updated error handling for DataStack methods, updated migration demo app

CoreStore.xcodeproj/project.pbxproj

@@ -64,6 +64,7 @@
 		B5E84F411AFF8CCD0064E85B /* ClauseTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5E84F401AFF8CCD0064E85B /* ClauseTypes.swift */; };
 		B5FAD6A91B50A4B400714891 /* NSProgress+Convenience.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5FAD6A81B50A4B300714891 /* NSProgress+Convenience.swift */; };
 		B5FAD6AC1B51285300714891 /* MigrationManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5FAD6AB1B51285300714891 /* MigrationManager.swift */; };
+		B5FAD6AE1B518DCB00714891 /* CoreStore+Migration.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5FAD6AD1B518DCB00714891 /* CoreStore+Migration.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -162,6 +163,7 @@
 		B5E84F401AFF8CCD0064E85B /* ClauseTypes.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ClauseTypes.swift; sourceTree = "<group>"; };
 		B5FAD6A81B50A4B300714891 /* NSProgress+Convenience.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSProgress+Convenience.swift"; sourceTree = "<group>"; };
 		B5FAD6AB1B51285300714891 /* MigrationManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MigrationManager.swift; sourceTree = "<group>"; };
+		B5FAD6AD1B518DCB00714891 /* CoreStore+Migration.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "CoreStore+Migration.swift"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -270,6 +272,7 @@
 			isa = PBXGroup;
 			children = (
 				B56964D31B22FFAD0075EE4A /* DataStack+Migration.swift */,
+				B5FAD6AD1B518DCB00714891 /* CoreStore+Migration.swift */,
 				B56007151B4018AB00A9A8F9 /* MigrationChain.swift */,
 				B56965231B356B820075EE4A /* MigrationResult.swift */,
 			);
@@ -553,6 +556,7 @@
 				B5E84F0E1AFF847B0064E85B /* Tweak.swift in Sources */,
 				B5E84F121AFF847B0064E85B /* OrderBy.swift in Sources */,
 				B5E84F361AFF85470064E85B /* NSManagedObjectContext+Setup.swift in Sources */,
+				B5FAD6AE1B518DCB00714891 /* CoreStore+Migration.swift in Sources */,
 				B5E84EE71AFF84610064E85B /* CoreStore+Logging.swift in Sources */,
 				B56007111B3F6BD500A9A8F9 /* Into.swift in Sources */,
 				B5E84F111AFF847B0064E85B /* Select.swift in Sources */,

CoreStore/Convenience Helpers/NSProgress+Convenience.swift

@@ -50,9 +50,8 @@ public extension NSProgress {
         
         get {
             
-            let object: AnyObject? = getAssociatedObjectForKey(&PropertyKeys.progressObserver, inObject: self)
+            let object: ProgressObserver? = getAssociatedObjectForKey(&PropertyKeys.progressObserver, inObject: self)
-                
+            if let observer = object {
-            if let observer = object as? ProgressObserver {
                 
                 return observer
             }
@@ -72,41 +71,58 @@ public extension NSProgress {
 
 @objc private final class ProgressObserver: NSObject {
     
-    private weak var progress: NSProgress?
+    private unowned let progress: NSProgress
-    private var progressHandler: ((progress: NSProgress) -> Void)?
+    private var progressHandler: ((progress: NSProgress) -> Void)? {
+        
+        didSet {
+            
+            let progressHandler = self.progressHandler
+            if (progressHandler == nil) == (oldValue == nil) {
+                
+                return
+            }
+            
+            if let _ = progressHandler {
+                
+                self.progress.addObserver(
+                    self,
+                    forKeyPath: "fractionCompleted",
+                    options: [.Initial, .New],
+                    context: nil
+                )
+            }
+            else {
+                
+                self.progress.removeObserver(self, forKeyPath: "fractionCompleted")
+            }
+        }
+    }
     
     private init(_ progress: NSProgress) {
         
         self.progress = progress
         super.init()
-        
-        progress.addObserver(
-            self,
-            forKeyPath: "fractionCompleted",
-            options: .New,
-            context: nil
-        )
     }
     
     deinit {
         
-        progress?.removeObserver(self, forKeyPath: "fractionCompleted")
+        if let _ = self.progressHandler {
+            
+            self.progressHandler = nil
+            self.progress.removeObserver(self, forKeyPath: "fractionCompleted")
+        }
     }
     
     override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
         
-        guard let progress = self.progress where object as? NSProgress == progress && keyPath == "fractionCompleted" else {
+        guard let progress = object as? NSProgress where progress == self.progress && keyPath == "fractionCompleted" else {
             
-            super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
             return
         }
         
         GCDQueue.Main.async { [weak self] () -> Void in
             
-            if let strongSelf = self, let progress = strongSelf.progress {
+            self?.progressHandler?(progress: progress)
-                
-                strongSelf.progressHandler?(progress: progress)
-            }
         }
     }
 }

CoreStore/Internal/NSManagedObjectModel+Setup.swift

@@ -52,7 +52,6 @@ internal extension NSManagedObjectModel {
         
         let modelVersions = Set(versionHashes.keys)
         let currentModelVersion: String
-        
         if let modelVersion = modelVersion {
             
             currentModelVersion = modelVersion

CoreStore/Migrating/CoreStore+Migration.swift

@@ -0,0 +1,144 @@
+//
+//  CoreStore+Migration.swift
+//  CoreStore
+//
+//  Copyright (c) 2015 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import Foundation
+import CoreData
+import GCDKit
+
+
+// MARK: - CoreStore
+
+public extension CoreStore {
+    
+    /**
+    Asynchronously adds to the `defaultStack` an SQLite store from the given SQLite file name. Note that using `addSQLiteStore(...)` instead of `addSQLiteStoreAndWait(...)` implies that the migrations are allowed and expected (thus the asynchronous `completion`.)
+    
+    - parameter fileName: the local filename for the SQLite persistent store in the "Application Support" directory. A new SQLite file will be created if it does not exist. Note that if you have multiple configurations, you will need to specify a different `fileName` explicitly for each of them.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`, the "Default" configuration. Note that if you have multiple configurations, you will need to specify a different `fileName` explicitly for each of them.
+    - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.allBundles()`.
+    - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `PersistentStoreResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a `.Failure` result if an error occurs asynchronously.
+    - returns: an `NSProgress` instance if a migration has started, or `nil` is no migrations are required
+    */
+    public static func addSQLiteStore(fileName fileName: String, configuration: String? = nil, mappingModelBundles: [NSBundle]? = nil, completion: (PersistentStoreResult) -> Void) throws -> NSProgress? {
+        
+        return try self.defaultStack.addSQLiteStore(
+            fileName: fileName,
+            configuration: configuration,
+            mappingModelBundles: mappingModelBundles,
+            completion: completion
+        )
+    }
+    
+    /**
+    Asynchronously adds to the `defaultStack` an SQLite store from the given SQLite file URL. Note that using `addSQLiteStore(...)` instead of `addSQLiteStoreAndWait(...)` implies that the migrations are allowed and expected (thus the asynchronous `completion`.)
+    
+    - parameter fileURL: the local file URL for the SQLite persistent store. A new SQLite file will be created if it does not exist. If not specified, defaults to a file URL pointing to a "<Application name>.sqlite" file in the "Application Support" directory. Note that if you have multiple configurations, you will need to specify a different `fileURL` explicitly for each of them.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`, the "Default" configuration. Note that if you have multiple configurations, you will need to specify a different `fileURL` explicitly for each of them.
+    - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.allBundles()`.
+    - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `PersistentStoreResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a `.Failure` result if an error occurs asynchronously.
+    - returns: an `NSProgress` instance if a migration has started, or `nil` is no migrations are required
+    */
+    public static func addSQLiteStore(fileURL fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, mappingModelBundles: [NSBundle]? = NSBundle.allBundles(), completion: (PersistentStoreResult) -> Void) throws -> NSProgress? {
+        
+        return try self.defaultStack.addSQLiteStore(
+            fileURL: fileURL,
+            configuration: configuration,
+            mappingModelBundles: mappingModelBundles,
+            completion: completion
+        )
+    }
+    
+    /**
+    Using the `defaultStack`, migrates an SQLite store with the specified filename to the `DataStack`'s managed object model version WITHOUT adding the migrated store to the data stack.
+    
+    - parameter fileName: the local filename for the SQLite persistent store in the "Application Support" directory.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil` which indicates the "Default" configuration.
+    - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.mainBundle()`.
+    - parameter sourceBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.mainBundle()`.
+    - returns: an `NSProgress` instance if a migration has started, or `nil` is no migrations are required
+    */
+    public static func upgradeSQLiteStoreIfNeeded(fileName fileName: String, configuration: String? = nil, mappingModelBundles: [NSBundle]? = nil, completion: (MigrationResult) -> Void) throws -> NSProgress? {
+        
+        return try self.defaultStack.upgradeSQLiteStoreIfNeeded(
+            fileName: fileName,
+            configuration: configuration,
+            mappingModelBundles: mappingModelBundles,
+            completion: completion
+        )
+    }
+    
+    /**
+    Using the `defaultStack`, migrates an SQLite store at the specified file URL and configuration name to the `DataStack`'s managed object model version. This method does NOT add the migrated store to the data stack.
+    
+    - parameter fileName: the local filename for the SQLite persistent store in the "Application Support" directory.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil` which indicates the "Default" configuration.
+    - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.mainBundle()`.
+    - parameter sourceBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.mainBundle()`.
+    - returns: an `NSProgress` instance if a migration has started, or `nil` is no migrations are required
+    */
+    public static func upgradeSQLiteStoreIfNeeded(fileURL fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, mappingModelBundles: [NSBundle]? = nil, completion: (MigrationResult) -> Void) throws -> NSProgress? {
+        
+        return try self.defaultStack.upgradeSQLiteStoreIfNeeded(
+            fileURL: fileURL,
+            configuration: configuration,
+            mappingModelBundles: mappingModelBundles,
+            completion: completion
+        )
+    }
+    
+    /**
+    Using the `defaultStack`, checks for the required migrations needed for the store with the specified filename and configuration to be migrated to the `DataStack`'s managed object model version. This method throws an error if the store does not exist, if inspection of the store failed, or no mapping model was found/inferred.
+    
+    - parameter fileName: the local filename for the SQLite persistent store in the "Application Support" directory.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil` which indicates the "Default" configuration.
+    - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.allBundles()`.
+    :return: an array of `MigrationType`s indicating the chain of migrations required for the store; or `nil` if either inspection of the store failed, or no mapping model was found/inferred. `MigrationType` acts as a `Bool` and evaluates to `false` if no migration is required, and `true` if either a lightweight or custom migration is needed.
+    */
+    public static func requiredMigrationsForSQLiteStore(fileName fileName: String, configuration: String? = nil, mappingModelBundles: [NSBundle] = NSBundle.allBundles() as [NSBundle]) throws -> [MigrationType] {
+        
+        return try self.defaultStack.requiredMigrationsForSQLiteStore(
+            fileName: fileName,
+            configuration: configuration,
+            mappingModelBundles: mappingModelBundles
+        )
+    }
+    
+    /**
+    Using the `defaultStack`, checks if the store at the specified file URL and configuration needs to be migrated to the `DataStack`'s managed object model version.
+    
+    - parameter fileURL: the local file URL for the SQLite persistent store.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil` which indicates the "Default" configuration.
+    - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.allBundles()`.
+    :return: a `MigrationType` indicating the type of migration required for the store; or `nil` if either inspection of the store failed, or no mapping model was found/inferred. `MigrationType` acts as a `Bool` and evaluates to `false` if no migration is required, and `true` if either a lightweight or custom migration is needed.
+    */
+    public static func requiredMigrationsForSQLiteStore(fileURL fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, mappingModelBundles: [NSBundle] = NSBundle.allBundles() as [NSBundle]) throws -> [MigrationType] {
+        
+        return try self.defaultStack.requiredMigrationsForSQLiteStore(
+            fileURL: fileURL,
+            configuration: configuration,
+            mappingModelBundles: mappingModelBundles
+        )
+    }
+}

