fix demo app warnings

CoreStore.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
     s.name = "CoreStore"
-    s.version = "4.0.0"
+    s.version = "4.0.2"
     s.license = "MIT"
     s.summary = "Unleashing the real power of Core Data with the elegance and safety of Swift"
     s.homepage = "https://github.com/JohnEstropia/CoreStore"

CoreStoreDemo/CoreStoreDemo/AppDelegate.swift

@@ -8,7 +8,6 @@
 
 import UIKit
 
-import CoreStore
 
 // MARK: - AppDelegate
 

CoreStoreDemo/CoreStoreDemo/Info.plist

@@ -17,11 +17,11 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.0.1</string>
+	<string>4.0.2</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>1</string>
+	<string>4</string>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>UILaunchStoryboardName</key>

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift

@@ -46,7 +46,7 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
         self.present(alert, animated: true, completion: nil)
         
         
-        let modelMetadata = withExtendedLifetime(DataStack(modelName: "MigrationDemo")) {
+        let modelMetadata = withExtendedLifetime(DataStack(xcodeModelName: "MigrationDemo")) {
             (dataStack: DataStack) -> ModelMetadata in
             
             let models = self.models
@@ -91,6 +91,11 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
         }
     }
     
+    func listMonitorDidRefetch(_ monitor: ListMonitor<NSManagedObject>) {
+        
+        self.listMonitorDidChange(monitor)
+    }
+    
     // MARK: UITableViewDataSource
     
     @objc dynamic func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
@@ -148,7 +153,10 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
             label: "Model V1",
             entityType: OrganismV1.self,
             schemaHistory: SchemaHistory(
-                modelName: "MigrationDemo",
+                XcodeDataModelSchema.from(
+                    modelName: "MigrationDemo",
+                    migrationChain: ["MigrationDemoV3", "MigrationDemoV2", "MigrationDemo"]
+                ),
                 migrationChain: ["MigrationDemoV3", "MigrationDemoV2", "MigrationDemo"]
             )
         ),
@@ -156,7 +164,13 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
             label: "Model V2",
             entityType: OrganismV2.self,
             schemaHistory: SchemaHistory(
-                modelName: "MigrationDemo",
+                XcodeDataModelSchema.from(
+                    modelName: "MigrationDemo",
+                    migrationChain: [
+                        "MigrationDemo": "MigrationDemoV2",
+                        "MigrationDemoV3": "MigrationDemoV2"
+                    ]
+                ),
                 migrationChain: [
                     "MigrationDemo": "MigrationDemoV2",
                     "MigrationDemoV3": "MigrationDemoV2"
@@ -167,7 +181,10 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
             label: "Model V3",
             entityType: OrganismV3.self,
             schemaHistory: SchemaHistory(
-                modelName: "MigrationDemo",
+                XcodeDataModelSchema.from(
+                    modelName: "MigrationDemo",
+                    migrationChain: ["MigrationDemo", "MigrationDemoV2", "MigrationDemoV3"]
+                ),
                 migrationChain: ["MigrationDemo", "MigrationDemoV2", "MigrationDemoV3"]
             )
         )

CoreStoreDemo/CoreStoreDemo/Stack Setup Demo/StackSetupDemoViewController.swift

@@ -17,7 +17,7 @@ private struct Static {
     
     static let facebookStack: DataStack = {
         
-        let dataStack = DataStack(modelName: "StackSetupDemo")
+        let dataStack = DataStack(xcodeModelName: "StackSetupDemo")
         try! dataStack.addStorageAndWait(
             SQLiteStore(
                 fileName: "AccountsDemo_FB_Male.sqlite",
@@ -55,7 +55,7 @@ private struct Static {
     
     static let twitterStack: DataStack = {
         
-        let dataStack = DataStack(modelName: "StackSetupDemo")
+        let dataStack = DataStack(xcodeModelName: "StackSetupDemo")
         try! dataStack.addStorageAndWait(
             SQLiteStore(
                 fileName: "AccountsDemo_TW_Male.sqlite",

README.md

@@ -22,6 +22,8 @@ Unleashing the real power of Core Data with the elegance and safety of Swift
 
 Upgrading from CoreStore 3.x to 4.x? Check out the [new features](#features) and make sure to read the [Migration guide](#upgrading-from-3xx-to-4xx).
 
