Prevent resolving a promise twice.

lib/rsvp/promise.js

@@ -78,6 +78,9 @@ var invokeCallback = function(type, promise, callback, event) {
   var hasCallback = isFunction(callback),
       value, error, succeeded, failed;
 
+  if (promise.isFulfilled) { return; }
+  if (promise.isRejected) { return; }
+
   if (hasCallback) {
     try {
       value = callback(event.detail);
@@ -207,6 +210,8 @@ function handleThenable(promise, value) {
 
 function fulfill(promise, value) {
   config.async(function() {
+    if (promise.isFulfilled) { return; }
+    if (promise.isRejected) { return; }
     promise.trigger('promise:resolved', { detail: value });
     promise.isFulfilled = true;
     promise.fulfillmentValue = value;
@@ -215,6 +220,8 @@ function fulfill(promise, value) {
 
 function reject(promise, value) {
   config.async(function() {
+    if (promise.isFulfilled) { return; }
+    if (promise.isRejected) { return; }
     promise.trigger('promise:failed', { detail: value });
     promise.isRejected = true;
     promise.rejectedReason = value;

test/tests/extension_test.js

@@ -1489,6 +1489,50 @@ describe("`cancel` on promise created by then", function () {
     assert.equal(typeof promise.cancel, "function");
   });
 
+  it('should stop parent fulFillment propagation', function (done) {
+    var promise = new RSVP.resolve(1),
+      promise2 = promise.then();
+    promise2.cancel("Foo");
+
+    setTimeout(function() {
+      assert.equal(promise2.isRejected, true);
+      assert.equal(promise2.isFulfilled, undefined);
+      assert(promise2.rejectedReason instanceof RSVP.CancellationError);
+      done();
+    }, 20);
+  });
+
+  it('should stop parent rejection propagation', function (done) {
+    var reject_count = 0,
+      promise = new RSVP.reject(1),
+      promise2 = promise.fail(function () {reject_count += 1;});
+    promise2.cancel("Foo");
+
+    setTimeout(function() {
+      assert.equal(promise2.isRejected, true);
+      assert.equal(promise2.isFulfilled, undefined);
+      assert(promise2.rejectedReason instanceof RSVP.CancellationError);
+      assert.equal(reject_count, 1);
+      done();
+    }, 20);
+  });
+
+  it('should not be callable twice', function (done) {
+    var reject_count = 0,
+      promise = new RSVP.reject(1),
+      promise2 = promise.fail(function () {reject_count += 1;});
+    promise2.cancel("Foo");
+    promise2.cancel("Bar");
+
+    setTimeout(function() {
+      assert.equal(promise2.isRejected, true);
+      assert.equal(promise2.isFulfilled, undefined);
+      assert(promise2.rejectedReason instanceof RSVP.CancellationError);
+      assert.equal(reject_count, 1);
+      done();
+    }, 20);
+  });
+
   it('should cancel the pending fulfilled promise', function (done) {
     var cancel_called = false,
       promise = new RSVP.Promise(function (resolve) {resolve();}),
@@ -1804,13 +1848,12 @@ describe("`RSVP.Queue`", function () {
       assert(promise instanceof RSVP.Promise);
     });
 
-    it('should work without `new`', function(done) {
+    it('should work without `new`', function() {
       var promise = RSVP.Queue()
         .push(function() { return 'value'; });
 
       promise.then(function(value) {
         assert.equal(value, 'value');
-        done();
       });
     });
   });