CoreStore/Migrating/DataStack+Migration.swift

@@ -38,7 +38,7 @@ public extension DataStack {
     - parameter fileName: the local filename for the SQLite persistent store in the "Application Support" directory. A new SQLite file will be created if it does not exist. Note that if you have multiple configurations, you will need to specify a different `fileName` explicitly for each of them.
     - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`, the "Default" configuration. Note that if you have multiple configurations, you will need to specify a different `fileName` explicitly for each of them.
     - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.allBundles()`.
-    - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `PersistentStoreResult` argument indicates the result. If an error is thrown, this closure will not be executed.
+    - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `PersistentStoreResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a `.Failure` result if an error occurs asynchronously.
     - returns: an `NSProgress` instance if a migration has started, or `nil` is no migrations are required
     */
     public func addSQLiteStore(fileName fileName: String, configuration: String? = nil, mappingModelBundles: [NSBundle]? = nil, completion: (PersistentStoreResult) -> Void) throws -> NSProgress? {
@@ -60,7 +60,7 @@ public extension DataStack {
     - parameter fileURL: the local file URL for the SQLite persistent store. A new SQLite file will be created if it does not exist. If not specified, defaults to a file URL pointing to a "<Application name>.sqlite" file in the "Application Support" directory. Note that if you have multiple configurations, you will need to specify a different `fileURL` explicitly for each of them.
     - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`, the "Default" configuration. Note that if you have multiple configurations, you will need to specify a different `fileURL` explicitly for each of them.
     - parameter mappingModelBundles: an optional array of bundles to search mapping model files from. If not set, defaults to the `NSBundle.allBundles()`.
-    - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `PersistentStoreResult` argument indicates the result.
+    - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `PersistentStoreResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a `.Failure` result if an error occurs asynchronously.
     - returns: an `NSProgress` instance if a migration has started, or `nil` is no migrations are required
     */
     public func addSQLiteStore(fileURL fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, mappingModelBundles: [NSBundle]? = NSBundle.allBundles(), completion: (PersistentStoreResult) -> Void) throws -> NSProgress? {
@@ -124,28 +124,38 @@ public extension DataStack {
                         return
                     }
                     
-                    let persistentStoreResult = self.addSQLiteStoreAndWait(
+                    do {
-                        fileURL: fileURL,
+                        
-                        configuration: configuration,
+                        let store = try self.addSQLiteStoreAndWait(
-                        automigrating: false,
+                            fileURL: fileURL,
-                        resetStoreOnMigrationFailure: false
+                            configuration: configuration,
-                    )
+                            automigrating: false,
-                    
+                            resetStoreOnMigrationFailure: false
-                    completion(persistentStoreResult)
+                        )
+                        
+                        completion(PersistentStoreResult(store))
+                    }
+                    catch {
+                        
+                        completion(PersistentStoreResult(error as NSError))
+                    }
                 }
             )
         }
         catch let error as NSError
             where error.code == NSFileReadNoSuchFileError && error.domain == NSCocoaErrorDomain {
                 
-                let persistentStoreResult = self.addSQLiteStoreAndWait(
+                let store = try self.addSQLiteStoreAndWait(
                     fileURL: fileURL,
                     configuration: configuration,
                     automigrating: false,
                     resetStoreOnMigrationFailure: false
                 )
                 
-                completion(persistentStoreResult)
+                GCDQueue.Main.async {
+                    
+                    completion(PersistentStoreResult(store))
+                }
                 return nil
         }
         catch {
@@ -312,12 +322,16 @@ public extension DataStack {
         var operations = [NSOperation]()
         var cancelled = false
         
-        let progress = NSProgress(totalUnitCount: numberOfMigrations)
+        let progress = NSProgress(parent: nil, userInfo: nil)
+        progress.totalUnitCount = numberOfMigrations
         
+        // todo nsprogress crashing sometimes
         for (sourceModel, destinationModel, mappingModel, _) in migrationSteps {
             
             progress.becomeCurrentWithPendingUnitCount(1)
-            let childProgress = NSProgress(totalUnitCount: 100)
+            
+            let childProgress = NSProgress(parent: progress, userInfo: nil)
+            childProgress.totalUnitCount = 100
             
             operations.append(
                 NSBlockOperation { [weak self] in
@@ -338,7 +352,6 @@ public extension DataStack {
                                 mappingModel: mappingModel,
                                 progress: childProgress
                             )
-                            childProgress.setProgressHandler(nil)
                         }
                         catch {
                             
@@ -365,9 +378,8 @@ public extension DataStack {
             
             GCDQueue.Main.async {
                 
+                progress.setProgressHandler(nil)
                 completion(migrationResult ?? MigrationResult(migrationTypes))
-                
-                withExtendedLifetime(progress) { (_: NSProgress) -> Void in }
                 return
             }
         }

CoreStore/Setting Up/CoreStore+Setup.swift

@@ -35,12 +35,12 @@ public extension CoreStore {
     /**
     Adds an in-memory store to the `defaultStack`.
     
-    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to nil.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`.
-    - returns: a `PersistentStoreResult` indicating success or failure.
+    - returns: the `NSPersistentStore` added to the stack.
     */
-    public static func addInMemoryStore(configuration: String? = nil) -> PersistentStoreResult {
+    public static func addInMemoryStore(configuration configuration: String? = nil) throws -> NSPersistentStore {
         
-        return self.defaultStack.addInMemoryStore(configuration: configuration)
+        return try self.defaultStack.addInMemoryStore(configuration: configuration)
     }
     
     /**
@@ -50,11 +50,11 @@ public extension CoreStore {
     - parameter configuration: an optional configuration name from the model file. If not specified, defaults to nil.
     - parameter automigrating: Set to true to configure Core Data auto-migration, or false to disable. If not specified, defaults to true.
     - parameter resetStoreOnMigrationFailure: Set to true to delete the store on migration failure; or set to false to throw exceptions on failure instead. Typically should only be set to true when debugging, or if the persistent store can be recreated easily. If not specified, defaults to false
-    - returns: a `PersistentStoreResult` indicating success or failure.
+    - returns: the `NSPersistentStore` added to the stack.
     */
-    public static func addSQLiteStoreAndWait(fileName fileName: String, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) -> PersistentStoreResult {
+    public static func addSQLiteStoreAndWait(fileName fileName: String, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) throws -> NSPersistentStore {
         
-        return self.defaultStack.addSQLiteStoreAndWait(
+        return try self.defaultStack.addSQLiteStoreAndWait(
             fileName: fileName,
             configuration: configuration,
             automigrating: automigrating,
@@ -69,16 +69,15 @@ public extension CoreStore {
     - parameter configuration: an optional configuration name from the model file. If not specified, defaults to nil.
     - parameter automigrating: Set to true to configure Core Data auto-migration, or false to disable. If not specified, defaults to true.
     - parameter resetStoreOnMigrationFailure: Set to true to delete the store on migration failure; or set to false to throw exceptions on failure instead. Typically should only be set to true when debugging, or if the persistent store can be recreated easily. If not specified, defaults to false.
-    - returns: a `PersistentStoreResult` indicating success or failure.
+    - returns: the `NSPersistentStore` added to the stack.
     */
-    public static func addSQLiteStoreAndWait(fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) -> PersistentStoreResult {
+    public static func addSQLiteStoreAndWait(fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) throws -> NSPersistentStore {
         
-        return self.defaultStack.addSQLiteStoreAndWait(
+        return try self.defaultStack.addSQLiteStoreAndWait(
             fileURL: fileURL,
             configuration: configuration,
             automigrating: automigrating,
             resetStoreOnMigrationFailure: resetStoreOnMigrationFailure
         )
     }
-    
 }

CoreStore/Setting Up/DataStack.swift

@@ -67,7 +67,6 @@ public final class DataStack {
         self.coordinator = NSPersistentStoreCoordinator(managedObjectModel: model)
         self.rootSavingContext = NSManagedObjectContext.rootSavingContextForCoordinator(self.coordinator)
         self.mainContext = NSManagedObjectContext.mainContextForRootContext(self.rootSavingContext)
-        self.bundle = bundle
         self.model = model
         self.migrationChain = migrationChain
         
@@ -75,7 +74,7 @@ public final class DataStack {
     }
     
     /**
-    Returns the `DataStack`'s model version. The version string is the same as the name of the .xcdatamodeld file.
+    Returns the `DataStack`'s model version. The version string is the same as the name of the version-specific .xcdatamodeld file.
     */
     public var modelVersion: String {
         
@@ -85,10 +84,10 @@ public final class DataStack {
     /**
     Adds an in-memory store to the stack.
     
