Resolve source entity and managed object attributes by name

Addresses #300 – see it for details. Also improves the use of whitespace consistency across the `CustomSchemaMappingProvider.swift` and uses method names for `cs_resolve…` over `cs_resolved…` for better alignment with [Swift API Design Guidelines](https://swift.org/documentation/api-design-guidelines).

Sources/CustomSchemaMappingProvider.swift

@@ -121,7 +121,7 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
         
         // MARK: Equatable
         
-        public static func == (lhs: CustomMapping, rhs: CustomMapping) -> Bool {
+        public static func ==(lhs: CustomMapping, rhs: CustomMapping) -> Bool {
             
             switch (lhs, rhs) {
             
@@ -324,7 +324,7 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
     
     // MARK: Equatable
     
-    public static func == (lhs: CustomSchemaMappingProvider, rhs: CustomSchemaMappingProvider) -> Bool {
+    public static func ==(lhs: CustomSchemaMappingProvider, rhs: CustomSchemaMappingProvider) -> Bool {
         
         return lhs.sourceVersion == rhs.sourceVersion
             && lhs.destinationVersion == rhs.destinationVersion
@@ -422,8 +422,8 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
             entityMapping.sourceExpression = expression(forSource: sourceEntity)
             entityMapping.attributeMappings = autoreleasepool { () -> [NSPropertyMapping] in
                 
-                let sourceAttributes = sourceEntity.cs_resolvedAttributeRenamingIdentities()
-                let destinationAttributes = destinationEntity.cs_resolvedAttributeRenamingIdentities()
+                let sourceAttributes = sourceEntity.cs_resolveAttributeNames()
+                let destinationAttributes = destinationEntity.cs_resolveAttributeRenamingIdentities()
                 
                 var attributeMappings: [NSPropertyMapping] = []
                 for (renamingIdentifier, destination) in destinationAttributes {
@@ -439,8 +439,8 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
             }
             entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
                 
-                let sourceRelationships = sourceEntity.cs_resolvedRelationshipRenamingIdentities()
-                let destinationRelationships = destinationEntity.cs_resolvedRelationshipRenamingIdentities()
+                let sourceRelationships = sourceEntity.cs_resolveRelationshipNames()
+                let destinationRelationships = destinationEntity.cs_resolveRelationshipRenamingIdentities()
                 var relationshipMappings: [NSPropertyMapping] = []
                 for (renamingIdentifier, destination) in destinationRelationships {
                     
@@ -476,8 +476,8 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
             ]
             autoreleasepool {
                 
-                let sourceAttributes = sourceEntity.cs_resolvedAttributeRenamingIdentities()
-                let destinationAttributes = destinationEntity.cs_resolvedAttributeRenamingIdentities()
+                let sourceAttributes = sourceEntity.cs_resolveAttributeNames()
+                let destinationAttributes = destinationEntity.cs_resolveAttributeRenamingIdentities()
                 
                 let transformedRenamingIdentifiers = Set(destinationAttributes.keys)
                     .intersection(sourceAttributes.keys)
@@ -493,8 +493,8 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
             }
             entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
                 
-                let sourceRelationships = sourceEntity.cs_resolvedRelationshipRenamingIdentities()
-                let destinationRelationships = destinationEntity.cs_resolvedRelationshipRenamingIdentities()
+                let sourceRelationships = sourceEntity.cs_resolveRelationshipNames()
+                let destinationRelationships = destinationEntity.cs_resolveRelationshipRenamingIdentities()
                 let transformedRenamingIdentifiers = Set(destinationRelationships.keys)
                     .intersection(sourceRelationships.keys)
                 
@@ -593,9 +593,9 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
         var allMappedSourceKeys: [KeyPathString: KeyPathString] = [:]
         var allMappedDestinationKeys: [KeyPathString: KeyPathString] = [:]
         
