Bolts doesnt infer failed tasks with NSError as a return type, always return failed tasks if needed

Author: flovilmart

Parse/Parse/PFObject.m

@@ -500,7 +500,7 @@ + (BFTask *)_deepSaveAsyncChildrenOfObject:(id)object withCurrentUser:(PFUser *)
                                 [object _objectWillSave];
                                 NSError *error;
                                 if (![object _checkSaveParametersWithCurrentUser:currentUser error:&error]) {
-                                    return error;
+                                    return [BFTask taskWithError:error];
                                 }
                                 command = [object _constructSaveCommandForChanges:[object unsavedChanges]
                                                                      sessionToken:sessionToken
@@ -626,7 +626,7 @@ + (BFTask *)_enqueueSaveEventuallyChildrenOfObject:(PFObject *)object currentUse
             // We do cycle-detection when building the list of objects passed to this
             // function, so this should never get called.  But we should check for it
             // anyway, so that we get an exception instead of an infinite loop.
-            PFPrecondition(current.count != 0, @"Unable to save a PFObject with a relation to a cycle.");
+            PFPreconditionWithTask(current.count != 0, @"Unable to save a PFObject with a relation to a cycle.");
 
             // If a lazy user is one of the objects in the array, resolve its laziness now and
             // remove it from the list of things to save.
@@ -1467,7 +1467,7 @@ - (BFTask *)saveAsync:(BFTask *)toAwait {
                 return [[childrenTask continueWithSuccessBlock:^id(BFTask *task) {
                     NSError *error;
                     if (![self _checkSaveParametersWithCurrentUser:currentUser error:&error]) {
-                        return error;
+                        return [BFTask taskWithError:error];
                     }
                     PFRESTCommand *command = [self _constructSaveCommandForChanges:changes
                                                                       sessionToken:sessionToken

Parse/Parse/PFUser.m

@@ -509,7 +509,7 @@ - (BFTask *)signUpAsync:(BFTask *)toAwait {
                 // self doesn't have any outstanding saves, so we can safely merge its operations
                 // into the current user.
 
-                PFPrecondition(!self._current, @"Attempt to merge currentUser with itself.");
+                PFPreconditionWithTask(!self._current, @"Attempt to merge currentUser with itself.");
 
                 @synchronized ([currentUser lock]) {
                     NSString *oldUsername = [currentUser.username copy];