-    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to nil.
+    - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`.
-    - returns: a `PersistentStoreResult` indicating success or failure.
+    - returns: the `NSPersistentStore` added to the stack.
     */
-    public func addInMemoryStore(configuration configuration: String? = nil) -> PersistentStoreResult {
+    public func addInMemoryStore(configuration configuration: String? = nil) throws -> NSPersistentStore {
         
         let coordinator = self.coordinator;
         
@@ -114,25 +113,15 @@ public final class DataStack {
         if let store = store {
             
             self.updateMetadataForPersistentStore(store)
-            return PersistentStoreResult(store)
+            return store
         }
         
-        if let error = storeError {
+        let error = storeError ?? NSError(coreStoreErrorCode: .UnknownError)
-            
+        CoreStore.handleError(
-            CoreStore.handleError(
+            error,
-                error,
+            "Failed to add in-memory \(typeName(NSPersistentStore)) to the stack."
-                "Failed to add in-memory \(typeName(NSPersistentStore))."
+        )
-            )
+        throw error
-            return PersistentStoreResult(error)
-        }
-        else {
-            
-            CoreStore.handleError(
-                NSError(coreStoreErrorCode: .UnknownError),
-                "Failed to add in-memory \(typeName(NSPersistentStore))."
-            )
-            return PersistentStoreResult(.UnknownError)
-        }
     }
     
     /**
@@ -142,11 +131,11 @@ public final class DataStack {
     - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`, the "Default" configuration. Note that if you have multiple configurations, you will need to specify a different `fileName` explicitly for each of them.
     - parameter automigrating: Set to true to configure Core Data auto-migration, or false to disable. If not specified, defaults to true.
     - parameter resetStoreOnMigrationFailure: Set to true to delete the store on migration failure; or set to false to throw exceptions on failure instead. Typically should only be set to true when debugging, or if the persistent store can be recreated easily. If not specified, defaults to false
-    - returns: a `PersistentStoreResult` indicating success or failure.
+    - returns: the `NSPersistentStore` added to the stack.
     */
-    public func addSQLiteStoreAndWait(fileName fileName: String, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) -> PersistentStoreResult {
+    public func addSQLiteStoreAndWait(fileName fileName: String, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) throws -> NSPersistentStore {
         
-        return self.addSQLiteStoreAndWait(
+        return try self.addSQLiteStoreAndWait(
             fileURL: applicationSupportDirectory.URLByAppendingPathComponent(
                 fileName,
                 isDirectory: false
@@ -164,9 +153,9 @@ public final class DataStack {
     - parameter configuration: an optional configuration name from the model file. If not specified, defaults to `nil`, the "Default" configuration. Note that if you have multiple configurations, you will need to specify a different `fileURL` explicitly for each of them.
     - parameter automigrating: Set to true to configure Core Data auto-migration, or false to disable. If not specified, defaults to true.
     - parameter resetStoreOnMigrationFailure: Set to true to delete the store on migration failure; or set to false to throw exceptions on failure instead. Typically should only be set to true when debugging, or if the persistent store can be recreated easily. If not specified, defaults to false.
-    - returns: a `PersistentStoreResult` indicating success or failure.
+    - returns: the `NSPersistentStore` added to the stack.
     */
-    public func addSQLiteStoreAndWait(fileURL fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) -> PersistentStoreResult {
+    public func addSQLiteStoreAndWait(fileURL fileURL: NSURL = defaultSQLiteStoreURL, configuration: String? = nil, automigrating: Bool = true, resetStoreOnMigrationFailure: Bool = false) throws -> NSPersistentStore {
         
         CoreStore.assert(
             fileURL.fileURL,
@@ -182,15 +171,16 @@ public final class DataStack {
                 && isExistingStoreAutomigrating == automigrating
                 && store.configurationName == (configuration ?? Into.defaultConfigurationName) {
                     
-                    return PersistentStoreResult(store)
+                    return store
             }
             
+            let error = NSError(coreStoreErrorCode: .DifferentPersistentStoreExistsAtURL)
             CoreStore.handleError(
-                NSError(coreStoreErrorCode: .DifferentPersistentStoreExistsAtURL),
+                error,
                 "Failed to add SQLite \(typeName(NSPersistentStore)) at \"\(fileURL)\" because a different \(typeName(NSPersistentStore)) at that URL already exists."
             )
             
-            return PersistentStoreResult(.DifferentPersistentStoreExistsAtURL)
+            throw error
         }
         
         let fileManager = NSFileManager.defaultManager()
@@ -230,7 +220,7 @@ public final class DataStack {
         if let store = store {
             
             self.updateMetadataForPersistentStore(store)
-            return PersistentStoreResult(store)
+            return store
         }
         
         if let error = storeError
@@ -285,16 +275,16 @@ public final class DataStack {
                 if let store = store {
                     
                     self.updateMetadataForPersistentStore(store)
-                    return PersistentStoreResult(store)
+                    return store
                 }
         }
         
+        let error = storeError ?? NSError(coreStoreErrorCode: .UnknownError)
         CoreStore.handleError(
-            storeError ?? NSError(coreStoreErrorCode: .UnknownError),
+            error,
             "Failed to add SQLite \(typeName(NSPersistentStore)) at \"\(fileURL)\"."
         )
-        
+        throw error
-        return PersistentStoreResult(.UnknownError)
     }
     
     
@@ -303,7 +293,6 @@ public final class DataStack {
     internal let coordinator: NSPersistentStoreCoordinator
     internal let rootSavingContext: NSManagedObjectContext
     internal let mainContext: NSManagedObjectContext
-    internal let bundle: NSBundle
     internal let model: NSManagedObjectModel
     internal let migrationChain: MigrationChain
     internal let childTransactionQueue: GCDQueue = .createSerial("com.corestore.datastack.childtransactionqueue")

CoreStore/Setting Up/PersistentStoreResult.swift

@@ -30,26 +30,28 @@ import CoreData
 // MARK: - PersistentStoreResult
 
 /**
-The `PersistentStoreResult` indicates the result of initializing the persistent store.
+The `PersistentStoreResult` indicates the result of an asynchronous initialization of a persistent store.
 The `PersistentStoreResult` can be treated as a boolean:
 
-    let result = CoreStore.addSQLiteStoreAndWait()
+    try! CoreStore.addSQLiteStore(completion: { (result: PersistentStoreResult) -> Void in
-    if result {
+        if result {
-    	// succeeded
+            // succeeded
-    }
+        }
-    else {
+        else {
-    	// failed
+            // failed
-    }
+        }
+    })
 
 or as an `enum`, where the resulting associated object can also be inspected:
 
