Simplified extensions by reduces dependencies

Author: wibosco

CoreDataMigration-Example/CoreData/Migration/CoreDataMigrationVersion.swift

@@ -18,7 +18,11 @@ enum CoreDataMigrationVersion: String, CaseIterable {
     // MARK: - Latest
 
     static var latest: CoreDataMigrationVersion {
-        return allCases.last!
+        guard let latest = allCases.last else {
+            fatalError("no model versions found")
+        }
+        
+        return latest
     }
 
     // MARK: - Migration
@@ -35,16 +39,4 @@ enum CoreDataMigrationVersion: String, CaseIterable {
             return nil
         }
     }
-    
-    // MARK: - Compatible
-    
-    static func compatibleVersionForStoreMetadata(_ metadata: [String : Any]) -> CoreDataMigrationVersion? {
-        let compatibleVersion = CoreDataMigrationVersion.allCases.first {
-            let model = NSManagedObjectModel.managedObjectModel(forResource: $0.rawValue)
-            
-            return model.isConfiguration(withName: nil, compatibleWithStoreMetadata: metadata)
-        }
-        
-        return compatibleVersion
-    }
 }

CoreDataMigration-Example/CoreData/Migration/CoreDataMigrator.swift

@@ -114,3 +114,18 @@ class CoreDataMigrator: CoreDataMigratorProtocol {
         }
     }
 }
+
+private extension CoreDataMigrationVersion {
+    
+    // MARK: - Compatible
+    
+    static func compatibleVersionForStoreMetadata(_ metadata: [String : Any]) -> CoreDataMigrationVersion? {
+        let compatibleVersion = CoreDataMigrationVersion.allCases.first {
+            let model = NSManagedObjectModel.managedObjectModel(forResource: $0.rawValue)
+            
+            return model.isConfiguration(withName: nil, compatibleWithStoreMetadata: metadata)
+        }
+        
+        return compatibleVersion
+    }
+}

CoreDataMigration-Example/Extensions/NSManagedObjectModel/NSManagedObjectModel+Compatible.swift

@@ -14,10 +14,7 @@ extension NSManagedObjectModel {
     // MARK: - Compatible
 
     static func compatibleModelForStoreMetadata(_ metadata: [String : Any]) -> NSManagedObjectModel? {
-        guard let compatibleModelVersion = CoreDataMigrationVersion.compatibleVersionForStoreMetadata(metadata) else {
-            return nil
-        }
-        
-        return NSManagedObjectModel.managedObjectModel(forResource: compatibleModelVersion.rawValue)
+        let mainBundle = Bundle.main
+        return NSManagedObjectModel.mergedModel(from: [mainBundle], forStoreMetadata: metadata)
     }
 }