+CoreStore is now part of the [Swift Source Compatibility projects](https://swift.org/source-compatibility/#current-list-of-projects).
+
 
 ## Why use CoreStore?
 CoreStore is the answer to the [challenges](http://inessential.com/2010/02/26/on_switching_away_from_core_data) [of](http://bsktapp.com/blog/why-is-realm-great-and-why-are-we-not-using-it/) [using](https://www.quora.com/Why-would-you-use-Realm-over-Core-Data) [Core](http://sebastiandobrincu.com/blog/5-reasons-why-you-should-choose-realm-over-coredata) [Data](https://medium.com/the-way-north/ditching-core-data-865c1bb5564c#.a5h8ou6ri). 
@@ -88,6 +90,7 @@ CoreStore was (and is) heavily shaped by real-world needs of developing data-dep
         - [Observe a list of objects](#observe-a-list-of-objects)
     - [Objective-C support](#objective-c-support)
     - [Type-safe `CoreStoreObject`s](#type-safe-corestoreobjects)
+        - [`VersionLock`s](#versionlocks)
 - [Roadmap](#roadmap)
 - [Installation](#installation)
 - [Changesets](#changesets)
@@ -1696,6 +1699,39 @@ let puppies = CoreStore.fetchAll(
 
 All CoreStore APIs that are usable with `NSManagedObject`s are also available for `CoreStoreObject`s. These include `ListMonitor`s, `ImportableObject`s, fetching, etc.
 
+### `VersionLock`s
+
+While it is convenient to be able to declare entities only in code, it is worrying that we might accidentally change the `CoreStoreObject`'s properties and break our users' model version history. For this, the `CoreStoreSchema` allows us to "lock" our properties to a particular configuration. Any changes to that `VersionLock` will raise an assertion failure during the `CoreStoreSchema` initialization, so you can then look for the commit which changed the `VersionLock` hash.
+
+To use `VersionLock`s, create the `CoreStoreSchema`, run the app, and look for this particular log message that is automatically printed to the console:
+
+<img width="700" alt="VersionLock" src="https://cloud.githubusercontent.com/assets/3029684/26525632/757f1bd0-4398-11e7-9795-4132a2df0538.png" />
+
+Copy this dictionary value and use it as the `versionLock:` argument of the `CoreStoreSchema` initializer:
+```swift
+CoreStoreSchema(
+    modelVersion: "V1",
+    entities: [
+        Entity<Animal>("Animal", isAbstract: true),
+        Entity<Dog>("Dog"),
+        Entity<Person>("Person"),
+    ],
+    versionLock: [
+        "Animal": [0x1b59d511019695cf, 0xdeb97e86c5eff179, 0x1cfd80745646cb3, 0x4ff99416175b5b9a],
+        "Dog": [0xe3f0afeb109b283a, 0x29998d292938eb61, 0x6aab788333cfc2a3, 0x492ff1d295910ea7],
+        "Person": [0x66d8bbfd8b21561f, 0xcecec69ecae3570f, 0xc4b73d71256214ef, 0x89b99bfe3e013e8b]
+    ]
+)
+```
+You can also get this hash after the `DataStack` has been fully set up by printing to the console:
+```swift
+print(CoreStore.defaultStack.modelSchema.printCoreStoreSchema())
+```
+
+Once the version lock is set, any changes in the properties or to the model will trigger an assertion failure similar to this:
+
+<img width="700" alt="VersionLock failure" src="https://cloud.githubusercontent.com/assets/3029684/26525666/92f46f0c-4399-11e7-9395-4379f6f20876.png" />
+
 
 # Installation
 - Requires:

Sources/CustomSchemaMappingProvider.swift

@@ -32,7 +32,7 @@ import Foundation
 /**
  A `SchemaMappingProvider` that accepts custom mappings for some entities. Mappings of entities with no `CustomMapping` provided will be automatically calculated if possible.
  */
-open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
+public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
     
     /**
      The source model version for the mapping.

Sources/DynamicSchema+Convenience.swift

@@ -32,7 +32,7 @@ import Foundation
 public extension DynamicSchema {
     
     /**
-     Prints the `DynamicSchema` as their corresponding `CoreStoreObject` Swift declarations. This is useful for converting current `XcodeDataModelSchema`-based models into the new `CoreStoreSchema` framework. Additional adjustments may need to be done to the generated source code for "Transformable" attributes.
+     Prints the `DynamicSchema` as their corresponding `CoreStoreObject` Swift declarations. This is useful for converting current `XcodeDataModelSchema`-based models into the new `CoreStoreSchema` framework. Additional adjustments may need to be done to the generated source code; for example: `Transformable` concrete types need to be provided, as well as `default` values.
      
