Merge pull request #8883 from bn-dignitas/8843-fix-request-memory-ret…

…ention

#8843 Clean up request data references

CONTRIBUTORS.md

@@ -259,3 +259,4 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 - [Jakub Vrana](https://github.com/vrana)
 - [Edvinas Pranka](https://github.com/epranka)
 - [James Bromwell](https://github.com/thw0rted)
+- [Brandon Nguyen](https://github.com/bn-dignitas)

Source/Core/RequestScheduler.js

@@ -182,6 +182,8 @@ function getRequestReceivedFunction(request) {
     requestCompletedEvent.raiseEvent();
     request.state = RequestState.RECEIVED;
     request.deferred.resolve(results);
+    // explicitly set to undefined to ensure GC of request response data. See #8843
+    request.deferred = undefined;
   };
 }
 
@@ -218,7 +220,12 @@ function cancelRequest(request) {
   var active = request.state === RequestState.ACTIVE;
   request.state = RequestState.CANCELLED;
   ++statistics.numberOfCancelledRequests;
-  request.deferred.reject();
+  // check that deferred has not been cleared since cancelRequest can be called
+  // on a finished request, e.g. by clearForSpecs during tests
+  if (defined(request.deferred)) {
+    request.deferred.reject();
+    request.deferred = undefined;
+  }
 
   if (active) {
     --statistics.numberOfActiveRequests;

Source/Core/Resource.js

@@ -1367,9 +1367,12 @@ Resource.prototype._makeRequest = function (options) {
 
   return promise
     .then(function (data) {
+      // explicitly set to undefined to ensure GC of request response data. See #8843
+      request.cancelFunction = undefined;
       return data;
     })
     .otherwise(function (e) {
+      request.cancelFunction = undefined;
       if (request.state !== RequestState.FAILED) {
         return when.reject(e);
       }