Track which lifecycle method we're in during DEV

Use this to detect setState inside of render instead of relying on
the owner.

src/renderers/shared/fiber/ReactFiberBeginWork.js

@@ -66,6 +66,7 @@ var invariant = require('invariant');
 
 if (__DEV__) {
   var ReactDebugCurrentFiber = require('ReactDebugCurrentFiber');
+  var ReactDebugLifeCycle = require('ReactDebugLifeCycle');
   var warning = require('warning');
 
   var warnedAboutStatelessRefs = {};
@@ -231,7 +232,11 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(
 
     if (__DEV__) {
       ReactCurrentOwner.current = workInProgress;
+      ReactDebugLifeCycle.current = workInProgress;
+      ReactDebugLifeCycle.phase = 'render';
       nextChildren = fn(nextProps, context);
+      ReactDebugLifeCycle.current = null;
+      ReactDebugLifeCycle.phase = null;
     } else {
       nextChildren = fn(nextProps, context);
     }
@@ -280,7 +285,16 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(
 
     // Rerender
     ReactCurrentOwner.current = workInProgress;
-    const nextChildren = instance.render();
+    let nextChildren;
+    if (__DEV__) {
+      ReactDebugLifeCycle.current = workInProgress;
+      ReactDebugLifeCycle.phase = 'render';
+      nextChildren = instance.render();
+      ReactDebugLifeCycle.current = null;
+      ReactDebugLifeCycle.phase = null;
+    } else {
+      nextChildren = instance.render();
+    }
     reconcileChildren(current, workInProgress, nextChildren);
     // Memoize props and state using the values we just used to render.
     // TODO: Restructure so we never read values from the instance.

src/renderers/shared/fiber/ReactFiberScheduler.js

@@ -89,6 +89,7 @@ if (__DEV__) {
   var warning = require('warning');
   var ReactFiberInstrumentation = require('ReactFiberInstrumentation');
   var ReactDebugCurrentFiber = require('ReactDebugCurrentFiber');
+  var ReactDebugLifeCycle = require('ReactDebugLifeCycle');
   var {
     isProcessingChildContext,
     onEndProcessingChildContext,
@@ -112,7 +113,7 @@ if (__DEV__) {
         false,
         'setState(...): Cannot call setState() inside getChildContext()',
       );
-    } else if (ReactCurrentOwner.current != null) {
+    } else if (ReactDebugLifeCycle.phase === 'render') {
       warning(
         false,
         'Cannot update during an existing state transition (such as within ' +
@@ -879,6 +880,8 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(config : HostConfig<T, P,
     ReactCurrentOwner.current = null;
     if (__DEV__) {
       ReactDebugCurrentFiber.current = null;
+      ReactDebugLifeCycle.current = null;
+      ReactDebugLifeCycle.phase = null;
       onEndProcessingChildContext();
     }
     // It is no longer valid because this unit of work failed.

src/renderers/shared/fiber/isomorphic/ReactDebugLifeCycle.js

@@ -0,0 +1,24 @@
+/**
+ * Copyright 2013-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule ReactDebugLifeCycle
+ * @flow
+ */
+
+'use strict';
+
+import type { Fiber } from 'ReactFiber';
+
+type LifeCyclePhase = 'render';
+
+const ReactDebugLifeCycle = {
+  current: (null : Fiber | null),
+  phase: (null : LifeCyclePhase | null),
+};
+
+module.exports = ReactDebugLifeCycle;