fetches, queries, and deletes are now throwable methods

CoreStoreDemo/CoreStoreDemo/AppDelegate.swift

@@ -20,7 +20,6 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]? = nil) -> Bool {
         
-        application.statusBarStyle = .lightContent
         return true
     }
 }

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

@@ -25,7 +25,7 @@ private struct Static {
         _ = try? dataStack.perform(
             synchronous: { (transaction) in
                 
-                transaction.deleteAll(From<TimeZone>())
+                try transaction.deleteAll(From<TimeZone>())
                 
                 for name in NSTimeZone.knownTimeZoneNames {
                     
@@ -164,17 +164,17 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
             title: "All Time Zones",
             fetch: { () -> [TimeZone] in
                 
-                return Static.timeZonesStack.fetchAll(
+                return try! Static.timeZonesStack.fetchAll(
                     From<TimeZone>()
                         .orderBy(.ascending(\.name))
-                )!
+                )
             }
         ),
         (
             title: "Time Zones in Asia",
             fetch: { () -> [TimeZone] in
                 
-                return Static.timeZonesStack.fetchAll(
+                return try! Static.timeZonesStack.fetchAll(
                     From<TimeZone>()
                         .where(
                             format: "%K BEGINSWITH[c] %@",
@@ -182,14 +182,14 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
                             "Asia"
                         )
                         .orderBy(.ascending(\.secondsFromGMT))
-                )!
+                )
             }
         ),
         (
             title: "Time Zones in America and Europe",
             fetch: { () -> [TimeZone] in
                 
-                return Static.timeZonesStack.fetchAll(
+                return try! Static.timeZonesStack.fetchAll(
                     From<TimeZone>()
                         .where(
                             format: "%K BEGINSWITH[c] %@ OR %K BEGINSWITH[c] %@",
@@ -199,14 +199,14 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
                             "Europe"
                         )
                         .orderBy(.ascending(\.secondsFromGMT))
-                )!
+                )
             }
         ),
         (
             title: "All Time Zones Except America",
             fetch: { () -> [TimeZone] in
                 
-                return Static.timeZonesStack.fetchAll(
+                return try! Static.timeZonesStack.fetchAll(
                     From<TimeZone>()
                         .where(
                             format: "%K BEGINSWITH[c] %@",
@@ -214,18 +214,18 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
                             "America"
                         )
                         .orderBy(.ascending(\.secondsFromGMT))
-                    )!
+                    )
             }
         ),
         (
             title: "Time Zones with Summer Time",
             fetch: { () -> [TimeZone] in
                 
-                return Static.timeZonesStack.fetchAll(
+                return try! Static.timeZonesStack.fetchAll(
                     From<TimeZone>()
                         .where(\.hasDaylightSavingTime == true)
                         .orderBy(.ascending(\.name))
-                )!
+                )
             }
         )
     ]
@@ -235,28 +235,28 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
             title: "Number of Time Zones",
             query: { () -> Any in
                 
-                return Static.timeZonesStack.queryValue(
+                return try! Static.timeZonesStack.queryValue(
                     From<TimeZone>()
                         .select(NSNumber.self, .count(\.name))
-                )! as Any
+                )!
             }
         ),
         (
             title: "Abbreviation For Tokyo's Time Zone",
             query: { () -> Any in
                 
-                return Static.timeZonesStack.queryValue(
+                return try! Static.timeZonesStack.queryValue(
                     From<TimeZone>()
                         .select(String.self, .attribute(\.abbreviation))
                         .where(format: "%K ENDSWITH[c] %@", #keyPath(TimeZone.name), "Tokyo")
-                )! as Any
+                )!
             }
         ),
         (
             title: "All Abbreviations",
             query: { () -> Any in
                 
-                return Static.timeZonesStack.queryAttributes(
+                return try! Static.timeZonesStack.queryAttributes(
                     From<TimeZone>()
                         .select(
                             NSDictionary.self,
@@ -264,14 +264,14 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
                             .attribute(\.abbreviation)
                         )
                         .orderBy(.ascending(\.name))
-                )!
+                )
             }
         ),
         (
             title: "Number of Countries per Time Zone",
             query: { () -> Any in
                 
-                return Static.timeZonesStack.queryAttributes(
+                return try! Static.timeZonesStack.queryAttributes(
                     From<TimeZone>()
                         .select(
                             NSDictionary.self,
@@ -283,14 +283,14 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
                             .ascending(\.secondsFromGMT),
                             .ascending(\.name)
                         )
-                )!
+                )
             }
         ),
         (
             title: "Number of Countries with Summer Time",
             query: { () -> Any in
                 
-                return Static.timeZonesStack.queryAttributes(
+                return try! Static.timeZonesStack.queryAttributes(
                     From<TimeZone>()
                         .select(
                             NSDictionary.self,
@@ -302,7 +302,7 @@ class FetchingAndQueryingDemoViewController: UIViewController, UITableViewDataSo
                             .descending(\.hasDaylightSavingTime),
                             .ascending(\.name)
                         )
-                )!
+                )
             }
         )
     ]

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

@@ -160,7 +160,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
 
     override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         
-        return ColorsDemo.palettes.numberOfObjectsInSection(section)
+        return ColorsDemo.palettes.numberOfObjects(in: section)
     }
     
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
@@ -208,7 +208,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
     
     override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
         
-        return ColorsDemo.palettes.sectionInfoAtIndex(section).name
+        return ColorsDemo.palettes.sectionInfo(at: section).name
     }
     
     
@@ -288,7 +288,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
         ColorsDemo.stack.perform(
             asynchronous: { (transaction) in
                 
-                transaction.deleteAll(From<Palette>())
+                try transaction.deleteAll(From<Palette>())
             },
             completion: { _ in }
         )
@@ -316,7 +316,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
         ColorsDemo.stack.perform(
             asynchronous: { (transaction) in
 
-                for palette in (transaction.fetchAll(From<Palette>()) ?? []) {
+                for palette in try transaction.fetchAll(From<Palette>()) {
 
                     palette.hue .= Palette.randomHue()
                     palette.colorName .= nil

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

@@ -50,7 +50,7 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
     
     required init?(coder aDecoder: NSCoder) {
         
-        if let palette = ColorsDemo.stack.fetchOne(From<Palette>().orderBy(.ascending(\.hue))) {
+        if let palette = try! ColorsDemo.stack.fetchOne(From<Palette>().orderBy(.ascending(\.hue))) {
             
             self.monitor = ColorsDemo.stack.monitorObject(palette)
         }
@@ -64,7 +64,7 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
                 }
             )
             
-            let palette = ColorsDemo.stack.fetchOne(From<Palette>().orderBy(.ascending(\.hue)))!
+            let palette = try! ColorsDemo.stack.fetchOne(From<Palette>().orderBy(.ascending(\.hue)))!
             self.monitor = ColorsDemo.stack.monitorObject(palette)
         }
         

CoreStoreDemo/CoreStoreDemo/Loggers Demo/CustomLoggerViewController.swift

@@ -116,7 +116,7 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
         case 2?:
             DispatchQueue.global(qos: .background).async {
                 
-                _ = self.dataStack.fetchOne(From<Place>())
+                _ = try! self.dataStack.fetchOne(From<Place>())
             }
             
         default:

