Detecting a Lightweight Core Data Migration

Question

I\'m using Core Data\'s automatic lightweight migration successfully. However, when a particular entity gets created during a migration, I\'d like to populate it with some d

Answer 1

The accepted answer converted to Swift...

  var persistentStoreCoordinator: NSPersistentStoreCoordinator?
  var url: URL
  do {
    let sourceMetadata = try NSPersistentStoreCoordinator.metadataForPersistentStore(ofType: NSSQLiteStoreType, at: url, options: nil)
    if let destinationModel = persistentStoreCoordinator?.managedObjectModel {
      let compatibile = destinationModel.isConfiguration(withName: nil, compatibleWithStoreMetadata: sourceMetadata)
      if !compatibile {
        if let versionHashes = sourceMetadata["NSStoreModelVersionHashes"] as? [String: Any] {
          let sourceEntities = Set(versionHashes.keys)
          let destinationEntities = Set(destinationModel.entitiesByName.keys)

          var addedEntities = Set(destinationEntities)
          addedEntities.subtract(sourceEntities)

          var removedEntities = Set(sourceEntities)
          removedEntities.subtract(destinationEntities)
          let modelName = (destinationModel.versionIdentifiers.first as? String) ?? ""
          NSLog("Core Data requires a migration to model '\(modelName)'...\nAdded: \(addedEntities)\nRemoved: \(removedEntities)")
        }
      }
    }
  } catch {
            ...
  }