checking for nil before sending message

Question

I am having this issue in Xcode 6. It is fine if I use this in Xcode 5 or below.

Objects are automatically instantiated even though it's nil and can't check nil.

NSString *userID = [DataManager sharedInstance].currentUser.userId;

if (!userID) {
    userID = @"user";
}
[userInfo setObject:userID forKey:LogDataUserIDKey];

That's what I am doing and I am getting EXE_BAD_ACCESS(code=1, address=0x443b800c) at the last line. userID is instantiated as my attached screenshot. How can I check whether userID is nil. I am lost. Please advise. enter image description here

You do realize that Xcode is just an IDE? This question has nothing whatsoever to do with Xcode. — dandan78, Nov 26 '14 at 07:49
have tried to log the userID before setting it in dictionary and after the if statement? — iHulk, Nov 26 '14 at 07:54
If I put `NSLog(@"userID : %@", userID);` right after `userID` assignment, I also got `EXC_BAD_ACCESS` — Min Soe, Nov 26 '14 at 08:03
@dandan78 i am having that issue only in Xcode 6. Not in Xcode 5. That's why I put Xcode 6. Xcode is just an IDE i know. but different version of xcode is different version of compiler, right? — Min Soe, Nov 26 '14 at 08:04
@MinSoe Ok, then that's important info that should've been included in your question. Always include all relevant information. — dandan78, Nov 26 '14 at 08:08
@dandan78 ya? you removed it because you think it's irrelevant. — Min Soe, Nov 26 '14 at 08:18
@MinSoe You weren't clear. You never said it worked fine in the previous version of Xcode. — dandan78, Nov 26 '14 at 08:23
can you tell me what object is your [DataManager sharedInstance] class method returning as your log says that self is representing the DataManager class. But you say, it is giving you the compile time error when replacing [DataManager sharedInstance] with self? — iHulk, Nov 26 '14 at 09:13
@iHulk this is what inside DataManager's sharedInstance `+ (DataManager*)sharedInstance{ @synchronized(self){ if(!_sharedInstance){ _sharedInstance = [[self alloc]init]; } return _sharedInstance; } return nil; }` — Min Soe, Nov 26 '14 at 09:16
Have you tried debugging with NSZombies? http://stackoverflow.com/a/4917557/909655 — Mats, Nov 26 '14 at 10:18

Min Soe · Accepted Answer · 2014-11-27T06:15:58.697

0

OK. I am able to fix the issue. It is because inside this User object which is [DataManager sharedInstance].currentUser, userId is declared as both instance variable and property.

@interface User : NSObject <NSCopying>{
NSString *userId; // instance variable
}
@property (nonatomic, retain) NSString * userId;

So, by removing the instance variable declaration and it fixed the issue.

@interface User : NSObject <NSCopying>
@property (nonatomic, retain) NSString * userId;

But, I am not sure why. You guys have any idea?

edited Nov 27 '14 at 06:15

answered Nov 27 '14 at 02:49

Min Soe

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why are you declaring both the ivar and property? – Nick Nov 27 '14 at 02:56
@Nick umm, it was already like that. I inherited the code from someone. – Min Soe Nov 27 '14 at 04:16
I'd delete the ivar declaration, and allow xcode to automatically synthesize the property to `_userId`. It avoids the name conflict and you can still get to the ivar if you need to. There is a good chance one of those declarations was in error. – Nick Nov 27 '14 at 04:25
@Nick yes. that's what i did. I removed the ivar and it's solved the problem. – Min Soe Nov 27 '14 at 06:02

checking for nil before sending message

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