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift

@@ -79,7 +79,7 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
     func listMonitorDidChange(_ monitor: ListMonitor<NSManagedObject>) {
         
         if self.lastSelectedIndexPath == nil,
-            let numberOfObjectsInSection = self.listMonitor?.numberOfObjectsInSection(0),
+            let numberOfObjectsInSection = self.listMonitor?.numberOfObjects(in: 0),
             numberOfObjectsInSection > 0 {
             
             self.tableView?.reloadData()
@@ -100,7 +100,7 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
     
     @objc dynamic func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         
-        return self.listMonitor?.numberOfObjectsInSection(0) ?? 0
+        return self.listMonitor?.numberOfObjects(in: 0) ?? 0
     }
     
     @objc dynamic func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
@@ -286,7 +286,7 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
                 
                 self.set(dataStack: dataStack, model: model, scrollToSelection: true)
                 
-                let count = dataStack.queryValue(
+                let count = try! dataStack.queryValue(
                     From<NSManagedObject>(model.entityType)
                         .select(Int.self, .count(#keyPath(OrganismV1.dna))))!
                 if count > 0 {
@@ -378,7 +378,7 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
             
             if self.lastSelectedIndexPath == nil  {
                 
-                if listMonitor.numberOfObjectsInSection(0) > 0 {
+                if listMonitor.numberOfObjects(in: 0) > 0 {
                     
                     self.setSelectedIndexPath(IndexPath(row: 0, section: 0), scrollToSelection: true)
                 }

CoreStoreDemo/CoreStoreDemo/Stack Setup Demo/StackSetupDemoViewController.swift

@@ -36,7 +36,7 @@ private struct Static {
         _ = try? dataStack.perform(
             synchronous: { (transaction) in
                 
-                transaction.deleteAll(From<UserAccount>())
+                try transaction.deleteAll(From<UserAccount>())
                 
                 let account1 = transaction.create(Into<MaleAccount>(maleConfiguration))
                 account1.accountType = "Facebook"
@@ -74,7 +74,7 @@ private struct Static {
         _ = try? dataStack.perform(
             synchronous: { (transaction) in
                 
-                transaction.deleteAll(From<UserAccount>())
+                try transaction.deleteAll(From<UserAccount>())
                 
                 let account1 = transaction.create(Into<MaleAccount>(maleConfiguration))
                 account1.accountType = "Twitter"
@@ -99,8 +99,8 @@ private struct Static {
 class StackSetupDemoViewController: UITableViewController {
     
     let accounts = [
-        Static.facebookStack.fetchAll(From(UserAccount.self)) ?? [],
-        Static.twitterStack.fetchAll(From(UserAccount.self)) ?? []
+        try! Static.facebookStack.fetchAll(From<UserAccount>()),
+        try! Static.twitterStack.fetchAll(From<UserAccount>())
     ]
     
     

CoreStoreDemo/CoreStoreDemo/Transactions Demo/TransactionsDemoViewController.swift

@@ -26,7 +26,7 @@ private struct Static {
             )
         )
         
-        var place = CoreStore.fetchOne(From<Place>())
+        var place = try! CoreStore.fetchOne(From<Place>())
         if place == nil {
             
             _ = try? CoreStore.perform(
@@ -36,7 +36,7 @@ private struct Static {
                     place.setInitialValues()
                 }
             )
-            place = CoreStore.fetchOne(From<Place>())
+            place = try! CoreStore.fetchOne(From<Place>())
         }
         
         return CoreStore.monitorObject(place!)

CoreStoreTests/BaseTests/BaseTestCase.swift

@@ -36,8 +36,7 @@ class BaseTestCase: XCTestCase {
     // MARK: Internal
     
     @nonobjc
-    @discardableResult
-    func prepareStack<T>(configurations: [ModelConfiguration] = [nil], _ closure: (_ dataStack: DataStack) -> T) -> T {
+    func prepareStack(configurations: [ModelConfiguration] = [nil], _ closure: (_ dataStack: DataStack) throws -> Void) {
         
         let stack = DataStack(
             xcodeModelName: "Model",
@@ -57,16 +56,16 @@ class BaseTestCase: XCTestCase {
                     )
                 )
             }
+            try closure(stack)
         }
         catch let error as NSError {
             
             XCTFail(error.coreStoreDumpString)
         }
-        return closure(stack)
     }
     
     @nonobjc
-    func expectLogger<T>(_ expectations: [TestLogger.Expectation], closure: () -> T) -> T {
+    func expectLogger<T>(_ expectations: [TestLogger.Expectation], closure: () throws -> T) rethrows -> T {
         
         CoreStore.logger = TestLogger(self.prepareLoggerExpectations(expectations))
         defer {
@@ -74,7 +73,7 @@ class BaseTestCase: XCTestCase {
             self.checkExpectationsImmediately()
             CoreStore.logger = TestLogger([:])
         }
-        return closure()
+        return try closure()
     }
     
     @nonobjc

CoreStoreTests/DynamicModelTests.swift

@@ -248,51 +248,51 @@ class DynamicModelTests: BaseTestDataTestCase {
                     let p1 = Where<Animal>({ $0.species == "Sparrow" })
                     XCTAssertEqual(p1.predicate, NSPredicate(format: "%K == %@", "species", "Sparrow"))
                     
-                    let bird = transaction.fetchOne(From<Animal>(), p1)
+                    let bird = try transaction.fetchOne(From<Animal>(), p1)
                     XCTAssertNotNil(bird)
                     XCTAssertEqual(bird!.species.value, "Sparrow")
                     
                     let p2 = Where<Dog>({ $0.nickname == "Spot" })
                     XCTAssertEqual(p2.predicate, NSPredicate(format: "%K == %@", "nickname", "Spot"))
                     
-                    let dog = transaction.fetchOne(From<Dog>().where(\.nickname == "Spot"))
+                    let dog = try transaction.fetchOne(From<Dog>().where(\.nickname == "Spot"))
                     XCTAssertNotNil(dog)
                     XCTAssertEqual(dog!.nickname.value, "Spot")
                     XCTAssertEqual(dog!.species.value, "Dog")
                     
-                    let person = transaction.fetchOne(From<Person>())
+                    let person = try transaction.fetchOne(From<Person>())
                     XCTAssertNotNil(person)
                     XCTAssertEqual(person!.pets.value.first, dog)
                     
                     let p3 = Where<Dog>({ $0.age == 10 })
                     XCTAssertEqual(p3.predicate, NSPredicate(format: "%K == %d", "age", 10))
                     
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>()
                             .where(\Animal.species == "Dog" && \.age == 10)
                     )
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>()
                             .where(\.age == 10 && \Animal.species == "Dog")
                             .orderBy(.ascending({ $0.species }))
                     )
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>(),
                         Where<Dog>({ $0.age > 10 && $0.age <= 15 })
                     )
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>(),
                         Where<Dog>({ $0.species == "Dog" && $0.age == 10 })
                     )
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>(),
                         Where<Dog>({ $0.age == 10 && $0.species == "Dog" })
                     )
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>(),
                         Where<Dog>({ $0.age > 10 && $0.age <= 15 })
                     )
-                    _ = transaction.fetchAll(
+                    _ = try transaction.fetchAll(
                         From<Dog>(),
                         (\Dog.age > 10 && \Dog.age <= 15)
                     )

