Check if notes reference exists before pushing it

Author: slavikus

ObjectiveGit/GTRepository+RemoteOperations.m

@@ -204,7 +204,11 @@ - (BOOL)pushBranches:(NSArray *)branches toRemote:(GTRemote *)remote withOptions
 
 	// Also push the notes reference, if needed.
 	if (referenceName != nil) {
-		[refspecs addObject:[NSString stringWithFormat:@"%@:%@", referenceName, referenceName]];
+		// but check whether the reference exists for the repo, otherwise, our push will fail
+		GTReference* notesRef = [self lookUpReferenceWithName:referenceName error:nil];
+		
+		if (notesRef != nil)
+			[refspecs addObject:[NSString stringWithFormat:@"%@:%@", referenceName, referenceName]];
 	}
 
 	return [self pushRefspecs:refspecs toRemote:remote withOptions:options error:error progress:progressBlock];
@@ -219,6 +223,11 @@ - (BOOL)pushNotes:(NSString *)noteRef toRemote:(GTRemote *)remote withOptions:(N
 		if (noteRef == nil) return NO;
 	}
 
+	GTReference* notesReference = [self lookUpReferenceWithName:noteRef error:error];
+	
+	if (notesReference == nil)
+		return NO;	// error will be pre-filled with the lookUpReferenceWithName call
+	
 	return [self pushRefspecs:@[[NSString stringWithFormat:@"%@:%@", noteRef, noteRef]] toRemote:remote withOptions:options error:error progress:progressBlock];
 }