-    let result = CoreStore.addSQLiteStoreAndWait()
+    try! CoreStore.addSQLiteStore(completion: { (result: PersistentStoreResult) -> Void in
-    switch result {
+        switch result {
-    case .Success(let persistentStore):
+        case .Success(let persistentStore):
-        // persistentStore is the related NSPersistentStore instance
+            // persistentStore is the related NSPersistentStore instance
-    case .Failure(let error):
+        case .Failure(let error):
-        // error is the NSError instance for the failure
+            // error is the NSError instance for the failure
-    }
+        }
+    })
 ```
 */
 public enum PersistentStoreResult {

CoreStoreDemo/CoreStoreDemo.xcodeproj/project.pbxproj

@@ -11,7 +11,8 @@
 		B503FAE01AFDC71700F90881 /* ObjectObserverDemoViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B503FADC1AFDC71700F90881 /* ObjectObserverDemoViewController.swift */; };
 		B503FAE11AFDC71700F90881 /* Palette.swift in Sources */ = {isa = PBXBuildFile; fileRef = B503FADD1AFDC71700F90881 /* Palette.swift */; };
 		B503FAE21AFDC71700F90881 /* PaletteTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = B503FADE1AFDC71700F90881 /* PaletteTableViewCell.swift */; };
-		B50D67911B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = B50D67901B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel */; };
+		B5125C121B521B78003A42C7 /* OrganismV2ToV3.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = B5125C111B521B78003A42C7 /* OrganismV2ToV3.xcmappingmodel */; };
+		B5125C141B521BA7003A42C7 /* OrganismV3ToV2.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = B5125C131B521BA7003A42C7 /* OrganismV3ToV2.xcmappingmodel */; };
 		B52977D91B120B80003D50A5 /* ObserversViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B52977D81B120B80003D50A5 /* ObserversViewController.swift */; };
 		B52977DD1B120F3B003D50A5 /* TransactionsDemoViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B52977DC1B120F3B003D50A5 /* TransactionsDemoViewController.swift */; };
 		B52977DF1B120F83003D50A5 /* MapKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B52977DE1B120F83003D50A5 /* MapKit.framework */; };
@@ -38,12 +39,12 @@
 		B583A9211AF5F542001F76AF /* CoreStore.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = B583A91B1AF5F4F4001F76AF /* CoreStore.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		B5D9C9191B20AB1900E64F0E /* GCDKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B5D9C9181B20AB1900E64F0E /* GCDKit.framework */; };
 		B5D9C91A1B20AB1900E64F0E /* GCDKit.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = B5D9C9181B20AB1900E64F0E /* GCDKit.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		B5E599321B5240F50084BD5F /* OrganismTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5E599311B5240F50084BD5F /* OrganismTableViewCell.swift */; };
 		B5EE25851B36E23C0000406B /* OrganismV1.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5EE25841B36E23C0000406B /* OrganismV1.swift */; };
 		B5EE25871B36E2520000406B /* OrganismV2.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5EE25861B36E2520000406B /* OrganismV2.swift */; };
 		B5EE258C1B36E40D0000406B /* MigrationsDemoViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5EE258B1B36E40D0000406B /* MigrationsDemoViewController.swift */; };
 		B5EE259B1B3EA4890000406B /* OrganismV3.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5EE259A1B3EA4890000406B /* OrganismV3.swift */; };
 		B5EE259E1B3EC1B20000406B /* OrganismProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5EE259D1B3EC1B20000406B /* OrganismProtocol.swift */; };
-		B5F45A611B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = B5F45A601B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -97,7 +98,8 @@
 		B503FADC1AFDC71700F90881 /* ObjectObserverDemoViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ObjectObserverDemoViewController.swift; sourceTree = "<group>"; };
 		B503FADD1AFDC71700F90881 /* Palette.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Palette.swift; sourceTree = "<group>"; };
 		B503FADE1AFDC71700F90881 /* PaletteTableViewCell.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PaletteTableViewCell.swift; sourceTree = "<group>"; };
-		B50D67901B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcmappingmodel; name = OrganismV3ToV2.xcmappingmodel; path = "CoreStoreDemo/MIgrations Demo/OrganismV3ToV2.xcmappingmodel"; sourceTree = SOURCE_ROOT; };
+		B5125C111B521B78003A42C7 /* OrganismV2ToV3.xcmappingmodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcmappingmodel; path = OrganismV2ToV3.xcmappingmodel; sourceTree = "<group>"; };
+		B5125C131B521BA7003A42C7 /* OrganismV3ToV2.xcmappingmodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcmappingmodel; path = OrganismV3ToV2.xcmappingmodel; sourceTree = "<group>"; };
 		B52977D81B120B80003D50A5 /* ObserversViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ObserversViewController.swift; sourceTree = "<group>"; };
 		B52977DC1B120F3B003D50A5 /* TransactionsDemoViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TransactionsDemoViewController.swift; sourceTree = "<group>"; };
 		B52977DE1B120F83003D50A5 /* MapKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = MapKit.framework; path = System/Library/Frameworks/MapKit.framework; sourceTree = SDKROOT; };
@@ -124,6 +126,7 @@
 		B56965281B3582D30075EE4A /* MigrationDemo.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = MigrationDemo.xcdatamodel; sourceTree = "<group>"; };
 		B583A9141AF5F4F3001F76AF /* CoreStore.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = CoreStore.xcodeproj; path = ../CoreStore.xcodeproj; sourceTree = "<group>"; };
 		B5D9C9181B20AB1900E64F0E /* GCDKit.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = GCDKit.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		B5E599311B5240F50084BD5F /* OrganismTableViewCell.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = OrganismTableViewCell.swift; path = "CoreStoreDemo/MIgrations Demo/OrganismTableViewCell.swift"; sourceTree = SOURCE_ROOT; };
 		B5EE25801B36E1B00000406B /* MigrationDemoV2.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = MigrationDemoV2.xcdatamodel; sourceTree = "<group>"; };
 		B5EE25841B36E23C0000406B /* OrganismV1.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OrganismV1.swift; sourceTree = "<group>"; };
 		B5EE25861B36E2520000406B /* OrganismV2.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OrganismV2.swift; sourceTree = "<group>"; };
@@ -131,7 +134,6 @@
 		B5EE258B1B36E40D0000406B /* MigrationsDemoViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MigrationsDemoViewController.swift; sourceTree = "<group>"; };
 		B5EE259A1B3EA4890000406B /* OrganismV3.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OrganismV3.swift; sourceTree = "<group>"; };
 		B5EE259D1B3EC1B20000406B /* OrganismProtocol.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OrganismProtocol.swift; sourceTree = "<group>"; };
-		B5F45A601B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcmappingmodel; path = OrganismV2ToV3.xcmappingmodel; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -265,9 +267,10 @@
 				B5EE25861B36E2520000406B /* OrganismV2.swift */,
 				B5EE25841B36E23C0000406B /* OrganismV1.swift */,
 				B5EE258B1B36E40D0000406B /* MigrationsDemoViewController.swift */,
-				B5F45A601B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel */,
+				B5E599311B5240F50084BD5F /* OrganismTableViewCell.swift */,
+				B5125C111B521B78003A42C7 /* OrganismV2ToV3.xcmappingmodel */,
 				B560070E1B3EC90F00A9A8F9 /* OrganismV2ToV3MigrationPolicy.swift */,
-				B50D67901B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel */,
+				B5125C131B521BA7003A42C7 /* OrganismV3ToV2.xcmappingmodel */,
 			);
 			path = "Migrations Demo";
 			sourceTree = "<group>";
@@ -380,6 +383,7 @@
 			files = (
 				B56965181B2E20CC0075EE4A /* TimeZone.swift in Sources */,
 				B56965291B3582D30075EE4A /* MigrationDemo.xcdatamodeld in Sources */,
+				B5E599321B5240F50084BD5F /* OrganismTableViewCell.swift in Sources */,
 				B5EE25851B36E23C0000406B /* OrganismV1.swift in Sources */,
 				B52977DD1B120F3B003D50A5 /* TransactionsDemoViewController.swift in Sources */,
 				B52977E41B121635003D50A5 /* Place.swift in Sources */,
@@ -394,11 +398,10 @@
 				B566E3321B11DF3200F4F0C6 /* UserAccount.swift in Sources */,
 				B54AAD521AF4D26E00848AE0 /* CoreStoreDemo.xcdatamodeld in Sources */,
 				B5EE259B1B3EA4890000406B /* OrganismV3.swift in Sources */,
-				B5F45A611B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel in Sources */,
 				B503FAE11AFDC71700F90881 /* Palette.swift in Sources */,
 				B503FAE21AFDC71700F90881 /* PaletteTableViewCell.swift in Sources */,
-				B50D67911B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel in Sources */,
 				B560070F1B3EC90F00A9A8F9 /* OrganismV2ToV3MigrationPolicy.swift in Sources */,
+				B5125C141B521BA7003A42C7 /* OrganismV3ToV2.xcmappingmodel in Sources */,
 				B503FADF1AFDC71700F90881 /* ListObserverDemoViewController.swift in Sources */,
 				B54AAD4F1AF4D26E00848AE0 /* AppDelegate.swift in Sources */,
 				B56964D71B231AE90075EE4A /* StackSetupDemo.xcdatamodeld in Sources */,
@@ -406,6 +409,7 @@
 				B5EE259E1B3EC1B20000406B /* OrganismProtocol.swift in Sources */,
 				B5EE258C1B36E40D0000406B /* MigrationsDemoViewController.swift in Sources */,
 				B569651C1B30889A0075EE4A /* QueryingResultsViewController.swift in Sources */,
+				B5125C121B521B78003A42C7 /* OrganismV2ToV3.xcmappingmodel in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

CoreStoreDemo/CoreStoreDemo/Base.lproj/Main.storyboard

@@ -22,8 +22,7 @@
             <string>HelveticaNeue-Light</string>
             <string>HelveticaNeue-Light</string>
             <string>HelveticaNeue-Light</string>
-            <string>HelveticaNeue-Light</string>
+            <string>HelveticaNeue-Thin</string>
-            <string>HelveticaNeue-Light</string>
             <string>HelveticaNeue-Light</string>
             <string>HelveticaNeue-Light</string>
             <string>HelveticaNeue-Light</string>
@@ -44,7 +43,8 @@
                     <tableView key="view" clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="44" sectionHeaderHeight="22" sectionFooterHeight="22" id="S3A-lm-AuA">
                         <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
-                        <color key="backgroundColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
+                        <color key="backgroundColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <color key="separatorColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                         <view key="tableHeaderView" contentMode="scaleToFill" id="yud-WH-MPa">
                             <rect key="frame" x="0.0" y="64" width="600" height="150"/>
                             <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
@@ -123,118 +123,151 @@
             <point key="canvasLocation" x="3694" y="650"/>
         </scene>
         <!--Evolution-->
-        <scene sceneID="zQS-zk-2T4">
+        <scene sceneID="iwU-Hv-zNr">
             <objects>
-                <tableViewController id="hJK-5I-1TQ" customClass="MigrationsDemoViewController" customModule="CoreStoreDemo" customModuleProvider="target" sceneMemberID="viewController">
+                <viewController automaticallyAdjustsScrollViewInsets="NO" id="iVv-Vc-nCL" customClass="MigrationsDemoViewController" customModule="CoreStoreDemo" customModuleProvider="target" sceneMemberID="viewController">
-                    <tableView key="view" clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="44" sectionHeaderHeight="22" sectionFooterHeight="22" id="KpQ-h6-kAe">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Un6-jI-efh"/>
+                        <viewControllerLayoutGuide type="bottom" id="t9A-zf-Iew"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="75P-2m-6cr">
                         <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
-                        <color key="backgroundColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <subviews>
-                        <color key="separatorColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                            <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="44" sectionHeaderHeight="22" sectionFooterHeight="22" translatesAutoresizingMaskIntoConstraints="NO" id="WUc-3Y-Quw">
-                        <view key="tableHeaderView" contentMode="scaleToFill" id="5Hd-jr-1nW">
+                                <rect key="frame" x="0.0" y="324" width="600" height="276"/>
-                            <rect key="frame" x="0.0" y="64" width="600" height="259"/>
+                                <color key="backgroundColor" red="0.93725490196078431" green="0.93725490196078431" blue="0.95686274509803926" alpha="1" colorSpace="calibratedRGB"/>
-                            <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                <color key="separatorColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
-                            <subviews>
+                                <prototypes>
-                                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Organism" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="C06-r4-27K">
+                                    <tableViewCell contentMode="scaleToFill" selectionStyle="default" indentationWidth="10" reuseIdentifier="OrganismTableViewCell" id="WVb-th-o8c" customClass="OrganismTableViewCell" customModule="CoreStoreDemo" customModuleProvider="target">
-                                    <rect key="frame" x="20" y="90" width="560" height="26.5"/>
+                                        <rect key="frame" x="0.0" y="22" width="600" height="44"/>
-                                    <fontDescription key="fontDescription" name="HelveticaNeue-Bold" family="Helvetica Neue" pointSize="22"/>
+                                        <autoresizingMask key="autoresizingMask"/>
-                                    <color key="textColor" red="0.92549019610000005" green="0.94117647059999998" blue="0.94509803920000002" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                        <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="WVb-th-o8c" id="JBq-Ml-a9p">
-                                    <nil key="highlightedColor"/>
+                                            <rect key="frame" x="0.0" y="0.0" width="600" height="43.5"/>
-                                </label>
+                                            <autoresizingMask key="autoresizingMask"/>
-                                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="attributes" lineBreakMode="wordWrap" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="fXh-OL-4Qb">
+                                            <subviews>
-                                    <rect key="frame" x="20" y="140" width="560" height="20.5"/>
+                                                <button opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="OQf-Bd-Zze">
-                                    <fontDescription key="fontDescription" name="HelveticaNeue-Light" family="Helvetica Neue" pointSize="17"/>
+                                                    <rect key="frame" x="520" y="8" width="72" height="27.5"/>
-                                    <color key="textColor" red="0.92549019610000005" green="0.94117647059999998" blue="0.94509803920000002" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                                    <fontDescription key="fontDescription" type="boldSystem" pointSize="15"/>
-                                    <nil key="highlightedColor"/>
+                                                    <inset key="contentEdgeInsets" minX="7" minY="0.0" maxX="7" maxY="0.0"/>
-                                </label>
+                                                    <state key="normal" title="mutate!"/>
-                                <segmentedControl opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="top" segmentControlStyle="plain" selectedSegmentIndex="0" translatesAutoresizingMaskIntoConstraints="NO" id="Hwa-fO-fC5">