CoreStoreTests/FromTests.swift

@@ -75,8 +75,7 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -90,11 +89,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -116,8 +115,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -131,8 +130,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -146,11 +145,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config2")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -164,11 +163,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -182,11 +181,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -200,11 +199,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config2")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -226,8 +225,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -241,8 +240,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -256,11 +255,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config2")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -274,8 +273,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -289,11 +288,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -307,11 +306,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config2")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -333,8 +332,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -348,8 +347,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -363,11 +362,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity1>("Config2")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -381,8 +380,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>()
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -396,11 +395,11 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config1")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = self.expectLogger([.logWarning]) {
+                let storesFound: Void? = try? self.expectLogger([.logError]) {
                     
-                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                    try from.applyToFetchRequest(request, context: dataStack.mainContext)
                 }
-                XCTAssertFalse(storesFound)
+                XCTAssertNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 
@@ -414,8 +413,8 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config2")
                 
                 let request = CoreStoreFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
-                XCTAssertTrue(storesFound)
+                let storesFound: Void? = try? from.applyToFetchRequest(request, context: dataStack.mainContext)
+                XCTAssertNotNil(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.safeAffectedStores)
                 

CoreStoreTests/GroupByTests.swift

@@ -69,7 +69,7 @@ final class GroupByTests: BaseTestCase {
             let groupBy = GroupBy<NSManagedObject>(#keyPath(TestEntity1.testString))
             
             let request = CoreStoreFetchRequest()
-            _ = From<TestEntity1>().applyToFetchRequest(request, context: dataStack.mainContext)
+            try From<TestEntity1>().applyToFetchRequest(request, context: dataStack.mainContext)
             groupBy.applyToFetchRequest(request)
             
             XCTAssertNotNil(request.propertiesToGroupBy)

CoreStoreTests/ImportTests.swift

@@ -95,7 +95,7 @@ class ImportTests: BaseTestDataTestCase {
                             ]
                         )
                         XCTAssertNil(object)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 0)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 0)
                     }
                 )
             }
@@ -103,7 +103,7 @@ class ImportTests: BaseTestDataTestCase {
                 
                 XCTFail()
             }
-            XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 0)
+            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 0)
         }
     }
     
@@ -137,9 +137,9 @@ class ImportTests: BaseTestDataTestCase {
                         catch _ as TestInsertError {
                             
                             errorExpectation.fulfill()
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
                             
-                            let object = transaction.fetchOne(From<TestEntity1>())
+                            let object = try transaction.fetchOne(From<TestEntity1>())
                             XCTAssertNotNil(object)
                             XCTAssertNil(object?.testEntityID)
                             XCTAssertNil(object?.testBoolean)
@@ -182,7 +182,7 @@ class ImportTests: BaseTestDataTestCase {
                             ]
                         )
                         XCTAssertNotNil(object)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
                         XCTAssertNil(object?.testEntityID)
                         XCTAssertEqual(object?.testBoolean, NSNumber(value: true))
                         XCTAssertEqual(object?.testNumber, NSNumber(value: 1))
@@ -202,7 +202,7 @@ class ImportTests: BaseTestDataTestCase {
                                 #keyPath(TestEntity1.testDate): self.dateFormatter.date(from: "2000-01-02T00:00:00Z")!
                             ]
                         )
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
                         XCTAssertNil(object?.testEntityID)
                         XCTAssertEqual(object?.testBoolean, NSNumber(value: false))
                         XCTAssertEqual(object?.testNumber, NSNumber(value: 2))
@@ -254,7 +254,7 @@ class ImportTests: BaseTestDataTestCase {
                             sourceArray: sourceArray
                         )
                         XCTAssertEqual(objects.count, 1)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
                         
                         let object = objects[0]
                         let dictionary = sourceArray[1]
@@ -316,9 +316,9 @@ class ImportTests: BaseTestDataTestCase {
                         catch _ as TestInsertError {
                             
                             errorExpectation.fulfill()
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
                             
-                            let object = transaction.fetchOne(From<TestEntity1>())
+                            let object = try transaction.fetchOne(From<TestEntity1>())
                             XCTAssertNotNil(object)
                             XCTAssertNil(object?.testEntityID)
                             XCTAssertNil(object?.testBoolean)
@@ -372,7 +372,7 @@ class ImportTests: BaseTestDataTestCase {
                             sourceArray: sourceArray
                         )
                         XCTAssertEqual(objects.count, sourceArray.count)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 2)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 2)
                         
                         for i in 0 ..< sourceArray.count {
                             
@@ -424,7 +424,7 @@ class ImportTests: BaseTestDataTestCase {
                                 ]
                             )
                             XCTAssertNil(object)
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 5)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 5)
                         }
                         do {
                             
@@ -442,20 +442,19 @@ class ImportTests: BaseTestDataTestCase {
                                 ]
                             )
                             XCTAssertNil(object)
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 5)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 5)
                             
-                            let existingObjects = transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
-                            XCTAssertNotNil(existingObjects)
-                            XCTAssertEqual(existingObjects?.count, 1)
+                            let existingObjects = try transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
+                            XCTAssertEqual(existingObjects.count, 1)
                             
-                            let existingObject = existingObjects?[0]
-                            XCTAssertEqual(existingObject?.testEntityID, NSNumber(value: 105))
-                            XCTAssertEqual(existingObject?.testBoolean, NSNumber(value: true))
-                            XCTAssertEqual(existingObject?.testNumber, NSNumber(value: 5))
-                            XCTAssertEqual(existingObject?.testDecimal, NSDecimalNumber(string: "5"))
-                            XCTAssertEqual(existingObject?.testString, "nil:TestEntity1:5")
-                            XCTAssertEqual(existingObject?.testData, ("nil:TestEntity1:5" as NSString).data(using: String.Encoding.utf8.rawValue)!)
-                            XCTAssertEqual(existingObject?.testDate, self.dateFormatter.date(from: "2000-01-05T00:00:00Z")!)
+                            let existingObject = existingObjects[0]
+                            XCTAssertEqual(existingObject.testEntityID, NSNumber(value: 105))
+                            XCTAssertEqual(existingObject.testBoolean, NSNumber(value: true))
+                            XCTAssertEqual(existingObject.testNumber, NSNumber(value: 5))
+                            XCTAssertEqual(existingObject.testDecimal, NSDecimalNumber(string: "5"))
+                            XCTAssertEqual(existingObject.testString, "nil:TestEntity1:5")
+                            XCTAssertEqual(existingObject.testData, ("nil:TestEntity1:5" as NSString).data(using: String.Encoding.utf8.rawValue)!)
+                            XCTAssertEqual(existingObject.testDate, self.dateFormatter.date(from: "2000-01-05T00:00:00Z")!)
                         }
                     }
                 )
@@ -504,7 +503,7 @@ class ImportTests: BaseTestDataTestCase {
                         )
                         
                         XCTAssertEqual(objects.count, 1)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                         
                         let object = objects[0]
                         let dictionary = sourceArray[1]
@@ -618,9 +617,9 @@ class ImportTests: BaseTestDataTestCase {
                         catch _ as TestInsertError {
                             
                             errorExpectation.fulfill()
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                             
-                            let object = transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106))
+                            let object = try transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106))
                             XCTAssertNotNil(object)
                             XCTAssertEqual(object?.testEntityID, NSNumber(value: 106))
                             XCTAssertNil(object?.testBoolean)
@@ -657,21 +656,19 @@ class ImportTests: BaseTestDataTestCase {
                         catch _ as TestUpdateError {
                             