      - Important: After transitioning to the new `CoreStoreSchema` framework, it is recommended to add the new schema as a new version that the existing versions' `XcodeDataModelSchema` can migrate to. It is discouraged to load existing SQLite files created with `XcodeDataModelSchema` directly into a `CoreStoreSchema`.
      - returns: a string that represents the source code for the `DynamicSchema` as their corresponding `CoreStoreObject` Swift declarations.
@@ -153,8 +153,7 @@ public extension DynamicSchema {
                         }
                     case .dateAttributeType:
                         valueType = Date.self
-                        if let defaultValue = (attribute.defaultValue as! Date.ImportableNativeType?).flatMap(Date.cs_fromImportableNativeType),
+                        if let defaultValue = (attribute.defaultValue as! Date.ImportableNativeType?).flatMap(Date.cs_fromImportableNativeType) {
-                            defaultValue != Date.cs_emptyValue() {
                             
                             defaultString = ", default: Date(timeIntervalSinceReferenceDate: \(defaultValue.timeIntervalSinceReferenceDate))"
                         }
@@ -194,9 +193,11 @@ public extension DynamicSchema {
                     let indexedString = attribute.isIndexed ? ", isIndexed: true" : ""
                     let transientString = attribute.isTransient ? ", isTransient: true" : ""
                     // TODO: escape strings
-                    let versionHashModifierString = attribute.versionHashModifier.flatMap({ ", versionHashModifier: \"\($0)\"" }) ?? ""
+                    let versionHashModifierString = attribute.versionHashModifier
+                        .flatMap({ ", versionHashModifier: \"\($0)\"" }) ?? ""
                     // TODO: escape strings
-                    let renamingIdentifierString = attribute.renamingIdentifier.flatMap({ ", renamingIdentifier: \"\($0)\"" }) ?? ""
+                    let renamingIdentifierString = attribute.renamingIdentifier
+                        .flatMap({ ($0 == attributeName ? "" : ", renamingIdentifier: \"\($0)\"") as String }) ?? ""
                     output.append("    let \(attributeName) = \(containerType)<\(String(describing: valueType))>(\"\(attributeName)\"\(indexedString)\(defaultString)\(transientString)\(versionHashModifierString)\(renamingIdentifierString))\n")
                 }
             }
@@ -261,8 +262,10 @@ public extension DynamicSchema {
                             fatalError("Unsupported delete rule \((relationship.deleteRule)) for relationship \"\(relationshipQualifier)\"")
                         }
                     }
-                    let versionHashModifierString = relationship.versionHashModifier.flatMap({ ", versionHashModifier: \"\($0)\"" }) ?? ""
+                    let versionHashModifierString = relationship.versionHashModifier
-                    let renamingIdentifierString = relationship.renamingIdentifier.flatMap({ ", renamingIdentifier: \"\($0)\"" }) ?? ""
+                        .flatMap({ ", versionHashModifier: \"\($0)\"" }) ?? ""
+                    let renamingIdentifierString = relationship.renamingIdentifier
+                        .flatMap({ ($0 == relationshipName ? "" : ", renamingIdentifier: \"\($0)\"") as String }) ?? ""
                     output.append("    let \(relationshipName) = \(containerType)<\(relationship.destinationEntity!.name!)>(\"\(relationshipName)\"\(inverseString)\(deleteRuleString)\(minCountString)\(maxCountString)\(versionHashModifierString)\(renamingIdentifierString))\n")
                 }
             }

Sources/ImportableAttributeType.swift

@@ -64,12 +64,6 @@ public protocol ImportableAttributeType: QueryableAttributeType {
      */
     associatedtype ImportableNativeType: QueryableNativeType
     
-    /**
-     Returns the default "empty" value for this type.
-     */
-    @inline(__always)
-    static func cs_emptyValue() -> Self
-    
     /**
      Creates an instance of this type from its `ImportableNativeType` value.
      */
@@ -84,18 +78,31 @@ public protocol ImportableAttributeType: QueryableAttributeType {
 }
 