+                                                    <connections>
-                                    <rect key="frame" x="20" y="20" width="560" height="29"/>
+                                                        <action selector="mutateButtonTouchUpInside:" destination="WVb-th-o8c" eventType="touchUpInside" id="REw-UX-rJ0"/>
-                                    <segments>
+                                                    </connections>
-                                        <segment title="First"/>
+                                                </button>
-                                        <segment title="Second"/>
+                                                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Label" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="VZk-6K-4ut">
-                                        <segment title=""/>
+                                                    <rect key="frame" x="15" y="8" width="495" height="27.5"/>
-                                    </segments>
+                                                    <fontDescription key="fontDescription" name="HelveticaNeue-Thin" family="Helvetica Neue" pointSize="17"/>
-                                    <color key="tintColor" cocoaTouchSystemColor="tableCellGroupedBackgroundColor"/>
+                                                    <color key="textColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
-                                    <connections>
+                                                    <nil key="highlightedColor"/>
-                                        <action selector="segmentedControlValueChanged:" destination="hJK-5I-1TQ" eventType="valueChanged" id="jNH-gx-mOg"/>
+                                                </label>
-                                    </connections>
+                                            </subviews>
-                                </segmentedControl>
+                                            <constraints>
-                                <progressView opaque="NO" contentMode="scaleToFill" verticalHuggingPriority="750" progress="0.5" translatesAutoresizingMaskIntoConstraints="NO" id="H1P-2g-DHX">
+                                                <constraint firstItem="OQf-Bd-Zze" firstAttribute="top" secondItem="JBq-Ml-a9p" secondAttribute="topMargin" id="39z-i5-EeS"/>
-                                    <rect key="frame" x="20" y="68" width="560" height="2"/>
+                                                <constraint firstItem="VZk-6K-4ut" firstAttribute="top" secondItem="JBq-Ml-a9p" secondAttribute="topMargin" id="WO1-gf-MIu"/>
-                                    <color key="progressTintColor" red="1" green="1" blue="1" alpha="1" colorSpace="calibratedRGB"/>
+                                                <constraint firstItem="VZk-6K-4ut" firstAttribute="leading" secondItem="JBq-Ml-a9p" secondAttribute="leadingMargin" constant="7" id="X0N-Il-F26"/>
-                                    <color key="trackTintColor" white="1" alpha="0.20000000000000001" colorSpace="calibratedWhite"/>
+                                                <constraint firstAttribute="bottomMargin" secondItem="OQf-Bd-Zze" secondAttribute="bottom" id="YwC-dw-rGI"/>
-                                </progressView>
+                                                <constraint firstItem="OQf-Bd-Zze" firstAttribute="leading" secondItem="VZk-6K-4ut" secondAttribute="trailing" constant="10" id="mo1-NZ-iPa"/>
-                            </subviews>
+                                                <constraint firstAttribute="bottomMargin" secondItem="VZk-6K-4ut" secondAttribute="bottom" id="ucK-FJ-7v4"/>
-                            <color key="backgroundColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                                <constraint firstItem="OQf-Bd-Zze" firstAttribute="trailing" secondItem="JBq-Ml-a9p" secondAttribute="trailingMargin" id="v3e-PY-3wW"/>
-                            <constraints>
+                                            </constraints>
-                                <constraint firstItem="H1P-2g-DHX" firstAttribute="leading" secondItem="5Hd-jr-1nW" secondAttribute="leading" constant="20" id="2Nf-U0-bTq"/>
+                                        </tableViewCellContentView>
-                                <constraint firstItem="fXh-OL-4Qb" firstAttribute="top" secondItem="C06-r4-27K" secondAttribute="bottom" constant="23.5" id="6d1-A5-Zc5"/>
+                                        <connections>
-                                <constraint firstItem="Hwa-fO-fC5" firstAttribute="leading" secondItem="5Hd-jr-1nW" secondAttribute="leading" constant="20" id="CDZ-qV-3eK"/>
+                                            <outlet property="dnaLabel" destination="VZk-6K-4ut" id="CSU-Ig-qMu"/>
-                                <constraint firstItem="H1P-2g-DHX" firstAttribute="top" secondItem="Hwa-fO-fC5" secondAttribute="bottom" constant="20" id="Dcs-Vv-Xfv"/>
+                                            <outlet property="mutateButton" destination="OQf-Bd-Zze" id="5gd-Jx-tMT"/>
-                                <constraint firstItem="fXh-OL-4Qb" firstAttribute="leading" secondItem="C06-r4-27K" secondAttribute="leading" id="SnQ-Ra-KkU"/>
+                                        </connections>
-                                <constraint firstItem="Hwa-fO-fC5" firstAttribute="top" secondItem="5Hd-jr-1nW" secondAttribute="top" constant="20" id="Zo1-kW-kAw"/>
+                                    </tableViewCell>
-                                <constraint firstItem="C06-r4-27K" firstAttribute="top" secondItem="H1P-2g-DHX" secondAttribute="bottom" constant="20" id="bBW-Bn-oeN"/>
+                                </prototypes>
-                                <constraint firstAttribute="trailing" secondItem="fXh-OL-4Qb" secondAttribute="trailing" constant="20" id="mhR-0c-i0n"/>
+                                <connections>
-                                <constraint firstAttribute="trailing" secondItem="C06-r4-27K" secondAttribute="trailing" constant="20" id="s0c-XG-e70"/>
+                                    <outlet property="dataSource" destination="iVv-Vc-nCL" id="yp2-X4-fhE"/>
-                                <constraint firstAttribute="trailing" secondItem="H1P-2g-DHX" secondAttribute="trailing" constant="20" id="swp-18-f5e"/>
+                                    <outlet property="delegate" destination="iVv-Vc-nCL" id="V5b-s8-XOl"/>
-                                <constraint firstItem="C06-r4-27K" firstAttribute="top" secondItem="Hwa-fO-fC5" secondAttribute="bottom" constant="20" id="tYt-wb-Lk8"/>
+                                </connections>
-                                <constraint firstAttribute="trailing" secondItem="Hwa-fO-fC5" secondAttribute="trailing" constant="20" id="ujX-gH-Wlm"/>
+                            </tableView>
-                                <constraint firstItem="C06-r4-27K" firstAttribute="leading" secondItem="5Hd-jr-1nW" secondAttribute="leading" constant="20" id="yiG-c9-BZg"/>
+                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="XKA-Ub-c2X">
-                            </constraints>
+                                <rect key="frame" x="0.0" y="64" width="600" height="260"/>
-                            <variation key="default">
+                                <subviews>
-                                <mask key="constraints">
+                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="i7U-bW-juB" customClass="UIButton">
-                                    <exclude reference="tYt-wb-Lk8"/>
+                                        <rect key="frame" x="0.0" y="0.0" width="600" height="260"/>
-                                </mask>
+                                        <subviews>
-                            </variation>
+                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Organism" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="zxy-nY-P44">
-                        </view>
+                                                <rect key="frame" x="20" y="90.5" width="560" height="26.5"/>
-                        <prototypes>
+                                                <fontDescription key="fontDescription" name="HelveticaNeue-Bold" family="Helvetica Neue" pointSize="22"/>
-                            <tableViewCell contentMode="scaleToFill" selectionStyle="default" indentationWidth="10" reuseIdentifier="UITableViewCell" textLabel="VMh-dq-EWk" detailTextLabel="HIj-ej-FpM" style="IBUITableViewCellStyleValue1" id="hoX-F9-vzZ">
+                                                <color key="textColor" red="0.92549019610000005" green="0.94117647059999998" blue="0.94509803920000002" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
-                                <rect key="frame" x="0.0" y="345" width="600" height="44"/>
+                                                <nil key="highlightedColor"/>
-                                <autoresizingMask key="autoresizingMask"/>
+                                            </label>
-                                <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="hoX-F9-vzZ" id="9ru-7C-dsE">
+                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="attributes" lineBreakMode="wordWrap" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="6Ac-xl-ldZ">
-                                    <rect key="frame" x="0.0" y="0.0" width="600" height="43.5"/>
+                                                <rect key="frame" x="20" y="131.5" width="560" height="20.5"/>
-                                    <autoresizingMask key="autoresizingMask"/>
+                                                <fontDescription key="fontDescription" name="HelveticaNeue-Light" family="Helvetica Neue" pointSize="17"/>
-                                    <subviews>
+                                                <color key="textColor" red="0.92549019610000005" green="0.94117647059999998" blue="0.94509803920000002" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
-                                        <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" text="Title" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="VMh-dq-EWk">
+                                                <nil key="highlightedColor"/>
-                                            <rect key="frame" x="15" y="13" width="28.5" height="19"/>
+                                            </label>
-                                            <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                            <segmentedControl opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="top" segmentControlStyle="plain" selectedSegmentIndex="0" translatesAutoresizingMaskIntoConstraints="NO" id="rAZ-eJ-sxy">
-                                            <fontDescription key="fontDescription" name="HelveticaNeue-Light" family="Helvetica Neue" pointSize="16"/>
+                                                <rect key="frame" x="20" y="20" width="560" height="29"/>
-                                            <color key="textColor" red="0.17254901959999999" green="0.24313725489999999" blue="0.31372549020000001" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                                <segments>
-                                            <nil key="highlightedColor"/>
+                                                    <segment title="First"/>
-                                        </label>
+                                                    <segment title="Second"/>
-                                        <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" text="" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="HIj-ej-FpM">
+                                                    <segment title=""/>
-                                            <rect key="frame" x="546.5" y="13" width="38.5" height="19"/>
+                                                </segments>
-                                            <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                                <color key="tintColor" red="1" green="1" blue="1" alpha="1" colorSpace="calibratedRGB"/>
-                                            <fontDescription key="fontDescription" name="HelveticaNeue-Light" family="Helvetica Neue" pointSize="16"/>
+                                                <connections>
-                                            <color key="textColor" red="0.5568627451" green="0.5568627451" blue="0.57647058819999997" alpha="1" colorSpace="calibratedRGB"/>
+                                                    <action selector="segmentedControlValueChanged:" destination="iVv-Vc-nCL" eventType="valueChanged" id="RwG-kW-RPg"/>
-                                            <nil key="highlightedColor"/>
+                                                </connections>
-                                        </label>
+                                            </segmentedControl>
-                                    </subviews>
+                                            <progressView opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" verticalHuggingPriority="750" progress="0.5" translatesAutoresizingMaskIntoConstraints="NO" id="869-wx-Odb">
-                                </tableViewCellContentView>
+                                                <rect key="frame" x="20" y="68" width="560" height="2"/>
-                            </tableViewCell>
+                                                <color key="progressTintColor" red="1" green="1" blue="1" alpha="1" colorSpace="calibratedRGB"/>
-                        </prototypes>
+                                                <color key="trackTintColor" white="1" alpha="0.20000000000000001" colorSpace="calibratedWhite"/>
-                        <connections>
+                                            </progressView>
-                            <outlet property="dataSource" destination="hJK-5I-1TQ" id="PBz-yT-Uix"/>
+                                        </subviews>
-                            <outlet property="delegate" destination="hJK-5I-1TQ" id="eZs-Fj-9qK"/>
+                                        <color key="backgroundColor" red="0.20392156859999999" green="0.28627450980000002" blue="0.36862745099999999" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
-                        </connections>
+                                        <constraints>
-                    </tableView>
+                                            <constraint firstItem="zxy-nY-P44" firstAttribute="leading" secondItem="i7U-bW-juB" secondAttribute="leading" constant="20" id="1u1-Tq-hRn"/>
-                    <toolbarItems/>
+                                            <constraint firstItem="6Ac-xl-ldZ" firstAttribute="top" secondItem="zxy-nY-P44" secondAttribute="bottom" constant="14.5" id="39B-9l-O3g"/>
-                    <navigationItem key="navigationItem" title="Evolution" id="KvN-Gf-ETO">
+                                            <constraint firstAttribute="trailing" secondItem="zxy-nY-P44" secondAttribute="trailing" constant="20" id="3d5-Zk-rB1"/>
-                        <barButtonItem key="rightBarButtonItem" title="Mutate!" id="J3K-Fc-5yB">
+                                            <constraint firstAttribute="trailing" secondItem="6Ac-xl-ldZ" secondAttribute="trailing" constant="20" id="EJq-uA-8dQ"/>
-                            <connections>
+                                            <constraint firstItem="rAZ-eJ-sxy" firstAttribute="top" secondItem="i7U-bW-juB" secondAttribute="top" constant="20" id="Ey7-mP-RNA"/>
-                                <action selector="mutateBarButtonTapped:" destination="hJK-5I-1TQ" id="rPl-0R-hKM"/>
+                                            <constraint firstItem="zxy-nY-P44" firstAttribute="top" secondItem="869-wx-Odb" secondAttribute="bottom" constant="20.5" id="GU3-JM-b99"/>
-                            </connections>
+                                            <constraint firstItem="rAZ-eJ-sxy" firstAttribute="leading" secondItem="i7U-bW-juB" secondAttribute="leading" constant="20" id="KKJ-gG-pFL"/>