                             errorExpectation.fulfill()
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                             
-                            let existingObjects = transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
-                            XCTAssertNotNil(existingObjects)
-                            XCTAssertEqual(existingObjects?.count, 1)
+                            let existingObjects = try transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
+                            XCTAssertEqual(existingObjects.count, 1)
                             
-                            let existingObject = existingObjects?[0]
-                            XCTAssertNotNil(existingObject)
-                            XCTAssertEqual(existingObject?.testEntityID, NSNumber(value: 105))
-                            XCTAssertEqual(existingObject?.testBoolean, NSNumber(value: true))
-                            XCTAssertEqual(existingObject?.testNumber, NSNumber(value: 5))
-                            XCTAssertEqual(existingObject?.testDecimal, NSDecimalNumber(string: "5"))
-                            XCTAssertEqual(existingObject?.testString, "nil:TestEntity1:5")
-                            XCTAssertEqual(existingObject?.testData, ("nil:TestEntity1:5" as NSString).data(using: String.Encoding.utf8.rawValue)!)
-                            XCTAssertEqual(existingObject?.testDate, self.dateFormatter.date(from: "2000-01-05T00:00:00Z")!)
+                            let existingObject = existingObjects[0]
+                            XCTAssertEqual(existingObject.testEntityID, NSNumber(value: 105))
+                            XCTAssertEqual(existingObject.testBoolean, NSNumber(value: true))
+                            XCTAssertEqual(existingObject.testNumber, NSNumber(value: 5))
+                            XCTAssertEqual(existingObject.testDecimal, NSDecimalNumber(string: "5"))
+                            XCTAssertEqual(existingObject.testString, "nil:TestEntity1:5")
+                            XCTAssertEqual(existingObject.testData, ("nil:TestEntity1:5" as NSString).data(using: String.Encoding.utf8.rawValue)!)
+                            XCTAssertEqual(existingObject.testDate, self.dateFormatter.date(from: "2000-01-05T00:00:00Z")!)
                         }
                         self.checkExpectationsImmediately()
                     }
@@ -710,7 +707,7 @@ class ImportTests: BaseTestDataTestCase {
                                 ]
                             )
                             XCTAssertNotNil(object)
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                             
                             XCTAssertEqual(object?.testEntityID, NSNumber(value: 106))
                             XCTAssertEqual(object?.testBoolean, NSNumber(value: true))
@@ -735,7 +732,7 @@ class ImportTests: BaseTestDataTestCase {
                                     ]
                             )
                             XCTAssertNotNil(object)
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                             
                             XCTAssertEqual(object?.testEntityID, NSNumber(value: 106))
                             XCTAssertEqual(object?.testBoolean, NSNumber(value: false))
@@ -745,11 +742,10 @@ class ImportTests: BaseTestDataTestCase {
                             XCTAssertEqual(object?.testData, ("nil:TestEntity1:7" as NSString).data(using: String.Encoding.utf8.rawValue)!)
                             XCTAssertEqual(object?.testDate, self.dateFormatter.date(from: "2000-01-07T00:00:00Z")!)
                             
-                            let existingObjects = transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106))
-                            XCTAssertNotNil(existingObjects)
-                            XCTAssertEqual(existingObjects?.count, 1)
+                            let existingObjects = try transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106))
+                            XCTAssertEqual(existingObjects.count, 1)
                             
-                            let existingObject = existingObjects?[0]
+                            let existingObject = existingObjects[0]
                             XCTAssertEqual(existingObject, object)
                         }
                     }
@@ -799,7 +795,7 @@ class ImportTests: BaseTestDataTestCase {
                             sourceArray: sourceArray
                         )
                         XCTAssertEqual(objects.count, 1)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                         
                         let object = objects[0]
                         let dictionary = sourceArray[1]
@@ -864,10 +860,10 @@ class ImportTests: BaseTestDataTestCase {
                         catch _ as TestIDError {
                             
                             errorExpectation.fulfill()
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 5)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 5)
                             
-                            XCTAssertNil(transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106)))
-                            XCTAssertNil(transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 107)))
+                            XCTAssertNil(try transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106)))
+                            XCTAssertNil(try transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 107)))
                         }
                         transaction.unsafeContext().reset()
                         self.checkExpectationsImmediately()
@@ -910,7 +906,7 @@ class ImportTests: BaseTestDataTestCase {
                             
                             errorExpectation.fulfill()
                             
-                            let object = transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106))
+                            let object = try transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 106))
                             XCTAssertNotNil(object)
                             XCTAssertEqual(object?.testEntityID, NSNumber(value: 106))
                             XCTAssertNil(object?.testBoolean)
@@ -951,9 +947,9 @@ class ImportTests: BaseTestDataTestCase {
                         catch _ as TestUpdateError {
                             
                             errorExpectation.fulfill()
-                            XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 5)
+                            XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 5)
                             
-                            let object = transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
+                            let object = try transaction.fetchOne(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
                             XCTAssertNotNil(object)
                             XCTAssertEqual(object?.testEntityID, NSNumber(value: 105))
                             XCTAssertEqual(object?.testBoolean, NSNumber(value: true))
@@ -963,11 +959,10 @@ class ImportTests: BaseTestDataTestCase {
                             XCTAssertEqual(object?.testData, ("nil:TestEntity1:5" as NSString).data(using: String.Encoding.utf8.rawValue)!)
                             XCTAssertEqual(object?.testDate, self.dateFormatter.date(from: "2000-01-05T00:00:00Z")!)
                             
-                            let existingObjects = transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
-                            XCTAssertNotNil(existingObjects)
-                            XCTAssertEqual(existingObjects?.count, 1)
+                            let existingObjects = try transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
+                            XCTAssertEqual(existingObjects.count, 1)
                             
-                            let existingObject = existingObjects?[0]
+                            let existingObject = existingObjects[0]
                             XCTAssertEqual(existingObject, object)
                         }
                         transaction.context.reset()
@@ -1018,7 +1013,7 @@ class ImportTests: BaseTestDataTestCase {
                             sourceArray: sourceArray
                         )
                         XCTAssertEqual(objects.count, sourceArray.count)
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 6)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 6)
                         for i in 0 ..< sourceArray.count {
                             
                             let object = objects[i]
@@ -1032,11 +1027,10 @@ class ImportTests: BaseTestDataTestCase {
                             XCTAssertEqual(object.testData, dictionary[(#keyPath(TestEntity1.testData))] as? Data)
                             XCTAssertEqual(object.testDate, dictionary[(#keyPath(TestEntity1.testDate))] as? Date)
                         }
-                        let existingObjects = transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
-                        XCTAssertNotNil(existingObjects)
-                        XCTAssertEqual(existingObjects?.count, 1)
+                        let existingObjects = try transaction.fetchAll(From<TestEntity1>(), Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 105))
+                        XCTAssertEqual(existingObjects.count, 1)
                         
-                        let existingObject = existingObjects?[0]
+                        let existingObject = existingObjects[0]
                         XCTAssertEqual(existingObject, objects[0])
                     }
                 )

