ref;
       key = !config.hasOwnProperty('key') ||
@@ -269,6 +273,12 @@ ReactElement.cloneElement = function(element, config, children) {
   var owner = element._owner;
 
   if (config != null) {
+    if (__DEV__) {
+      warning(
+        !(config.__proto__ != null && config.__proto__ !== Object.prototype),
+        'React.cloneElement(...): only instance properties will become props'
+      );
+    }
     if (config.ref !== undefined) {
       // Silently steal the ref from the parent.
       ref = config.ref;
diff --git a/src/isomorphic/classic/element/__tests__/ReactElement-test.js b/src/isomorphic/classic/element/__tests__/ReactElement-test.js
index 5760c8df7d6db..9e88ab13b2fe9 100644
--- a/src/isomorphic/classic/element/__tests__/ReactElement-test.js
+++ b/src/isomorphic/classic/element/__tests__/ReactElement-test.js
@@ -139,6 +139,17 @@ describe('ReactElement', function() {
     expect(element.props.foo).toBe(1);
   });
 
+  it('warns if the config object inherits from any type other than Object', function() {
+    spyOn(console, 'error');
+    React.createElement('div', {foo: 1});
+    expect(console.error).not.toHaveBeenCalled();
+    React.createElement('div', Object.create({foo: 1}));
+    expect(console.error.argsForCall.length).toBe(1);
+    expect(console.error.argsForCall[0][0]).toContain(
+      'React.createElement(...): only instance properties will become props'
+    );
+  });
+
   it('extracts key and ref from the config', function() {
     var element = React.createFactory(ComponentClass)({
       key: '12',
diff --git a/src/isomorphic/classic/element/__tests__/ReactElementClone-test.js b/src/isomorphic/classic/element/__tests__/ReactElementClone-test.js
index f4c5b4b761bd1..4979631ee47fd 100644
--- a/src/isomorphic/classic/element/__tests__/ReactElementClone-test.js
+++ b/src/isomorphic/classic/element/__tests__/ReactElementClone-test.js
@@ -66,6 +66,17 @@ describe('ReactElementClone', function() {
     expect(ReactDOM.findDOMNode(component).childNodes[0].className).toBe('xyz');
   });
 
+  it('should warn if the config object inherits from any type other than Object', function() {
+    spyOn(console, 'error');
+    React.cloneElement('div', {foo: 1});
+    expect(console.error).not.toHaveBeenCalled();
+    React.cloneElement('div', Object.create({foo: 1}));
+    expect(console.error.argsForCall.length).toBe(1);
+    expect(console.error.argsForCall[0][0]).toContain(
+      'React.cloneElement(...): only instance properties will become props'
+    );
+  });
+
   it('should keep the original ref if it is not overridden', function() {
     var Grandparent = React.createClass({
       render: function() {