-                        </barButtonItem>
+                                            <constraint firstAttribute="trailing" secondItem="869-wx-Odb" secondAttribute="trailing" constant="20" id="Lni-gD-7h0"/>
-                    </navigationItem>
+                                            <constraint firstItem="869-wx-Odb" firstAttribute="top" secondItem="rAZ-eJ-sxy" secondAttribute="bottom" constant="20" id="QBz-cP-SVZ"/>
-                    <simulatedToolbarMetrics key="simulatedBottomBarMetrics"/>
+                                            <constraint firstAttribute="trailing" secondItem="rAZ-eJ-sxy" secondAttribute="trailing" constant="20" id="WoD-cr-aj9"/>
+                                            <constraint firstAttribute="height" constant="260" id="XTa-ql-yEW"/>
+                                            <constraint firstItem="6Ac-xl-ldZ" firstAttribute="leading" secondItem="i7U-bW-juB" secondAttribute="leading" constant="20" id="jkv-ow-f0q"/>
+                                            <constraint firstItem="869-wx-Odb" firstAttribute="leading" secondItem="i7U-bW-juB" secondAttribute="leading" constant="20" id="qgE-y5-uh8"/>
+                                        </constraints>
+                                    </view>
+                                </subviews>
+                                <color key="backgroundColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
+                                <constraints>
+                                    <constraint firstAttribute="height" constant="260" id="90R-Mf-iAB"/>
+                                    <constraint firstItem="i7U-bW-juB" firstAttribute="leading" secondItem="XKA-Ub-c2X" secondAttribute="leading" id="e9h-f4-c37"/>
+                                    <constraint firstItem="i7U-bW-juB" firstAttribute="top" secondItem="XKA-Ub-c2X" secondAttribute="top" id="vJV-dl-RLx"/>
+                                    <constraint firstAttribute="trailing" secondItem="i7U-bW-juB" secondAttribute="trailing" id="wYt-hg-yKM"/>
+                                </constraints>
+                            </view>
+                        </subviews>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
+                        <constraints>
+                            <constraint firstAttribute="trailing" secondItem="XKA-Ub-c2X" secondAttribute="trailing" id="U0P-51-KT9"/>
+                            <constraint firstAttribute="trailing" secondItem="WUc-3Y-Quw" secondAttribute="trailing" id="i7I-7B-97K"/>
+                            <constraint firstItem="WUc-3Y-Quw" firstAttribute="leading" secondItem="75P-2m-6cr" secondAttribute="leading" id="i8b-GU-yFg"/>
+                            <constraint firstItem="XKA-Ub-c2X" firstAttribute="top" secondItem="Un6-jI-efh" secondAttribute="bottom" id="lU2-wP-RQb"/>
+                            <constraint firstItem="XKA-Ub-c2X" firstAttribute="leading" secondItem="75P-2m-6cr" secondAttribute="leading" id="oa7-qv-9am"/>
+                            <constraint firstItem="t9A-zf-Iew" firstAttribute="top" secondItem="WUc-3Y-Quw" secondAttribute="bottom" id="tts-uy-w5J"/>
+                            <constraint firstItem="WUc-3Y-Quw" firstAttribute="top" secondItem="XKA-Ub-c2X" secondAttribute="bottom" id="vjy-iN-Xi7"/>
+                        </constraints>
+                    </view>
+                    <navigationItem key="navigationItem" title="Evolution" id="uc7-DN-PYG"/>
                     <connections>
-                        <outlet property="organismLabel" destination="fXh-OL-4Qb" id="shX-fK-haw"/>
+                        <outlet property="headerContainer" destination="i7U-bW-juB" id="hpf-7a-yBd"/>
-                        <outlet property="progressView" destination="H1P-2g-DHX" id="Asy-fE-gXI"/>
+                        <outlet property="organismLabel" destination="6Ac-xl-ldZ" id="pgF-ej-ovy"/>
-                        <outlet property="segmentedControl" destination="Hwa-fO-fC5" id="myL-tO-4ah"/>
+                        <outlet property="progressView" destination="869-wx-Odb" id="um3-UM-uOP"/>
-                        <outlet property="titleLabel" destination="C06-r4-27K" id="zQr-YC-moe"/>
+                        <outlet property="segmentedControl" destination="rAZ-eJ-sxy" id="K3Q-X2-Jrm"/>
+                        <outlet property="tableView" destination="WUc-3Y-Quw" id="3Ki-v0-lTb"/>
+                        <outlet property="titleLabel" destination="zxy-nY-P44" id="9JO-hP-yVp"/>
                     </connections>
-                </tableViewController>
+                </viewController>
-                <placeholder placeholderIdentifier="IBFirstResponder" id="H1w-4k-Tpx" userLabel="First Responder" sceneMemberID="firstResponder"/>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="LzB-gZ-6fG" userLabel="First Responder" sceneMemberID="firstResponder"/>
             </objects>
             <point key="canvasLocation" x="3694" y="4113"/>
         </scene>
@@ -408,7 +441,7 @@
                                             </subviews>
                                         </tableViewCellContentView>
                                         <connections>
-                                            <segue destination="hJK-5I-1TQ" kind="show" id="u2O-8c-DSB"/>
+                                            <segue destination="iVv-Vc-nCL" kind="show" id="HbO-rU-Qfj"/>
                                         </connections>
                                     </tableViewCell>
                                 </cells>

CoreStoreDemo/CoreStoreDemo/Fetching and Querying Demo/FetchingAndQueryingDemoViewController.swift

@@ -15,7 +15,7 @@ private struct Static {
     static let timeZonesStack: DataStack = {
         
         let dataStack = DataStack()
-        dataStack.addSQLiteStoreAndWait(
+        try! dataStack.addSQLiteStoreAndWait(
             fileName: "TimeZoneDemo.sqlite",
             configuration: "FetchingAndQueryingDemo",
             resetStoreOnMigrationFailure: true

CoreStoreDemo/CoreStoreDemo/List and Object Observers Demo/ListObserverDemoViewController.swift

@@ -14,7 +14,7 @@ private struct Static {
     
     static let palettes: ListMonitor<Palette> = {
         
-        CoreStore.addSQLiteStoreAndWait(
+        try! CoreStore.addSQLiteStoreAndWait(
             fileName: "ColorsDemo.sqlite",
             configuration: "ObservingDemo",
             resetStoreOnMigrationFailure: true

CoreStoreDemo/CoreStoreDemo/Loggers Demo/CustomLoggerViewController.swift

@@ -30,7 +30,7 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
         
         super.viewDidLoad()
         
-        self.dataStack.addSQLiteStoreAndWait(fileName: "emptyStore.sqlite")
+        try! self.dataStack.addSQLiteStoreAndWait(fileName: "emptyStore.sqlite")
         CoreStore.logger = self
     }
     
@@ -109,7 +109,7 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
             }
             
         case .Some(1):
-            self.dataStack.addSQLiteStoreAndWait(fileName: "emptyStore.sqlite", configuration: "invalidStore")
+            try! self.dataStack.addSQLiteStoreAndWait(fileName: "emptyStore.sqlite", configuration: "invalidStore")
             
         case .Some(2):
             self.dataStack.beginAsynchronous { (transaction) -> Void in

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift

@@ -12,7 +12,7 @@ import CoreStore
 
 // MARK: - MigrationsDemoViewController
 
-class MigrationsDemoViewController: UITableViewController {
+class MigrationsDemoViewController: UIViewController {
     
     // MARK: UIViewController
     
@@ -20,10 +20,9 @@ class MigrationsDemoViewController: UITableViewController {
         
         super.viewDidLoad()
         
-        let models = self.models
         if let segmentedControl = self.segmentedControl {
             
-            for (index, model) in models.enumerate() {
+            for (index, model) in self.models.enumerate() {
                 
                 segmentedControl.setTitle(
                     model.label,
@@ -31,55 +30,38 @@ class MigrationsDemoViewController: UITableViewController {
                 )
             }
         }
+        self.setDataStack(nil, model: nil, scrollToSelection: false)
+    }
+    
+    override func viewDidAppear(animated: Bool) {
         
-        let dataStack = DataStack(modelName: "MigrationDemo")
+        super.viewDidAppear(animated)
-        do {
+        
+        let modelMetadata = withExtendedLifetime(DataStack(modelName: "MigrationDemo")) {
+            (dataStack: DataStack) -> ModelMetadata in
             
-            let migrations = try dataStack.requiredMigrationsForSQLiteStore(
+            let models = self.models
-                fileName: "MigrationDemo.sqlite"
+            do {
-            )
-            
-            let storeVersion = migrations.first?.sourceVersion ?? dataStack.modelVersion
-            for model in models {
                 
-                if model.version == storeVersion {
+                let migrations = try dataStack.requiredMigrationsForSQLiteStore(
+                    fileName: "MigrationDemo.sqlite"
+                )
+                
+                let storeVersion = migrations.first?.sourceVersion ?? dataStack.modelVersion
+                for model in models {
                     
-                    self.selectModelVersion(model, animated: false)
+                    if model.version == storeVersion {
-                    return
+                        
+                        return model
+                    }
                 }
             }
+            catch _ { }
+            
+            return models.first!
         }
-        catch _ { }
         
-        self.selectModelVersion(self.models.first!, animated: false)
+        self.selectModelVersion(modelMetadata)
-    }
-    
-
-    // MARK: UITableViewDataSource
-    
-    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        
-        return self.models.count
-    }
-    
-    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
-        
-        let cell = tableView.dequeueReusableCellWithIdentifier("UITableViewCell", forIndexPath: indexPath)
-        cell.textLabel?.text = self.models[indexPath.row].version
-        return cell
-    }
-    
-    
-    // MARK: UITableViewDelegate
-    
-    override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
-        
-        return "Model Versions"
-    }
-
-    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
-        
-        self.selectModelVersion(self.models[indexPath.row], animated: true)
     }
     
     
@@ -111,28 +93,36 @@ class MigrationsDemoViewController: UITableViewController {
         )
     ]
     
-    private var dataStack: DataStack?
+    private var _listMonitor: ListMonitor<NSManagedObject>?
-    private var organism: NSManagedObject?
+    private var listMonitor: ListMonitor<NSManagedObject>? {
+        
+        return self._listMonitor
+    }
     
+    private var _dataStack: DataStack?
+    private var dataStack: DataStack? {
+        
+        return self._dataStack
+    }
+    
+    private var _lastSelectedIndexPath: NSIndexPath?
+    private var lastSelectedIndexPath: NSIndexPath? {
+        
+        return self._lastSelectedIndexPath
+    }
+    
+    private func setSelectedIndexPath(indexPath: NSIndexPath, scrollToSelection: Bool) {
+        
+        self._lastSelectedIndexPath = indexPath
+        self.updateDisplay(reloadData: false, scrollToSelection: scrollToSelection, animated: true)
+    }
+    
+    @IBOutlet private dynamic weak var headerContainer: UIView?
     @IBOutlet private dynamic weak var titleLabel: UILabel?
     @IBOutlet private dynamic weak var organismLabel: UILabel?
     @IBOutlet private dynamic weak var segmentedControl: UISegmentedControl?
     @IBOutlet private dynamic weak var progressView: UIProgressView?
-    
+    @IBOutlet private dynamic weak var tableView: UITableView?
-    @IBAction private dynamic func mutateBarButtonTapped(sender: AnyObject?) {
-        
-        if let dataStack = self.dataStack, let organism = self.organism {
-            
-            dataStack.beginSynchronous { (transaction) -> Void in
-                
-                let organism = transaction.edit(organism)
-                (organism as! OrganismProtocol).mutate()
-                
-                transaction.commit()
-            }
-            self.updateDisplayWithCompletion()
-        }
-    }
     
     @IBAction private dynamic func segmentedControlValueChanged(sender: AnyObject?) {
         
@@ -141,25 +131,24 @@ class MigrationsDemoViewController: UITableViewController {
             return
         }
         
-        self.selectModelVersion(self.models[index], animated: true)
+        self.selectModelVersion(self.models[index])
     }
     
-    private func selectModelVersion(model: ModelMetadata, animated: Bool) {
+    private func selectModelVersion(model: ModelMetadata) {
         
-        if self.organism?.entity.managedObjectClassName == "\(model.entityType)" {
+        if self.dataStack?.modelVersion == model.version {
             
             return
         }
         
-        self.organism = nil
+        self.setDataStack(nil, model: nil, scrollToSelection: false) // explicitly trigger NSPersistentStore cleanup by deallocating the stack
-        self.dataStack = nil
         
         let dataStack = DataStack(
             modelName: "MigrationDemo",
             migrationChain: model.migrationChain
         )
         
-        self.setEnabled(false, animated: animated)
+        self.setEnabled(false)
         let progress = try! dataStack.addSQLiteStore(
             fileName: "MigrationDemo.sqlite",
             completion: { [weak self] (result) -> Void in
@@ -171,57 +160,50 @@ class MigrationsDemoViewController: UITableViewController {
                 
                 guard case .Success = result else {
                     
-                    strongSelf.setEnabled(true, animated: animated)
+                    strongSelf.setEnabled(true)
                     return
                 }
                 
-                strongSelf.dataStack = dataStack
+                strongSelf.setDataStack(dataStack, model: model, scrollToSelection: true)
-                if let organism = dataStack.fetchOne(From(model.entityType)) {
+                
+                let count = dataStack.queryValue(From(model.entityType), Select<Int>(.Count("dna")))
+                if count > 0 {
                     
-                    strongSelf.organism = organism
+                    strongSelf.setEnabled(true)
                 }
                 else {
                     
-                    dataStack.beginSynchronous { (transaction) -> Void in
+                    dataStack.beginAsynchronous { (transaction) -> Void in
                         
-                        for _ in 0 ..< 100000 {
+                        for i: Int64 in 1 ..< 10000 {
                             
-                            let organism = transaction.create(Into(model.entityType))
+                            let organism = transaction.create(Into(model.entityType)) as! OrganismProtocol
-                            (organism as! OrganismProtocol).mutate()
+                            organism.dna = i
+                            organism.mutate()
                         }
                         
-                        transaction.commit()
+                        transaction.commit { result -> Void in
+                            
+                            self?.setEnabled(true)
+                        }
                     }
-                    strongSelf.organism = dataStack.fetchOne(From(model.entityType))!
                 }
-                
-                strongSelf.updateDisplayWithCompletion()
-                
-                let indexOfModel = strongSelf.models.map { $0.version }.indexOf(model.version)!
-                strongSelf.tableView.selectRowAtIndexPath(
-                    NSIndexPath(forRow: indexOfModel, inSection: 0),