CoreStoreTests/ListObserverTests.swift

@@ -76,7 +76,7 @@ class ListObserverTests: BaseTestDataTestCase {
                     XCTAssertEqual(
                         ((note.userInfo as NSDictionary?) ?? [:]),
                         [
-                            "sectionInfo": monitor.sectionInfoAtIndex(0),
+                            "sectionInfo": monitor.sectionInfo(at: 0),
                             "sectionIndex": 0
                         ] as NSDictionary
                     )
@@ -178,9 +178,9 @@ class ListObserverTests: BaseTestDataTestCase {
             XCTAssertTrue(monitor.hasSections())
             XCTAssertEqual(monitor.numberOfSections(), 2)
             XCTAssertTrue(monitor.hasObjects())
-            XCTAssertTrue(monitor.hasObjectsInSection(0))
-            XCTAssertEqual(monitor.numberOfObjectsInSection(0), 2)
-            XCTAssertEqual(monitor.numberOfObjectsInSection(1), 3)
+            XCTAssertTrue(monitor.hasObjects(in: 0))
+            XCTAssertEqual(monitor.numberOfObjects(in: 0), 2)
+            XCTAssertEqual(monitor.numberOfObjects(in: 1), 3)
             
             var events = 0
             
@@ -268,7 +268,7 @@ class ListObserverTests: BaseTestDataTestCase {
             stack.perform(
                 asynchronous: { (transaction) -> Bool in
                     
-                    if let object = transaction.fetchOne(
+                    if let object = try transaction.fetchOne(
                         From<TestEntity1>(),
                         Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 101)) {
                         
@@ -282,7 +282,7 @@ class ListObserverTests: BaseTestDataTestCase {
                         
                         XCTFail()
                     }
-                    if let object = transaction.fetchOne(
+                    if let object = try transaction.fetchOne(
                         From<TestEntity1>(),
                         Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 102)) {
                         
@@ -394,7 +394,7 @@ class ListObserverTests: BaseTestDataTestCase {
             stack.perform(
                 asynchronous: { (transaction) -> Bool in
                     
-                    if let object = transaction.fetchOne(
+                    if let object = try transaction.fetchOne(
                         From<TestEntity1>(),
                         Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 102)) {
                         
@@ -526,7 +526,7 @@ class ListObserverTests: BaseTestDataTestCase {
             stack.perform(
                 asynchronous: { (transaction) -> Bool in
                     
-                    let count = transaction.deleteAll(
+                    let count = try transaction.deleteAll(
                         From<TestEntity1>(),
                         Where<TestEntity1>(#keyPath(TestEntity1.testBoolean), isEqualTo: false)
                     )

CoreStoreTests/ObjectObserverTests.swift

@@ -41,7 +41,7 @@ class ObjectObserverTests: BaseTestDataTestCase {
             
             self.prepareTestDataForStack(stack)
             
-            guard let object = stack.fetchOne(
+            guard let object = try stack.fetchOne(
                 From<TestEntity1>(),
                 Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 101)) else {
                     
@@ -138,7 +138,7 @@ class ObjectObserverTests: BaseTestDataTestCase {
             
             self.prepareTestDataForStack(stack)
             
-            guard let object = stack.fetchOne(
+            guard let object = try stack.fetchOne(
                 From<TestEntity1>(),
                 Where<TestEntity1>(#keyPath(TestEntity1.testEntityID), isEqualTo: 101)) else {
                     

CoreStoreTests/QueryTests.swift

@@ -47,7 +47,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(#keyPath(TestEntity1.testBoolean)),
                     queryClauses
@@ -57,7 +57,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -67,7 +67,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -77,7 +77,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -87,7 +87,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -97,7 +97,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -107,7 +107,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -117,7 +117,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -127,7 +127,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(#keyPath(TestEntity1.testNumber)),
                     queryClauses
@@ -137,7 +137,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(#keyPath(TestEntity1.testDecimal)),
                     queryClauses
@@ -147,7 +147,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(#keyPath(TestEntity1.testString)),
                     queryClauses
@@ -157,7 +157,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(#keyPath(TestEntity1.testString)),
                     queryClauses
@@ -167,7 +167,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(#keyPath(TestEntity1.testData)),
                     queryClauses
@@ -177,7 +177,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(#keyPath(TestEntity1.testData)),
                     queryClauses
@@ -187,7 +187,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(#keyPath(TestEntity1.testDate)),
                     queryClauses
@@ -197,7 +197,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(#keyPath(TestEntity1.testDate)),
                     queryClauses
@@ -207,7 +207,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(#keyPath(TestEntity1.testDate)),
                     queryClauses
@@ -232,7 +232,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(.average(#keyPath(TestEntity1.testBoolean))),
                     queryClauses
@@ -242,7 +242,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -252,7 +252,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -262,7 +262,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -272,7 +272,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -282,7 +282,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -292,7 +292,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -302,7 +302,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -312,7 +312,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(.average(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -322,7 +322,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(.average(#keyPath(TestEntity1.testDecimal))),
                     queryClauses
@@ -332,7 +332,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(.average(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -341,7 +341,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(.average(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -350,7 +350,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(.average(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -359,7 +359,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(.average(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -368,7 +368,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(.average(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -377,7 +377,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(.average(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -386,7 +386,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(#keyPath(TestEntity1.testEntityID)),
                     queryClauses
@@ -410,7 +410,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(.count(#keyPath(TestEntity1.testBoolean))),
                     queryClauses
@@ -420,7 +420,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -430,7 +430,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -440,7 +440,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -450,7 +450,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -460,7 +460,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -470,7 +470,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -480,7 +480,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -490,7 +490,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(.count(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -500,7 +500,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(.count(#keyPath(TestEntity1.testDecimal))),
                     queryClauses
@@ -509,7 +509,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(.count(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -518,7 +518,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(.count(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -527,7 +527,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(.count(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -536,7 +536,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(.count(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -545,7 +545,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(.count(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -554,7 +554,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(.count(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -563,7 +563,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(.count(#keyPath(TestEntity1.testEntityID))),
                     queryClauses
@@ -587,7 +587,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(.maximum(#keyPath(TestEntity1.testBoolean))),
                     queryClauses
@@ -597,7 +597,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -607,7 +607,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -617,7 +617,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -627,7 +627,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -637,7 +637,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -647,7 +647,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -657,7 +657,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -667,7 +667,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(.maximum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -677,7 +677,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(.maximum(#keyPath(TestEntity1.testDecimal))),
                     queryClauses
@@ -687,7 +687,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(.maximum(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -697,7 +697,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(.maximum(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -707,7 +707,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(.maximum(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -717,7 +717,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(.maximum(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -727,7 +727,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(.maximum(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -737,7 +737,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(.maximum(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -747,7 +747,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(.maximum(#keyPath(TestEntity1.testEntityID))),
                     queryClauses
@@ -771,7 +771,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(.minimum(#keyPath(TestEntity1.testBoolean))),
                     queryClauses
@@ -781,7 +781,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -791,7 +791,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -801,7 +801,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -811,7 +811,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -821,7 +821,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -831,7 +831,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -841,7 +841,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -851,7 +851,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(.minimum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -861,7 +861,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(.minimum(#keyPath(TestEntity1.testDecimal))),
                     queryClauses
@@ -871,7 +871,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(.minimum(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -881,7 +881,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(.minimum(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -891,7 +891,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(.minimum(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -901,7 +901,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(.minimum(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -911,7 +911,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(.minimum(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -921,7 +921,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(.minimum(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -931,7 +931,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(.minimum(#keyPath(TestEntity1.testEntityID))),
                     queryClauses
@@ -955,7 +955,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(.sum(#keyPath(TestEntity1.testBoolean))),
                     queryClauses
@@ -965,7 +965,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -975,7 +975,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -985,7 +985,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -995,7 +995,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -1005,7 +1005,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -1015,7 +1015,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -1025,7 +1025,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -1035,7 +1035,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(.sum(#keyPath(TestEntity1.testNumber))),
                     queryClauses
@@ -1045,7 +1045,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(.sum(#keyPath(TestEntity1.testDecimal))),
                     queryClauses
@@ -1055,7 +1055,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(.sum(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -1064,7 +1064,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(.sum(#keyPath(TestEntity1.testString))),
                     queryClauses
@@ -1073,7 +1073,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(.sum(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -1082,7 +1082,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(.sum(#keyPath(TestEntity1.testData))),
                     queryClauses
@@ -1091,7 +1091,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(.sum(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -1100,7 +1100,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(.sum(#keyPath(TestEntity1.testDate))),
                     queryClauses
@@ -1109,7 +1109,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(.sum(#keyPath(TestEntity1.testEntityID))),
                     queryClauses
@@ -1133,7 +1133,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Bool>(.objectID()),
                     queryClauses
@@ -1142,7 +1142,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int8>(.objectID()),
                     queryClauses
@@ -1151,7 +1151,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int16>(.objectID()),
                     queryClauses
@@ -1160,7 +1160,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int32>(.objectID()),
                     queryClauses
@@ -1169,7 +1169,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int64>(.objectID()),
                     queryClauses
@@ -1178,7 +1178,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Int>(.objectID()),
                     queryClauses
@@ -1187,7 +1187,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Double>(.objectID()),
                     queryClauses
@@ -1196,7 +1196,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Float>(.objectID()),
                     queryClauses
@@ -1205,7 +1205,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSNumber>(.objectID()),
                     queryClauses
@@ -1214,7 +1214,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDecimalNumber>(.objectID()),
                     queryClauses
@@ -1223,7 +1223,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, String>(.objectID()),
                     queryClauses
@@ -1232,7 +1232,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSString>(.objectID()),
                     queryClauses
@@ -1241,7 +1241,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Data>(.objectID()),
                     queryClauses
@@ -1250,7 +1250,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSData>(.objectID()),
                     queryClauses
@@ -1259,7 +1259,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, Date>(.objectID()),
                     queryClauses
@@ -1268,7 +1268,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSDate>(.objectID()),
                     queryClauses
@@ -1277,7 +1277,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let value = stack.queryValue(
+                let value = try stack.queryValue(
                     from,
                     Select<TestEntity1, NSManagedObjectID>(.objectID()),
                     queryClauses
@@ -1302,7 +1302,7 @@ class QueryTests: BaseTestDataTestCase {
             ]
             do {
                 
