Open Radar

 
Summary:
If a Core Data stack is set with the options NSSQLitePragmasOption: @{@"journal_mode": @"WAL"} and you need to run a migration that requires a Migration Manager, the resulting database will be corrupted and unreadable by Core Data.

Steps to Reproduce:
1. Create a project using the Core Data template.
2. Change the initialization to include these parameters when adding the NSPersistentStore
    NSDictionary *options = @{NSMigratePersistentStoresAutomaticallyOption:@YES,
                              NSInferMappingModelAutomaticallyOption:@YES,
                              NSSQLitePragmasOption: @{@"journal_mode": @"WAL"}
                              };
3. Run the app and add some records.
4. Add a new model version.
5. Add a new migration that uses a Migration Manager, and code it.
6. Run the new app.

Expected Results:
Perfectly functional app with migrated data.

Actual Results:
Empty DB and the app doesn't work any longer (can't add new records)

Notes:
I'm attaching a sample project. In there you can see four folders:
- v1: Initial version, almost as generated by the Xcode template.
- v1-Documents: The SQLite DB copied from the simulator after running the app.
- v2: A failing version of the app.
- v2-Workaround: A workaround that sets the journal_mode to DELETE, migrates, and reverts to WAL afterwards.