 
+// MARK: - EmptyableAttributeType
+
+/**
+ `ImportableAttributeType`s that have a natural "empty" value. Example: `0` for `Int`, `""` for `String`.
+ 
+ - Discussion: Not all `ImportableAttributeType`s can have empty values. `URL`s and `Date`s for example have no obvious empty values.
+ */
+public protocol EmptyableAttributeType: ImportableAttributeType {
+    
+    /**
+     Returns the default "empty" value for this type.
+     */
+    @inline(__always)
+    static func cs_emptyValue() -> Self
+}
+
+
 // MARK: - Bool
 
-extension Bool: ImportableAttributeType {
+extension Bool: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Bool {
-        
-        return false
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Bool? {
         
@@ -107,21 +114,26 @@ extension Bool: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Bool {
+        
+        return false
+    }
 }
 
 
 // MARK: - CGFloat
 
-extension CGFloat: ImportableAttributeType {
+extension CGFloat: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> CGFloat {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> CGFloat? {
         
@@ -133,21 +145,26 @@ extension CGFloat: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> CGFloat {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Data
 
-extension Data: ImportableAttributeType {
+extension Data: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSData
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Data {
-        
-        return Data()
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Data? {
         
@@ -159,6 +176,15 @@ extension Data: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Data {
+        
+        return Data()
+    }
 }
 
 
@@ -166,13 +192,9 @@ extension Data: ImportableAttributeType {
 
 extension Date: ImportableAttributeType {
     
-    public typealias ImportableNativeType = NSDate
+    // MARK: ImportableAttributeType
     
-    @inline(__always)
+    public typealias ImportableNativeType = NSDate
-    public static func cs_emptyValue() -> Date {
-        
-        return Date(timeIntervalSinceReferenceDate: 0)
-    }
     
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Date? {
@@ -190,16 +212,12 @@ extension Date: ImportableAttributeType {
 
 // MARK: - Double
 
-extension Double: ImportableAttributeType {
+extension Double: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Double {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Double? {
         
@@ -211,21 +229,26 @@ extension Double: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Double {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Float
 
-extension Float: ImportableAttributeType {
+extension Float: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Float {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Float? {
         
@@ -237,21 +260,26 @@ extension Float: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Float {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Int
 
-extension Int: ImportableAttributeType {
+extension Int: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Int {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int? {
         
@@ -263,21 +291,26 @@ extension Int: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Int {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Int8
 
-extension Int8: ImportableAttributeType {
+extension Int8: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Int8 {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int8? {
         
@@ -289,21 +322,26 @@ extension Int8: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Int8 {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Int16
 
-extension Int16: ImportableAttributeType {
+extension Int16: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Int16 {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int16? {
         
@@ -315,21 +353,26 @@ extension Int16: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Int16 {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Int32
 
-extension Int32: ImportableAttributeType {
+extension Int32: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Int32 {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int32? {
         
@@ -341,21 +384,26 @@ extension Int32: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Int32 {
+        
+        return 0
+    }
 }
 
 
 // MARK: - Int64
 
-extension Int64: ImportableAttributeType {
+extension Int64: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @inline(__always)
-    public static func cs_emptyValue() -> Int64 {
-        
-        return 0
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int64? {
         
@@ -367,21 +415,26 @@ extension Int64: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> Int64 {
+        
+        return 0
+    }
 }
 
 
 // MARK: - NSData
 
-extension NSData: ImportableAttributeType {
+extension NSData: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSData
     
-    @nonobjc @inline(__always)
-    public class func cs_emptyValue() -> Self {
-        
-        return self.init()
-    }
-    
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
@@ -393,6 +446,15 @@ extension NSData: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @nonobjc @inline(__always)
+    public class func cs_emptyValue() -> Self {
+        
+        return self.init()
+    }
 }
 
 
@@ -400,13 +462,9 @@ extension NSData: ImportableAttributeType {
 
 extension NSDate: ImportableAttributeType {
     
-    public typealias ImportableNativeType = NSDate
+    // MARK: ImportableAttributeType
     
-    @nonobjc @inline(__always)
+    public typealias ImportableNativeType = NSDate
-    public class func cs_emptyValue() -> Self {
-        
-        return self.init(timeIntervalSinceReferenceDate: 0)
-    }
     
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
@@ -424,16 +482,12 @@ extension NSDate: ImportableAttributeType {
 
 // MARK: - NSNumber
 
-extension NSNumber: ImportableAttributeType {
+extension NSNumber: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSNumber
     
-    @nonobjc @inline(__always)
-    public class func cs_emptyValue() -> Self {
-        
-        return self.init()
-    }
-    
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
@@ -445,21 +499,26 @@ extension NSNumber: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @nonobjc @inline(__always)
+    public class func cs_emptyValue() -> Self {
+        
+        return self.init()
+    }
 }
 