-                let values = stack.queryAttributes(
+                let values = try stack.queryAttributes(
                     from,
                     Select<TestEntity1, NSDictionary>(
                         #keyPath(TestEntity1.testBoolean),
@@ -1353,7 +1353,7 @@ class QueryTests: BaseTestDataTestCase {
             let queryClauses: [QueryClause] = []
             do {
                 
-                let values = stack.queryAttributes(
+                let values = try stack.queryAttributes(
                     from,
                     Select<TestEntity1, NSDictionary>(
                         .sum(#keyPath(TestEntity1.testBoolean)),
@@ -1380,7 +1380,7 @@ class QueryTests: BaseTestDataTestCase {
             }
             do {
                 
-                let values = stack.queryAttributes(
+                let values = try stack.queryAttributes(
                     from,
                     Select(
                         .sum(#keyPath(TestEntity1.testBoolean), as: "testSum"),

CoreStoreTests/TransactionTests.swift

@@ -69,9 +69,9 @@ final class TransactionTests: BaseTestCase {
                 self.checkExpectationsImmediately()
                 XCTAssertTrue(hasChanges)
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
                 
-                let object = stack.fetchOne(From<TestEntity1>())
+                let object = try stack.fetchOne(From<TestEntity1>())
                 XCTAssertNotNil(object)
                 XCTAssertEqual(object?.fetchSource()?.unsafeContext(), stack.mainContext)
                 XCTAssertEqual(object?.querySource()?.unsafeContext(), stack.mainContext)
@@ -84,14 +84,14 @@ final class TransactionTests: BaseTestCase {
             do {
                 
                 let updateExpectation = self.expectation(description: "update")
-                let hasChanges: Bool = try! stack.perform(
+                let hasChanges: Bool = try stack.perform(
                     synchronous: { (transaction) in
                         
                         defer {
                             
                             updateExpectation.fulfill()
                         }
-                        guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                             // TODO: convert fetch methods to throwing methods
                             XCTFail() 
                             try transaction.cancel()
@@ -107,9 +107,9 @@ final class TransactionTests: BaseTestCase {
                 self.checkExpectationsImmediately()
                 XCTAssertTrue(hasChanges)
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
                 
-                let object = stack.fetchOne(From<TestEntity1>())
+                let object = try stack.fetchOne(From<TestEntity1>())
                 XCTAssertNotNil(object)
                 XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                 XCTAssertEqual(object?.testString, "string1_edit")
@@ -128,7 +128,7 @@ final class TransactionTests: BaseTestCase {
                                 
                                 deleteExpectation.fulfill()
                             }
-                            let object = transaction.fetchOne(From<TestEntity1>())
+                            let object = try transaction.fetchOne(From<TestEntity1>())
                             transaction.delete(object)
                             return transaction.hasChanges
                         }
@@ -141,9 +141,9 @@ final class TransactionTests: BaseTestCase {
                 }
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 0)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 0)
                 
-                let object = stack.fetchOne(From<TestEntity1>())
+                let object = try stack.fetchOne(From<TestEntity1>())
                 XCTAssertNil(object)
             }
         }
@@ -184,10 +184,10 @@ final class TransactionTests: BaseTestCase {
                 }
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 1)
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 1)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
                 
-                let object = stack.fetchOne(From<TestEntity1>("Config1"))
+                let object = try stack.fetchOne(From<TestEntity1>("Config1"))
                 XCTAssertNotNil(object)
                 XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                 XCTAssertEqual(object?.testString, "string1")
@@ -206,7 +206,7 @@ final class TransactionTests: BaseTestCase {
                                 
                                 updateExpectation.fulfill()
                             }
-                            guard let object = transaction.fetchOne(From<TestEntity1>("Config1")) else {
+                            guard let object = try transaction.fetchOne(From<TestEntity1>("Config1")) else {
                                 
                                 XCTFail()
                                 try transaction.cancel()
@@ -226,10 +226,10 @@ final class TransactionTests: BaseTestCase {
                 }
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 1)
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 1)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
                 
-                let object = stack.fetchOne(From<TestEntity1>("Config1"))
+                let object = try stack.fetchOne(From<TestEntity1>("Config1"))
                 XCTAssertNotNil(object)
                 XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                 XCTAssertEqual(object?.testString, "string1_edit")
@@ -248,7 +248,7 @@ final class TransactionTests: BaseTestCase {
                                 
