fix($http): JSON parse failure

Fixes angular#15695

Author: chirag64

docs/content/error/$http/baddata.ngdoc

@@ -3,11 +3,14 @@
 @fullName Bad JSON Data
 @description
 
-This error occurs when the data parameter passed to the {@link ng.$http `defaultHttpResponseTransform`} service is not a valid JSON object.
-`defaultHttpResponseTransform` expects the first parameter as a valid JSON object if the second parameter of headers specifies a Content-Type of JSON.
+The default @{link ng$http#default-transformations `transformResponse`} will try to parse the
+response as JSON if the `Content-Type` header is `application/json` or the response looks like a
+valid JSON-stringified object or array.
+This error occurs when that data is not a valid JSON object.
 
-The error message should provide additional context such as the actual value of the parameter that was received.
+The error message should provide additional context such as the actual response.
 
-To resolve this error, make sure you pass a valid JSON data object to `defaultHttpResponseTransform`.
+To resolve this error, make sure you pass a valid JSON data object to `transformResponse`.
 
-For more information, see the {@link ng.$http `defaultHttpResponseTransform`} service API documentation.
+For more information, see the {@link ng$http#default-transformations `transformResponse`} service
+API documentation.

src/ng/http.js

@@ -141,7 +141,8 @@ function defaultHttpResponseTransform(data, headers) {
         try {
           data = fromJson(tempData);
         } catch (e) {
-          throw minErr('$http')('baddata', 'Data must be a valid JSON object. Received: {0}', data);
+          throw $httpMinErr('baddata', 'Data must be a valid JSON object. Received: "{0}". ' +
+          'Error occurred: "{1}"', data, e);
         }
       }
     }

test/ng/httpSpec.js

@@ -1442,6 +1442,17 @@ describe('$http', function() {
           expect(callback.calls.argsFor(1)[0]).toBe(null);
           expect(callback.calls.argsFor(2)[0]).toBe('');
         });
+
+        it('should return JSON data with error message if JSON is invalid', function() {
+          var errCallback = jasmine.createSpy('error');
+          $httpBackend.expect('GET', '/url').respond('{abcd}', {'Content-Type': 'application/json'});
+            $http({method: 'GET', url: '/url'}).then(callback).catch(errCallback);
+            $httpBackend.flush();
+
+            expect(callback).not.toHaveBeenCalled();
+            expect(errCallback).toHaveBeenCalledOnce();
+            expect(errCallback.calls.mostRecent().args[0]).toEqualMinErr('$http', 'baddata');
+        });
       });
     });