目标C奇怪如果（NO）条件

Question

我在Objective C中遇到了一个奇怪的问题。请看下面的代码。

+(BOOL)isWritableCopyofAppConfig{

BOOL response = false;

NSURL *urlConfig = [NSURL URLWithString:APP_CONFIG_PATH];
NSData *dataReturn = [NSData dataWithContentsOfURL:urlConfig];
NSFileManager *fileMgr = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0]stringByAppendingPathComponent:@"AppConfig.plist"];

if (dataReturn != nil ){
   // It always goes here
}
else{
   // Never reach here.
}

return response;
}

即使我将上述if条件更改为以下内容：

if (NO){
   // It always goes here even if there is NO.
}
else{
   // Never reach here.
}

我尝试清理项目我试过其他的东西，比如直接比较NO == YES仍然会进入第一个区块。

有谁知道如何解决这个或这个行为是什么？

编辑：整个代码

+(BOOL)isWritableCopyofAppConfig{

BOOL response = false;

NSURL *urlConfig = [NSURL URLWithString:APP_CONFIG_PATH];
NSData *dataReturn = [NSData dataWithContentsOfURL:urlConfig];
NSFileManager *fileMgr = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0]stringByAppendingPathComponent:@"AppConfig.plist"];

if (NO){
    if (filePath != nil){
        response = [dataReturn writeToFile:filePath atomically:YES];
    }
}
else{
    NSString *resourcePath = [[NSBundle mainBundle] pathForResource:@"AppConfig" ofType:@".plist"];
    [fileMgr copyItemAtPath:resourcePath toPath:filePath error:nil];
}

return response;

}

它是一个类方法（从AppDelegate.m调用）：

 AppConfigHandler.isWritableCopyofAppConfig();

编辑：调试器的屏幕截图