                                 deleteExpectation.fulfill()
                             }
-                            let object = transaction.fetchOne(From<TestEntity1>("Config1"))
+                            let object = try transaction.fetchOne(From<TestEntity1>("Config1"))
                             transaction.delete(object)
                             
                             return transaction.hasChanges
@@ -262,8 +262,8 @@ final class TransactionTests: BaseTestCase {
                 }
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 0)
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 0)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
             }
         }
     }
@@ -294,9 +294,9 @@ final class TransactionTests: BaseTestCase {
                 )
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 0)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 0)
                 
-                let object = stack.fetchOne(From<TestEntity1>())
+                let object = try stack.fetchOne(From<TestEntity1>())
                 XCTAssertNil(object)
             }
             let testDate = Date()
@@ -329,7 +329,7 @@ final class TransactionTests: BaseTestCase {
                             
                             updateDiscardExpectation.fulfill()
                         }
-                        guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                             
                             XCTFail()
                             try transaction.cancel()
@@ -343,9 +343,9 @@ final class TransactionTests: BaseTestCase {
                 )
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
                 
-                let object = stack.fetchOne(From<TestEntity1>())
+                let object = try stack.fetchOne(From<TestEntity1>())
                 XCTAssertNotNil(object)
                 XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                 XCTAssertEqual(object?.testString, "string1")
@@ -362,7 +362,7 @@ final class TransactionTests: BaseTestCase {
                             
                             deleteDiscardExpectation.fulfill()
                         }
-                        guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                             
                             XCTFail()
                             try transaction.cancel()
@@ -374,9 +374,9 @@ final class TransactionTests: BaseTestCase {
                 )
                 self.checkExpectationsImmediately()
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
                 
-                let object = stack.fetchOne(From<TestEntity1>())
+                let object = try stack.fetchOne(From<TestEntity1>())
                 XCTAssertNotNil(object)
                 XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                 XCTAssertEqual(object?.testString, "string1")
@@ -520,19 +520,26 @@ final class TransactionTests: BaseTestCase {
                     success: { (hasChanges) in
                         
                         XCTAssertTrue(hasChanges)
-                        
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
-                        
-                        let object = stack.fetchOne(From<TestEntity1>())
-                        XCTAssertNotNil(object)
-                        XCTAssertEqual(object?.fetchSource()?.unsafeContext(), stack.mainContext)
-                        XCTAssertEqual(object?.querySource()?.unsafeContext(), stack.mainContext)
-                        
-                        XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
-                        XCTAssertEqual(object?.testString, "string1")
-                        XCTAssertEqual(object?.testNumber, 100)
-                        XCTAssertEqual(object?.testDate, testDate)
-                        createExpectation.fulfill()
+
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
+
+                            let object = try stack.fetchOne(From<TestEntity1>())
+                            XCTAssertNotNil(object)
+                            XCTAssertEqual(object?.fetchSource()?.unsafeContext(), stack.mainContext)
+                            XCTAssertEqual(object?.querySource()?.unsafeContext(), stack.mainContext)
+
+                            XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
+                            XCTAssertEqual(object?.testString, "string1")
+                            XCTAssertEqual(object?.testNumber, 100)
+                            XCTAssertEqual(object?.testDate, testDate)
+                            createExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     },
                     failure: { _ in
                         
@@ -546,7 +553,7 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Bool in
                         
-                        guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                             
                             XCTFail()
                             try transaction.cancel()
@@ -560,16 +567,23 @@ final class TransactionTests: BaseTestCase {
                     success: { (hasChanges) in
                         
                         XCTAssertTrue(hasChanges)
-                        
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
-                        
-                        let object = stack.fetchOne(From<TestEntity1>())
-                        XCTAssertNotNil(object)
-                        XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
-                        XCTAssertEqual(object?.testString, "string1_edit")
-                        XCTAssertEqual(object?.testNumber, 200)
-                        XCTAssertEqual(object?.testDate, Date.distantFuture)
-                        updateExpectation.fulfill()
+
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
+
+                            let object = try stack.fetchOne(From<TestEntity1>())
+                            XCTAssertNotNil(object)
+                            XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
+                            XCTAssertEqual(object?.testString, "string1_edit")
+                            XCTAssertEqual(object?.testNumber, 200)
+                            XCTAssertEqual(object?.testDate, Date.distantFuture)
+                            updateExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     },
                     failure: { _ in
                         
@@ -583,7 +597,7 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Bool in
                         
-                        let object = transaction.fetchOne(From<TestEntity1>())
+                        let object = try transaction.fetchOne(From<TestEntity1>())
                         transaction.delete(object)
                         
                         return transaction.hasChanges
@@ -591,12 +605,19 @@ final class TransactionTests: BaseTestCase {
                     success: { (hasChanges) in
                         
                         XCTAssertTrue(hasChanges)
-                        
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 0)
-                        
-                        let object = stack.fetchOne(From<TestEntity1>())
-                        XCTAssertNil(object)
-                        deleteExpectation.fulfill()
+
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 0)
+
+                            let object = try stack.fetchOne(From<TestEntity1>())
+                            XCTAssertNil(object)
+                            deleteExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     },
                     failure: { _ in
                         
@@ -631,17 +652,24 @@ final class TransactionTests: BaseTestCase {
                     success: { (hasChanges) in
                         
                         XCTAssertTrue(hasChanges)
-                        
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 1)
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
-                        
-                        let object = stack.fetchOne(From<TestEntity1>("Config1"))
-                        XCTAssertNotNil(object)
-                        XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
-                        XCTAssertEqual(object?.testString, "string1")
-                        XCTAssertEqual(object?.testNumber, 100)
-                        XCTAssertEqual(object?.testDate, testDate)
-                        createExpectation.fulfill()
+
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 1)
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
+
+                            let object = try stack.fetchOne(From<TestEntity1>("Config1"))
+                            XCTAssertNotNil(object)
+                            XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
+                            XCTAssertEqual(object?.testString, "string1")
+                            XCTAssertEqual(object?.testNumber, 100)
+                            XCTAssertEqual(object?.testDate, testDate)
+                            createExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     },
                     failure: { _ in
                         
@@ -655,7 +683,7 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Bool in
                         
-                        guard let object = transaction.fetchOne(From<TestEntity1>("Config1")) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>("Config1")) else {
                             
                             XCTFail()
                             try transaction.cancel()
@@ -669,17 +697,24 @@ final class TransactionTests: BaseTestCase {
                     success: { (hasChanges) in
                         
                         XCTAssertTrue(hasChanges)
-                        
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 1)
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
-                        
-                        let object = stack.fetchOne(From<TestEntity1>("Config1"))
-                        XCTAssertNotNil(object)
-                        XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
-                        XCTAssertEqual(object?.testString, "string1_edit")
-                        XCTAssertEqual(object?.testNumber, 200)
-                        XCTAssertEqual(object?.testDate, Date.distantFuture)
-                        updateExpectation.fulfill()
+
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 1)
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
+
+                            let object = try stack.fetchOne(From<TestEntity1>("Config1"))
+                            XCTAssertNotNil(object)
+                            XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
+                            XCTAssertEqual(object?.testString, "string1_edit")
+                            XCTAssertEqual(object?.testNumber, 200)
+                            XCTAssertEqual(object?.testDate, Date.distantFuture)
+                            updateExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     },
                     failure: { _ in
                         
