Merge pull request #1175 from not-an-aardvark/async-yield-handling

Ensure Promise.coroutine always handles yielded Promises asynchronously

src/generators.js

@@ -175,9 +175,13 @@ PromiseSpawn.prototype._continue = function (result) {
             this._yieldedPromise = maybePromise;
             maybePromise._proxy(this, null);
         } else if (BIT_FIELD_CHECK(IS_FULFILLED)) {
-            this._promiseFulfilled(maybePromise._value());
+            Promise._async.invoke(
+                this._promiseFulfilled, this, maybePromise._value()
+            );
         } else if (BIT_FIELD_CHECK(IS_REJECTED)) {
-            this._promiseRejected(maybePromise._reason());
+            Promise._async.invoke(
+                this._promiseRejected, this, maybePromise._reason()
+            );
         } else {
             this._promiseCancelled();
         }

test/mocha/generator.js

@@ -243,6 +243,40 @@ describe("Promise.coroutine", function() {
                 assert.equal(e, error);
             });
         });
+
+        specify("when they are already fulfilled, the yielded value should be returned asynchronously", function(){
+            var value;
+
+            var promise = Promise.coroutine(function*(){
+                yield Promise.resolve();
+                value = 2;
+            })();
+
+            value = 1;
+
+            return promise.then(function(){
+                assert.equal(value, 2);
+            });
+        });
+
+        specify("when they are already rejected, the yielded reason should be thrown asynchronously", function(){
+            var value;
+
+            var promise = Promise.coroutine(function*(){
+                try {
+                    yield Promise.reject();
+                }
+                catch (e) {
+                    value = 2;
+                }
+            })();
+
+            value = 1;
+
+            return promise.then(function(){
+                assert.equal(value, 2);
+            });
+        });
     });
 
     describe("yield loop", function(){