 
 // MARK: - NSString
 
-extension NSString: ImportableAttributeType {
+extension NSString: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSString
     
-    @nonobjc @inline(__always)
-    public class func cs_emptyValue() -> Self {
-        
-        return self.init()
-    }
-    
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
@@ -471,6 +530,15 @@ extension NSString: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @nonobjc @inline(__always)
+    public class func cs_emptyValue() -> Self {
+        
+        return self.init()
+    }
 }
 
 
@@ -478,13 +546,9 @@ extension NSString: ImportableAttributeType {
 
 extension NSURL: ImportableAttributeType {
     
-    public typealias ImportableNativeType = NSString
+    // MARK: ImportableAttributeType
     
-    @nonobjc @inline(__always)
+    public typealias ImportableNativeType = NSString
-    public class func cs_emptyValue() -> Self {
-        
-        return self.init(string: "")!
-    }
     
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
@@ -504,16 +568,9 @@ extension NSURL: ImportableAttributeType {
 
 extension NSUUID: ImportableAttributeType {
     
-    public typealias ImportableNativeType = NSString
+    // MARK: ImportableAttributeType
     
-    public class func cs_emptyValue() -> Self {
+    public typealias ImportableNativeType = NSString
-        
-        enum Static {
-            
-            static var zero = Array<UInt8>(repeating: 0, count: 16)
-        }
-        return self.init(uuidBytes: &Static.zero)
-    }
     
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
@@ -531,16 +588,12 @@ extension NSUUID: ImportableAttributeType {
 
 // MARK: - String
 
-extension String: ImportableAttributeType {
+extension String: ImportableAttributeType, EmptyableAttributeType {
+    
+    // MARK: ImportableAttributeType
     
     public typealias ImportableNativeType = NSString
     
-    @inline(__always)
-    public static func cs_emptyValue() -> String {
-        
-        return ""
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> String? {
         
@@ -552,6 +605,15 @@ extension String: ImportableAttributeType {
         
         return self.cs_toQueryableNativeType()
     }
+    
+    
+    // MARK: EmptyableAttributeType
+    
+    @inline(__always)
+    public static func cs_emptyValue() -> String {
+        
+        return ""
+    }
 }
 
 
@@ -559,16 +621,9 @@ extension String: ImportableAttributeType {
 
 extension URL: ImportableAttributeType {
     
-    public typealias ImportableNativeType = NSString
+    // MARK: ImportableAttributeType
     
-    public static func cs_emptyValue() -> URL {
+    public typealias ImportableNativeType = NSString
-        
-        enum Static {
-            
-            static let empty = URL(string: "")!
-        }
-        return Static.empty
-    }
     
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> URL? {
@@ -588,20 +643,9 @@ extension URL: ImportableAttributeType {
 
 extension UUID: ImportableAttributeType {
     
-    public typealias ImportableNativeType = NSString
+    // MARK: ImportableAttributeType
     
-    public static func cs_emptyValue() -> UUID {
+    public typealias ImportableNativeType = NSString
-        
-        enum Static {
-            
-            static let empty: UUID = cs_lazy {
-                
-                var zero = Array<UInt8>(repeating: 0, count: 16)
-                return NSUUID(uuidBytes: &zero) as UUID
-            }
-        }
-        return Static.empty
-    }
     
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> UUID? {
@@ -623,11 +667,6 @@ extension RawRepresentable where RawValue: ImportableAttributeType {
     
     public typealias ImportableNativeType = RawValue.ImportableNativeType
     
-    public static func cs_emptyValue() -> Self {
-        
-        return self.init(rawValue: RawValue.cs_emptyValue())!
-    }
-    
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         

Sources/InferredSchemaMappingProvider.swift

@@ -32,7 +32,7 @@ import Foundation
 /**
  A `SchemaMappingProvider` that tries to infer model migration between two `DynamicSchema` versions by searching all `xcmappingmodel`s from `Bundle.allBundles` or by relying on lightweight migration if possible. Throws an error if lightweight migration is impossible for the two `DynamicSchema`. This mapping is automatically used as a fallback mapping provider, even if no mapping providers are explicitly declared in the `StorageInterface`.
  */
-final class InferredSchemaMappingProvider: Hashable, SchemaMappingProvider {
+public final class InferredSchemaMappingProvider: Hashable, SchemaMappingProvider {
     
