Migrating, but still getting crash on 'RLMException', reason: 'Migration is required

问题:

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {      // Realm, 1th thing     {         RLMRealmConfiguration *config = [RLMRealmConfiguration defaultConfiguration];         config.schemaVersion = 2;         config.migrationBlock = ^(RLMMigration *migration, uint64_t oldSchemaVersion) {          };         config.objectClasses = @[[User class], [UsersMenuItem class]];         [RLMRealm migrateRealm:config];     }      ... } 

I did add a property to the user object, the docu says the new realm should automigrate, but i get a crash

 *** Terminating app due to uncaught exception 'RLMException', reason: 'Migration is required for object type 'User' due to the following errors: - Property 'realtedMenuItems' has been added to latest object model.' *** First throw call stack: (0x1838ad900 0x182f1bf80 0x10015db3c 0x10014aa60 0x100149a70 0x100116500 0x1000a6488 0x1000f1664 0x1885a00c0 0x18859fcc4 0x100039568 0x188615704 0x188844130 0x1888484b8 0x1888455c0 0x184e63790 0x184e63b10 0x183864efc 0x183864990 0x183862690 0x183791680 0x18860e580 0x188608d90 0x1000b7430 0x1833328b8) libc++abi.dylib: terminating with uncaught exception of type NSException 

Version: 0.95

Note: When i updated to 0.96 i get

 *** Terminating app due to uncaught exception 'RLMException', reason: 'Provided schema version 0 is less than last set version 3.' *** First throw call stack: 

回答1:

Looks like adding

[RLMRealmConfiguration setDefaultConfiguration:config]; 

solved the issue, although not sure why

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {      // Realm     {         RLMRealmConfiguration *config = [RLMRealmConfiguration defaultConfiguration];         config.schemaVersion = 4;         config.migrationBlock = ^(RLMMigration *migration, uint64_t oldSchemaVersion) {          };         NSError * error = [RLMRealm migrateRealm:config];         if (error) {             NSLog(@"Error migrating realm %@", error);         }         [RLMRealmConfiguration setDefaultConfiguration:config];     } 

回答2:

RLMRealmConfiguration acts as value object. Modifications applied to it, don't automatically take effect to the defaultConfiguration. You can only retrieve a copy of it. That means you have to user the setter to share you modifications back.

文章来源: Migrating, but still getting crash on 'RLMException', reason: 'Migration is required