-                    animated: false,
-                    scrollPosition: .None
-                )
-                strongSelf.segmentedControl?.selectedSegmentIndex = indexOfModel
-                strongSelf.setEnabled(true, animated: animated)
             }
         )
         
         if let progress = progress {
             
-            self.updateDisplayWithProgress(progress)
             progress.setProgressHandler { [weak self] (progress) -> Void in
                 
-                self?.updateDisplayWithProgress(progress)
+                self?.reloadTableHeaderWithProgress(progress)
             }
         }
     }
     
-    func setEnabled(enabled: Bool, animated: Bool) {
+    private func setEnabled(enabled: Bool) {
         
-        UIView.animateKeyframesWithDuration(
+        UIView.animateWithDuration(
-            animated ? 0.2 : 0,
+            0.2,
             delay: 0,
             options: .BeginFromCurrentState,
             animations: { () -> Void in
@@ -231,6 +213,8 @@ class MigrationsDemoViewController: UITableViewController {
                 navigationItem.rightBarButtonItem?.enabled = enabled
                 navigationItem.hidesBackButton = !enabled
                 
+                self.segmentedControl?.enabled = enabled
+                
                 if let tableView = self.tableView {
                     
                     tableView.alpha = enabled ? 1.0 : 0.5
@@ -241,18 +225,47 @@ class MigrationsDemoViewController: UITableViewController {
         )
     }
     
-    func updateDisplayWithProgress(progress: NSProgress) {
+    private func setDataStack(dataStack: DataStack?, model: ModelMetadata?, scrollToSelection: Bool) {
+        
+        if let dataStack = dataStack, let model = model {
+            
+            self.segmentedControl?.selectedSegmentIndex = self.models.map { $0.version }.indexOf(model.version)!
+            
+            self._dataStack = dataStack
+            let listMonitor = dataStack.monitorList(From(model.entityType), OrderBy(.Descending("dna")))
+            listMonitor.addObserver(self)
+            self._listMonitor = listMonitor
+            
+            if self.lastSelectedIndexPath == nil  {
+                
+                if listMonitor.numberOfObjectsInSection(0) > 0 {
+                    
+                    self.setSelectedIndexPath(NSIndexPath(forRow: 0, inSection: 0), scrollToSelection: true)
+                }
+            }
+        }
+        else {
+           
+            self.segmentedControl?.selectedSegmentIndex = UISegmentedControlNoSegment
+            self._dataStack = nil
+            self._listMonitor = nil
+        }
+        
+        self.updateDisplay(reloadData: true, scrollToSelection: scrollToSelection, animated: false)
+    }
+    
+    private func reloadTableHeaderWithProgress(progress: NSProgress) {
         
         self.progressView?.setProgress(Float(progress.fractionCompleted), animated: true)
         self.titleLabel?.text = "Migrating: \(progress.localizedDescription)"
         self.organismLabel?.text = "Incremental step \(progress.localizedAdditionalDescription)"
     }
     
-    func updateDisplayWithCompletion() {
+    private func updateDisplay(reloadData reloadData: Bool, scrollToSelection: Bool, animated: Bool) {
         
         var lines = [String]()
         var organismType = ""
-        if let organism = self.organism {
+        if let indexPath = self.lastSelectedIndexPath, let organism = self.listMonitor?[indexPath] {
             
             for property in organism.entity.properties {
                 
@@ -265,6 +278,102 @@ class MigrationsDemoViewController: UITableViewController {
         self.titleLabel?.text = organismType
         self.organismLabel?.text = "\n".join(lines)
         self.progressView?.progress = 0
-        self.tableView.tableHeaderView?.setNeedsLayout()
+        
+        self.headerContainer?.setNeedsLayout()
+        
+        guard let tableView = self.tableView else {
+            
+            return
+        }
+        
+        if reloadData {
+            
+            tableView.reloadData()
+        }
+        
+        tableView.layoutIfNeeded()
+        
+        if let indexPath = self.lastSelectedIndexPath where indexPath.row < tableView.numberOfRowsInSection(0) {
+            
+            tableView.selectRowAtIndexPath(indexPath,
+                animated: scrollToSelection && animated,
+                scrollPosition: scrollToSelection ? .Middle : .None
+            )
+        }
+    }
+}
+
+
+// MARK: - MigrationsDemoViewController: ListObserver
+
+extension MigrationsDemoViewController: ListObserver {
+    
+    // MARK: ListObserver
+    
+    func listMonitorWillChange(monitor: ListMonitor<NSManagedObject>) { }
+    
+    func listMonitorDidChange(monitor: ListMonitor<NSManagedObject>) {
+        
+        if self.lastSelectedIndexPath == nil && self.listMonitor?.numberOfObjectsInSection(0) > 0 {
+            
+            self.tableView?.reloadData()
+            self.setSelectedIndexPath(NSIndexPath(forRow: 0, inSection: 0), scrollToSelection: false)
+        }
+        else {
+            
+            self.updateDisplay(reloadData: true, scrollToSelection: true, animated: true)
+        }
+    }
+}
+
+
+// MARK: - MigrationsDemoViewController: UITableViewDataSource, UITableViewDelegate
+
+extension MigrationsDemoViewController: UITableViewDataSource, UITableViewDelegate {
+    
+    // MARK: UITableViewDataSource
+    
+    @objc dynamic func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+        
+        return self.listMonitor?.numberOfObjectsInSection(0) ?? 0
+    }
+    
+    @objc dynamic func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
+        
+        let cell = tableView.dequeueReusableCellWithIdentifier("OrganismTableViewCell", forIndexPath: indexPath) as! OrganismTableViewCell
+        
+        let dna = (self.listMonitor?[indexPath] as? OrganismProtocol)?.dna.description ?? ""
+        cell.dnaLabel?.text = "DNA: \(dna)"
+        cell.mutateButtonHandler = { [weak self] _ -> Void in
+            
+            guard let strongSelf = self,
+                let dataStack = strongSelf.dataStack,
+                let organism = strongSelf.listMonitor?[indexPath] else {
+                    
+                    return
+            }
+            
+            strongSelf.setSelectedIndexPath(indexPath, scrollToSelection: false)
+            strongSelf.setEnabled(false)
+            dataStack.beginAsynchronous { (transaction) -> Void in
+                
+                let organism = transaction.edit(organism) as! OrganismProtocol
+                organism.mutate()
+                
+                transaction.commit { _ -> Void in
+                    
+                    self?.setEnabled(true)
+                }
+            }
+        }
+        return cell
+    }
+    
+    
+    // MARK: UITableViewDelegate
+    
+    @objc dynamic func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
+        
+        self.setSelectedIndexPath(indexPath, scrollToSelection: false)
     }
 }

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/OrganismProtocol.swift

@@ -8,7 +8,9 @@
 
 import Foundation
 
-protocol OrganismProtocol {
+protocol OrganismProtocol: class {
+    
+    var dna: Int64 { get set }
     
     func mutate()
 }

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/OrganismTableViewCell.swift

@@ -0,0 +1,22 @@
+//
+//  OrganismTableViewCell.swift
+//  CoreStoreDemo
+//
+//  Created by John Rommel Estropia on 2015/07/12.
+//  Copyright © 2015 John Rommel Estropia. All rights reserved.
+//
+
+import UIKit
+
+class OrganismTableViewCell: UITableViewCell {
+
+    @IBOutlet weak dynamic var dnaLabel: UILabel?
+    @IBOutlet weak dynamic var mutateButton: UIButton?
+    
+    var mutateButtonHandler: (() -> Void)?
+
+    @IBAction dynamic func mutateButtonTouchUpInside(sender: UIButton?) {
+     
+        self.mutateButtonHandler?()
+    }
+}

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/OrganismV1.swift

@@ -11,6 +11,7 @@ import CoreData
 
 class OrganismV1: NSManagedObject, OrganismProtocol {
 
+    @NSManaged var dna: Int64
     @NSManaged var hasHead: Bool
     @NSManaged var hasTail: Bool
     

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/OrganismV2.swift

@@ -10,7 +10,8 @@ import Foundation
 import CoreData
 
 class OrganismV2: NSManagedObject, OrganismProtocol {
-
+    
+    @NSManaged var dna: Int64
     @NSManaged var hasHead: Bool
     @NSManaged var hasTail: Bool
     @NSManaged var numberOfFlippers: Int32

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/OrganismV3.swift

@@ -10,7 +10,8 @@ import Foundation
 import CoreData
 
 class OrganismV3: NSManagedObject, OrganismProtocol {
-
+    
+    @NSManaged var dna: Int64
     @NSManaged var hasHead: Bool
     @NSManaged var hasTail: Bool
     @NSManaged var numberOfLimbs: Int32

CoreStoreDemo/CoreStoreDemo/MigrationDemo.xcdatamodeld/MigrationDemo.xcdatamodel/contents

@@ -1,10 +1,11 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="7701" systemVersion="14D136" minimumToolsVersion="Xcode 4.3" macOSVersion="Automatic" iOSVersion="Automatic">
+<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="7701" systemVersion="14E46" minimumToolsVersion="Xcode 4.3">
     <entity name="Organism" representedClassName="CoreStoreDemo.OrganismV1" syncable="YES">
+        <attribute name="dna" optional="YES" attributeType="Integer 64" syncable="YES"/>
         <attribute name="hasHead" optional="YES" attributeType="Boolean" syncable="YES"/>
         <attribute name="hasTail" optional="YES" attributeType="Boolean" syncable="YES"/>
     </entity>
     <elements>
-        <element name="Organism" positionX="-36" positionY="9" width="128" height="75"/>
+        <element name="Organism" positionX="-36" positionY="9" width="128" height="90"/>
     </elements>
 </model>

CoreStoreDemo/CoreStoreDemo/MigrationDemo.xcdatamodeld/MigrationDemoV2.xcdatamodel/contents

@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="8118.20" systemVersion="14D136" minimumToolsVersion="Xcode 4.3">
+<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="7701" systemVersion="14E46" minimumToolsVersion="Xcode 4.3">
     <entity name="Organism" representedClassName="CoreStoreDemo.OrganismV2" syncable="YES">
+        <attribute name="dna" optional="YES" attributeType="Integer 64" syncable="YES"/>
         <attribute name="hasHead" attributeType="Boolean" syncable="YES"/>
         <attribute name="hasTail" attributeType="Boolean" syncable="YES"/>
         <attribute name="numberOfFlippers" attributeType="Integer 32" defaultValueString="0" syncable="YES"/>
     </entity>
     <elements>
-        <element name="Organism" positionX="-36" positionY="9" width="128" height="90"/>
+        <element name="Organism" positionX="-36" positionY="9" width="128" height="105"/>
     </elements>
 </model>

CoreStoreDemo/CoreStoreDemo/MigrationDemo.xcdatamodeld/MigrationDemoV3.xcdatamodel/contents

@@ -1,12 +1,13 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="8118.20" systemVersion="14D136" minimumToolsVersion="Xcode 4.3">
+<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="7701" systemVersion="14E46" minimumToolsVersion="Xcode 4.3">
     <entity name="Organism" representedClassName="CoreStoreDemo.OrganismV3" syncable="YES">
+        <attribute name="dna" optional="YES" attributeType="Integer 64" syncable="YES"/>
         <attribute name="hasHead" attributeType="Boolean" syncable="YES"/>
         <attribute name="hasTail" attributeType="Boolean" syncable="YES"/>
         <attribute name="hasVertebrae" attributeType="Boolean" syncable="YES"/>
         <attribute name="numberOfLimbs" attributeType="Integer 32" defaultValueString="0" syncable="YES"/>
     </entity>
     <elements>
-        <element name="Organism" positionX="-36" positionY="9" width="128" height="105"/>
+        <element name="Organism" positionX="-36" positionY="9" width="128" height="120"/>
     </elements>
 </model>

CoreStoreDemo/CoreStoreDemo/Stack Setup Demo/StackSetupDemoViewController.swift

@@ -18,12 +18,12 @@ private struct Static {
     static let facebookStack: DataStack = {
         
         let dataStack = DataStack(modelName: "StackSetupDemo")
-        dataStack.addSQLiteStoreAndWait(
+        try! dataStack.addSQLiteStoreAndWait(
             fileName: "AccountsDemo_FB_Male.sqlite",
             configuration: maleConfiguration,
             resetStoreOnMigrationFailure: true
         )
-        dataStack.addSQLiteStoreAndWait(
+        try! dataStack.addSQLiteStoreAndWait(
             fileName: "AccountsDemo_FB_Female.sqlite",
             configuration: femaleConfiguration,
             resetStoreOnMigrationFailure: true
@@ -52,12 +52,12 @@ private struct Static {
     static let twitterStack: DataStack = {
         
         let dataStack = DataStack(modelName: "StackSetupDemo")
-        dataStack.addSQLiteStoreAndWait(
+        try! dataStack.addSQLiteStoreAndWait(
             fileName: "AccountsDemo_TW_Male.sqlite",
             configuration: maleConfiguration,
             resetStoreOnMigrationFailure: true
         )
-        dataStack.addSQLiteStoreAndWait(
+        try! dataStack.addSQLiteStoreAndWait(
             fileName: "AccountsDemo_TW_Female.sqlite",
             configuration: femaleConfiguration,
             resetStoreOnMigrationFailure: true

CoreStoreDemo/CoreStoreDemo/Transactions Demo/TransactionsDemoViewController.swift

@@ -18,7 +18,7 @@ private struct Static {
     
     static let placeController: ObjectMonitor<Place> = {
         
-        CoreStore.addSQLiteStoreAndWait(
+        try! CoreStore.addSQLiteStoreAndWait(
             fileName: "PlaceDemo.sqlite",
             configuration: "TransactionsDemo",
             resetStoreOnMigrationFailure: true

CoreStoreTests/CoreStoreTests.swift

@@ -47,22 +47,22 @@ class CoreStoreTests: XCTestCase {
         CoreStore.defaultStack = stack
         XCTAssert(CoreStore.defaultStack === stack, "CoreStore.defaultStack === stack")
         
-        switch stack.addSQLiteStoreAndWait(fileName: "ConfigStore1.sqlite", configuration: "Config1", resetStoreOnMigrationFailure: true){
+        do {
+            
+            try stack.addSQLiteStoreAndWait(fileName: "ConfigStore1.sqlite", configuration: "Config1", resetStoreOnMigrationFailure: true)
+        }
+        catch let error as NSError {
             
-        case .Failure(let error):
             XCTFail(error.description)
-            
-        default:
-            break
         }
         
-        switch stack.addSQLiteStoreAndWait(fileName: "ConfigStore2.sqlite", configuration: "Config2", resetStoreOnMigrationFailure: true){
+        do {
+            
+            try stack.addSQLiteStoreAndWait(fileName: "ConfigStore2.sqlite", configuration: "Config2", resetStoreOnMigrationFailure: true)
+        }
+        catch let error as NSError {
             
-        case .Failure(let error):
             XCTFail(error.description)
-            
-        default:
-            break
         }
         
         let detachedTransaction = CoreStore.beginDetached()

README.md

@@ -43,7 +43,12 @@ I wrote this library when Swift was made public, and CoreStore is now a powerhou
 
 Quick-setup:
 ```swift
-CoreStore.addSQLiteStoreAndWait(fileName: "MyStore.sqlite")
+do {
+    try CoreStore.addSQLiteStoreAndWait(fileName: "MyStore.sqlite")
+}
+catch {
+    // ...
+}
 ```
 
 Simple transactions:
@@ -131,7 +136,12 @@ This allows for a butter-smooth main thread, while still taking advantage of saf
 ## Setting up
 The simplest way to initialize CoreStore is to add a default store to the default stack:
 ```swift
-CoreStore.addSQLiteStoreAndWait()
+do {
+    try CoreStore.addSQLiteStoreAndWait()
+}
+catch {
+    // ...
+}
 ```
 This one-liner does the following:
 - Triggers the lazy-initialization of `CoreStore.defaultStack` with a default `DataStack`
@@ -143,21 +153,24 @@ For most cases, this configuration is usable as it is. But for more hardcore set
 ```swift
 let dataStack = DataStack(modelName: "MyModel") // loads from the "MyModel.xcdatamodeld" file
 