     // MARK: Equatable
     

Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>4.0.0</string>
+	<string>4.0.2</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>

Sources/Value.swift

@@ -102,7 +102,7 @@ public enum ValueContainer<O: CoreStoreObject> {
          }
          ```
          - parameter keyPath: the permanent attribute name for this property.
-         - parameter default: the initial value for the property when the object is first created. Defaults to the `ImportableAttributeType`'s empty value if not specified.
+         - parameter default: the initial value for the property when the object is first created. For types that implement `EmptyableAttributeType`s, this argument may be omitted and the type's "empty" value will be used instead (e.g. `false` for `Bool`, `0` for `Int`, `""` for `String`, etc.)
          - parameter isIndexed: `true` if the property should be indexed for searching, otherwise `false`. Defaults to `false` if not specified.
          - parameter isTransient: `true` if the property is transient, otherwise `false`. Defaults to `false` if not specified. The transient flag specifies whether or not a property's value is ignored when an object is saved to a persistent store. Transient properties are not saved to the persistent store, but are still managed for undo, redo, validation, and so on.
          - parameter versionHashModifier: used to mark or denote a property as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
@@ -115,7 +115,7 @@ public enum ValueContainer<O: CoreStoreObject> {
          - parameter finalNewValue: the transformed new value
          - parameter originalNewValue: the original new value
          */
-        public init(_ keyPath: KeyPath, `default`: V = V.cs_emptyValue(), isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V) -> V = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void = { $1($2) }) {
+        public init(_ keyPath: KeyPath, `default`: V, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V) -> V = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void = { $1($2) }) {
             
             self.keyPath = keyPath
             self.isIndexed = isIndexed
@@ -338,6 +338,43 @@ public enum ValueContainer<O: CoreStoreObject> {
     }
 }
 
+public extension ValueContainer.Required where V: EmptyableAttributeType {
+    
+    /**
+     Initializes the metadata for the property. This convenience initializer uses the `EmptyableAttributeType`'s "empty" value as the initial value for the property when the object is first created (e.g. `false` for `Bool`, `0` for `Int`, `""` for `String`, etc.)
+     ```
+     class Person: CoreStoreObject {
+         let title = Value.Required<String>("title") // initial value defaults to empty string
+     }
+     ```
+     - parameter keyPath: the permanent attribute name for this property.
+     - parameter isIndexed: `true` if the property should be indexed for searching, otherwise `false`. Defaults to `false` if not specified.
+     - parameter isTransient: `true` if the property is transient, otherwise `false`. Defaults to `false` if not specified. The transient flag specifies whether or not a property's value is ignored when an object is saved to a persistent store. Transient properties are not saved to the persistent store, but are still managed for undo, redo, validation, and so on.
+     - parameter versionHashModifier: used to mark or denote a property as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
+     - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+     - parameter customGetter: use this closure to make final transformations to the property's value before returning from the getter.
+     - parameter self: the `CoreStoreObject`
+     - parameter getValue: the original getter for the property
+     - parameter customSetter: use this closure to make final transformations to the new value before assigning to the property.
+     - parameter setValue: the original setter for the property
+     - parameter finalNewValue: the transformed new value
+     - parameter originalNewValue: the original new value
+     */
+    public convenience init(_ keyPath: KeyPath, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V) -> V = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void = { $1($2) }) {
+        
+        self.init(
+            keyPath,
+            default: V.cs_emptyValue(),
+            isIndexed: isIndexed,
+            isTransient: isTransient,
+            versionHashModifier: versionHashModifier,
+            renamingIdentifier: renamingIdentifier,
+            customGetter: customGetter,
+            customSetter: customSetter
+        )
+    }
+}
+
 
 // MARK: - TransformableContainer
 

Sources/XcodeSchemaMappingProvider.swift

@@ -32,7 +32,7 @@ import Foundation
 /**
  A `SchemaMappingProvider` that tries to infer model migration between two `DynamicSchema` versions by loading an xcmappingmodel file from the specified `Bundle`. Throws `CoreStoreError.mappingModelNotFound` if the xcmappingmodel file cannot be found, or if the xcmappingmodel doesn't resolve the source and destination `DynamicSchema`.
  */
-final class XcodeSchemaMappingProvider: Hashable, SchemaMappingProvider {
+public final class XcodeSchemaMappingProvider: Hashable, SchemaMappingProvider {
     
     /**
      The source model version for the mapping.