chore($q): replace plain TypeError with minErr+TypeError in cyclical resolve check

Author: jeffbcross

docs/content/error/$q/qcycle.ngdoc

@@ -0,0 +1,23 @@
+@ngdoc error
+@name $q:qcycle
+@fullName Cannot resolve a promise with itself
+@description
+
+Occurs when resolving a promise with itself as the value, including returning the promise in a
+function passed to `then`. The A+ 1.1 spec mandates that this behavior throw a TypeError.
+https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
+
+```
+var promise = $q.defer().promise;
+
+//bad
+promise.then(function (val) {
+  //Cannot return self
+  return promise;
+});
+
+//good
+promise.then(function (val) {
+  return 'some other value';
+});
+```

src/ng/q.js

@@ -235,7 +235,7 @@ function $$QProvider() {
  * @returns {object} Promise manager.
  */
 function qFactory(nextTick, exceptionHandler) {
-  var $qMinErr = minErr('$q');
+  var $qMinErr = minErr('$q', TypeError);
   function callOnce(self, resolveFn, rejectFn) {
     var called = false;
     function wrap(fn) {
@@ -338,8 +338,16 @@ function qFactory(nextTick, exceptionHandler) {
   Deferred.prototype = {
     resolve: function(val) {
       if (this.promise.$$state.status) return;
-      if (val === this.promise) throw new TypeError('Cycle detected');
-      this.$$resolve(val);
+      if (val === this.promise) {
+        this.$$reject($qMinErr(
+          'qcycle',
+          "Expected promise to be resolved with value other than itself '{0}'",
+          val));
+      }
+      else {
+        this.$$resolve(val);
+      }
+
     },
 
     $$resolve: function(val) {

test/ng/qSpec.js

@@ -815,6 +815,20 @@ describe('q', function() {
       });
 
 
+      it('should complain if promise fulfilled with itself', function() {
+        var resolveSpy = jasmine.createSpy('resolve');
+        var rejectSpy = jasmine.createSpy('reject');
+        promise.then(resolveSpy, rejectSpy);
+        deferred.resolve(deferred.promise);
+        mockNextTick.flush();
+
+        expect(resolveSpy).not.toHaveBeenCalled();
+        expect(rejectSpy).toHaveBeenCalled();
+        expect(rejectSpy.calls[0].args[0].message).
+            toMatch(/\[\$q\:qcycle\] Expected promise to be resolved with value other than itself/);
+      });
+
+
       it('should do nothing if a promise was previously resolved', function() {
         promise.then(success(), error());
         expect(logStr()).toBe('');