Make reloadRefs realize when something has gone horribly wrong.

PBGitRepository.m

@@ -280,6 +280,11 @@ NSString* PBGitRepositoryErrorDomain = @"GitXErrorDomain";
 	else
 		sha = [PBGitSHA shaWithString:[components objectAtIndex:2]];
 
+	if(!sha) {
+		NSLog(@"sha was nil...? ref=%@, components=%@",ref,components);
+		return;
+	}
+
 	NSMutableArray* curRefs;
 	if ( (curRefs = [refs objectForKey:sha]) != nil )
 		[curRefs addObject:ref];
@@ -299,6 +304,13 @@ NSString* PBGitRepositoryErrorDomain = @"GitXErrorDomain";
 	NSString *output = [self outputForArguments:arguments];
 	NSArray *lines = [output componentsSeparatedByString:@"\n"];
 
+	if([output hasPrefix:@"fatal: "]) {
+		NSLog(@"Unable to read refs!");
+		NSLog(@"arguments=%@",arguments);
+		NSLog(@"output=%@",output);
+		@throw output;
+	}
+
 	for (NSString *line in lines) {
 		// If its an empty line, skip it (e.g. with empty repositories)
 		if ([line length] == 0)