-switch dataStack.addInMemoryStore(configuration: "Config1") { // creates an in-memory store with entities from the "Config1" configuration in the .xcdatamodeld file
+do {
-case .Success(let persistentStore): // persistentStore is an NSPersistentStore instance
+    // creates an in-memory store with entities from the "Config1" configuration in the .xcdatamodeld file
+    let persistentStore = try dataStack.addInMemoryStore(configuration: "Config1") // persistentStore is an NSPersistentStore instance
     print("Successfully created an in-memory store: \(persistentStore)"
-case .Failure(let error): // error is an NSError instance
+}
+catch let error as NSError {
     print("Failed creating an in-memory store with error: \(error.description)"
 }
 
-switch dataStack.addSQLiteStoreAndWait(
+do {
-    fileURL: sqliteFileURL, // set the target file URL for the sqlite file
+    try dataStack.addSQLiteStoreAndWait(
-    configuration: "Config2", // use entities from the "Config2" configuration in the .xcdatamodeld file
+        fileURL: sqliteFileURL, // set the target file URL for the sqlite file
-    automigrating: true, // automatically run lightweight migrations or entity policy migrations when needed
+        configuration: "Config2", // use entities from the "Config2" configuration in the .xcdatamodeld file
-    resetStoreOnMigrationFailure: true) { // delete and recreate the sqlite file when migration conflicts occur (useful when debugging)
+        automigrating: true, // automatically run lightweight migrations or entity policy migrations when needed
-case .Success(let persistentStore): // persistentStore is an NSPersistentStore instance
+        resetStoreOnMigrationFailure: true)
     print("Successfully created an sqlite store: \(persistentStore)"
-case .Failure(let error): // error is an NSError instance
+}
+catch let error as NSError {
     print("Failed creating an sqlite store with error: \(error.description)"
 }
 
@@ -173,7 +186,11 @@ class MyViewController: UIViewController {
     let dataStack = DataStack(modelName: "MyModel")
     override func viewDidLoad() {
         super.viewDidLoad()
-        self.dataStack.addSQLiteStoreAndWait()
+        do {
+            try self.dataStack.addSQLiteStoreAndWait()
+        }
+        catch { // ...
+        }
     }
     func methodToBeCalledLaterOn() {
         let objects = self.dataStack.fetchAll(From(MyEntity))
@@ -186,7 +203,11 @@ The difference is when you set the stack as the `CoreStore.defaultStack`, you ca
 class MyViewController: UIViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
-        CoreStore.addSQLiteStoreAndWait()
+        do {
+            try CoreStore.addSQLiteStoreAndWait()
+        }
+        catch { // ...
+        }
     }
     func methodToBeCalledLaterOn() {
         let objects = CoreStore.fetchAll(From(MyEntity))