From fd43666ca827e2b72971836557b9a2ff661f0502 Mon Sep 17 00:00:00 2001
From: Jim <jsproch@fb.com>
Date: Mon, 25 Apr 2016 12:36:20 -0700
Subject: [PATCH] ComponentWillUnmount should only ever be invoked once

---
 .../reconciler/ReactCompositeComponent.js     |  6 ++-
 .../__tests__/ReactCompositeComponent-test.js | 41 +++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/renderers/shared/reconciler/ReactCompositeComponent.js b/src/renderers/shared/reconciler/ReactCompositeComponent.js
index 907de98089ec0..d6ea8b123312f 100644
--- a/src/renderers/shared/reconciler/ReactCompositeComponent.js
+++ b/src/renderers/shared/reconciler/ReactCompositeComponent.js
@@ -132,6 +132,9 @@ var ReactCompositeComponentMixin = {
 
     // See ReactUpdates and ReactUpdateQueue.
     this._pendingCallbacks = null;
+
+    // ComponentWillUnmount shall only be called once
+    this._calledComponentWillUnmount = false;
   },
 
   /**
@@ -405,7 +408,8 @@ var ReactCompositeComponentMixin = {
     }
     var inst = this._instance;
 
-    if (inst.componentWillUnmount) {
+    if (inst.componentWillUnmount && !inst._calledComponentWillUnmount) {
+      inst._calledComponentWillUnmount = true;
       if (safely) {
         var name = this.getName() + '.componentWillUnmount()';
         ReactErrorUtils.invokeGuardedCallback(name, inst.componentWillUnmount.bind(inst));
diff --git a/src/renderers/shared/reconciler/__tests__/ReactCompositeComponent-test.js b/src/renderers/shared/reconciler/__tests__/ReactCompositeComponent-test.js
index c33fb33b25382..5568ae33931ba 100644
--- a/src/renderers/shared/reconciler/__tests__/ReactCompositeComponent-test.js
+++ b/src/renderers/shared/reconciler/__tests__/ReactCompositeComponent-test.js
@@ -1303,4 +1303,45 @@ describe('ReactCompositeComponent', function() {
 
   });
 
+  it('should only call componentWillUnmount once', function() {
+    var app;
+    var count = 0;
+
+    class App extends React.Component {
+      render() {
+        if (this.props.stage === 1) {
+          return <UnunmountableComponent />;
+        } else {
+          return null;
+        }
+      }
+    }
+
+    class UnunmountableComponent extends React.Component {
+      componentWillUnmount() {
+        app.setState({});
+        count++;
+        throw Error('always fails');
+      }
+
+      render() {
+        return <div>Hello {this.props.name}</div>;
+      }
+    }
+
+    var container = document.createElement('div');
+
+    var setRef = (ref) => {
+      if (ref) {
+        app = ref;
+      }
+    };
+
+    expect(function() {
+      ReactDOM.render(<App ref={setRef} stage={1} />, container);
+      ReactDOM.render(<App ref={setRef} stage={2} />, container);
+    }).toThrow();
+    expect(count).toBe(1);
+  });
+
 });