-        let sourceRenamingIdentifiers = sourceModel.cs_resolvedRenamingIdentities()
+        let sourceRenamingIdentifiers = sourceModel.cs_resolveNames()
         let sourceEntityNames = sourceModel.entitiesByName
-        let destinationRenamingIdentifiers = destinationModel.cs_resolvedRenamingIdentities()
+        let destinationRenamingIdentifiers = destinationModel.cs_resolveRenamingIdentities()
         let destinationEntityNames = destinationModel.entitiesByName
         
         let removedRenamingIdentifiers = Set(sourceRenamingIdentifiers.keys)
@@ -699,8 +699,7 @@ public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
                             destinationEntity: destinationEntityName
                         )
                     )
-                }
-                else {
+                } else {
                     
                     transformMappings.insert(
                         .transformEntity(

Sources/NSEntityDescription+Migration.swift

@@ -32,24 +32,30 @@ import Foundation
 internal extension NSEntityDescription {
     
     @nonobjc
-    internal func cs_resolvedAttributeRenamingIdentities() -> [String: (attribute: NSAttributeDescription, versionHash: Data)] {
-        
-        var mapping: [String: (attribute: NSAttributeDescription, versionHash: Data)] = [:]
-        for (attributeName, attributeDescription) in self.attributesByName {
-            
-            mapping[attributeDescription.renamingIdentifier ?? attributeName] = (attributeDescription, attributeDescription.versionHash)
-        }
-        return mapping
+    internal func cs_resolveAttributeNames() -> [String: (attribute: NSAttributeDescription, versionHash: Data)] {
+        return self.attributesByName.reduce(into: [:], { (result, attribute: (name: String, description: NSAttributeDescription)) in
+            result[attribute.name] = (attribute.description, attribute.description.versionHash)
+        })
     }
     
     @nonobjc
-    internal func cs_resolvedRelationshipRenamingIdentities() -> [String: (relationship: NSRelationshipDescription, versionHash: Data)] {
+    internal func cs_resolveAttributeRenamingIdentities() -> [String: (attribute: NSAttributeDescription, versionHash: Data)] {
+        return self.attributesByName.reduce(into: [:], { (result, attribute: (name: String, description: NSAttributeDescription)) in
+            result[attribute.description.renamingIdentifier ?? attribute.name] = (attribute.description, attribute.description.versionHash)
+        })
+    }
     
-        var mapping: [String: (relationship: NSRelationshipDescription, versionHash: Data)] = [:]
-        for (relationshipName, relationshipDescription) in self.relationshipsByName {
+    @nonobjc
+    internal func cs_resolveRelationshipNames() -> [String: (relationship: NSRelationshipDescription, versionHash: Data)] {
+        return self.relationshipsByName.reduce(into: [:], { (result, relationship: (name: String, description: NSRelationshipDescription)) in
+            result[relationship.name] = (relationship.description, relationship.description.versionHash)
+        })
+    }
     
-            mapping[relationshipDescription.renamingIdentifier ?? relationshipName] = (relationshipDescription, relationshipDescription.versionHash)
-        }
-        return mapping
+    @nonobjc
+    internal func cs_resolveRelationshipRenamingIdentities() -> [String: (relationship: NSRelationshipDescription, versionHash: Data)] {
+        return self.relationshipsByName.reduce(into: [:], { (result, relationship: (name: String, description: NSRelationshipDescription)) in
+            result[relationship.description.renamingIdentifier ?? relationship.name] = (relationship.description, relationship.description.versionHash)
+        })
     }
 }

Sources/NSManagedObjectModel+Migration.swift

@@ -32,13 +32,16 @@ import Foundation
 internal extension NSManagedObjectModel {
     
     @nonobjc
-    internal func cs_resolvedRenamingIdentities() -> [String: (entity: NSEntityDescription, versionHash: Data)] {
+    internal func cs_resolveNames() -> [String: (entity: NSEntityDescription, versionHash: Data)] {
+        return self.entitiesByName.reduce(into: [:], { (result, entity: (name: String, description: NSEntityDescription)) in
+            result[entity.name] = (entity.description, entity.description.versionHash)
+        })
+    }
     
-        var mapping: [String: (entity: NSEntityDescription, versionHash: Data)] = [:]
-        for (entityName, entityDescription) in self.entitiesByName {
-            
-            mapping[entityDescription.renamingIdentifier ?? entityName] = (entityDescription, entityDescription.versionHash)
-        }
-        return mapping
+    @nonobjc
+    internal func cs_resolveRenamingIdentities() -> [String: (entity: NSEntityDescription, versionHash: Data)] {
+        return self.entitiesByName.reduce(into: [:], { (result, entity: (name: String, description: NSEntityDescription)) in
+            result[entity.description.renamingIdentifier ?? entity.name] = (entity.description, entity.description.versionHash)
+        })
     }
 }