Simplified WAL checkpointing

Author: wibosco

CoreDataMigration-Example/CoreData/Migration/CoreDataMigrationModel.swift

@@ -169,6 +169,16 @@ class CoreDataMigrationModel {
 
         return [step] + nextStep
     }
+    
+    // MARK: - Metadata
+    
+    static func migrationModelCompatibleWithStoreMetadata(_ metadata: [String : Any]) -> CoreDataMigrationModel? {
+        let compatibleMigrationModel = CoreDataMigrationModel.all.first {
+            $0.managedObjectModel().isConfiguration(withName: nil, compatibleWithStoreMetadata: metadata)
+        }
+        
+        return compatibleMigrationModel
+    }
 }
 
 // MARK: - Source

CoreDataMigration-Example/CoreData/Migration/CoreDataMigrator.swift

@@ -80,20 +80,12 @@ class CoreDataMigrator {
     // MARK: - WAL
 
     func forceWALCheckpointingForStore(at storeURL: URL) {
-        guard let metadata = NSPersistentStoreCoordinator.metadata(at: storeURL) else {
-            return
-        }
-        
-        let migrationVersionModel = CoreDataMigrationModel.all.first {
-            $0.managedObjectModel().isConfiguration(withName: nil, compatibleWithStoreMetadata: metadata)
-        }
-        
-        guard let currentCoreDataStoreMigrationVersionModel = migrationVersionModel else {
+        guard let metadata = NSPersistentStoreCoordinator.metadata(at: storeURL), let migrationModel = CoreDataMigrationModel.migrationModelCompatibleWithStoreMetadata(metadata)  else {
             return
         }
 
         do {
-            let model = currentCoreDataStoreMigrationVersionModel.managedObjectModel()
+            let model = migrationModel.managedObjectModel()
             let persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: model)
 
             let options = [NSSQLitePragmasOption: ["journal_mode": "DELETE"]]