@@ -693,7 +728,7 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Bool in
                         
-                        let object = transaction.fetchOne(From<TestEntity1>("Config1"))
+                        let object = try transaction.fetchOne(From<TestEntity1>("Config1"))
                         transaction.delete(object)
                         
                         return transaction.hasChanges
@@ -701,11 +736,18 @@ final class TransactionTests: BaseTestCase {
                     success: { (hasChanges) in
                         
                         XCTAssertTrue(hasChanges)
-                        
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 0)
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
-                        
-                        deleteExpectation.fulfill()
+
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 0)
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
+
+                            deleteExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     },
                     failure: { _ in
                         
@@ -754,8 +796,8 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Bool in
                         
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 0)
-                        XCTAssertNil(transaction.fetchOne(From<TestEntity1>()))
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 0)
+                        XCTAssertNil(try transaction.fetchOne(From<TestEntity1>()))
                         
                         let object = transaction.create(Into<TestEntity1>())
                         object.testEntityID = NSNumber(value: 1)
@@ -782,7 +824,7 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Void in
                         
-                        guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                             
                             XCTFail()
                             return
@@ -811,9 +853,9 @@ final class TransactionTests: BaseTestCase {
                 stack.perform(
                     asynchronous: { (transaction) -> Void in
                         
-                        XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
+                        XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
                         
-                        guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                        guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                             
                             XCTFail()
                             try transaction.cancel()
@@ -835,15 +877,22 @@ final class TransactionTests: BaseTestCase {
                     failure: { (error) in
                         
                         XCTAssertEqual(error, CoreStoreError.userCancelled)
-                        XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
-                        
-                        let object = stack.fetchOne(From<TestEntity1>())
-                        XCTAssertNotNil(object)
-                        XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
-                        XCTAssertEqual(object?.testString, "string1")
-                        XCTAssertEqual(object?.testNumber, 100)
-                        XCTAssertEqual(object?.testDate, testDate)
-                        deleteDiscardExpectation.fulfill()
+                        do {
+
+                            XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
+
+                            let object = try stack.fetchOne(From<TestEntity1>())
+                            XCTAssertNotNil(object)
+                            XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
+                            XCTAssertEqual(object?.testString, "string1")
+                            XCTAssertEqual(object?.testNumber, 100)
+                            XCTAssertEqual(object?.testDate, testDate)
+                            deleteDiscardExpectation.fulfill()
+                        }
+                        catch {
+
+                            XCTFail()
+                        }
                     }
                 )
             }
@@ -878,9 +927,9 @@ final class TransactionTests: BaseTestCase {
                     XCTAssertTrue(transaction.hasChanges)
                     try transaction.commitAndWait()
                     
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
                     
-                    let object = stack.fetchOne(From<TestEntity1>())
+                    let object = try stack.fetchOne(From<TestEntity1>())
                     XCTAssertNotNil(object)
                     XCTAssertEqual(object?.fetchSource()?.unsafeContext(), stack.mainContext)
                     XCTAssertEqual(object?.querySource()?.unsafeContext(), stack.mainContext)
@@ -897,7 +946,7 @@ final class TransactionTests: BaseTestCase {
             }
             do {
                 
-                guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                     
                     XCTFail()
                     return
@@ -911,9 +960,9 @@ final class TransactionTests: BaseTestCase {
                     XCTAssertTrue(transaction.hasChanges)
                     try transaction.commitAndWait()
                     
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
                     
-                    let object = stack.fetchOne(From<TestEntity1>())
+                    let object = try stack.fetchOne(From<TestEntity1>())
                     XCTAssertNotNil(object)
                     XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object?.testString, "string1_edit")
@@ -927,7 +976,7 @@ final class TransactionTests: BaseTestCase {
             }
             do {
                 
-                let object = transaction.fetchOne(From<TestEntity1>())
+                let object = try transaction.fetchOne(From<TestEntity1>())
                 transaction.delete(object)
                 
                 do {
@@ -935,8 +984,8 @@ final class TransactionTests: BaseTestCase {
                     XCTAssertTrue(transaction.hasChanges)
                     try transaction.commitAndWait()
                     
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 0)
-                    XCTAssertNil(stack.fetchOne(From<TestEntity1>()))
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 0)
+                    XCTAssertNil(try stack.fetchOne(From<TestEntity1>()))
                 }
                 catch {
                     
@@ -967,10 +1016,10 @@ final class TransactionTests: BaseTestCase {
                     XCTAssertTrue(transaction.hasChanges)
                     try transaction.commitAndWait()
                     
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 1)
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 1)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
                     
-                    let object = stack.fetchOne(From<TestEntity1>("Config1"))
+                    let object = try stack.fetchOne(From<TestEntity1>("Config1"))
                     XCTAssertNotNil(object)
                     XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object?.testString, "string1")
@@ -984,7 +1033,7 @@ final class TransactionTests: BaseTestCase {
             }
             do {
                 
-                guard let object = transaction.fetchOne(From<TestEntity1>("Config1")) else {
+                guard let object = try transaction.fetchOne(From<TestEntity1>("Config1")) else {
                     
                     XCTFail()
                     return
@@ -998,10 +1047,10 @@ final class TransactionTests: BaseTestCase {
                     XCTAssertTrue(transaction.hasChanges)
                     try transaction.commitAndWait()
                     
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 1)
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 1)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
                     
-                    let object = stack.fetchOne(From<TestEntity1>("Config1"))
+                    let object = try stack.fetchOne(From<TestEntity1>("Config1"))
                     XCTAssertNotNil(object)
                     XCTAssertEqual(object?.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object?.testString, "string1_edit")
@@ -1015,7 +1064,7 @@ final class TransactionTests: BaseTestCase {
             }
             do {
                 
-                let object = transaction.fetchOne(From<TestEntity1>("Config1"))
+                let object = try transaction.fetchOne(From<TestEntity1>("Config1"))
                 transaction.delete(object)
                 
                 do {
@@ -1023,8 +1072,8 @@ final class TransactionTests: BaseTestCase {
                     XCTAssertTrue(transaction.hasChanges)
                     try transaction.commitAndWait()
                     
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>("Config1")), 0)
-                    XCTAssertEqual(stack.fetchCount(From<TestEntity1>(nil)), 0)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>("Config1")), 0)
+                    XCTAssertEqual(try stack.fetchCount(From<TestEntity1>(nil)), 0)
                 }
                 catch {
                     
@@ -1050,11 +1099,11 @@ final class TransactionTests: BaseTestCase {
                 
                 transaction.rollback()
                 
-                XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 0)
-                XCTAssertNil(transaction.fetchOne(From<TestEntity1>()))
+                XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 0)
+                XCTAssertNil(try transaction.fetchOne(From<TestEntity1>()))
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 0)
-                XCTAssertNil(stack.fetchOne(From<TestEntity1>()))
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 0)
+                XCTAssertNil(try stack.fetchOne(From<TestEntity1>()))
             }
             
             let testDate = Date()
@@ -1079,7 +1128,7 @@ final class TransactionTests: BaseTestCase {
             
             do {
                 
-                guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                     
                     XCTFail()
                     return
@@ -1090,8 +1139,8 @@ final class TransactionTests: BaseTestCase {
                 
                 transaction.rollback()
                 
-                XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
-                if let object = transaction.fetchOne(From<TestEntity1>()) {
+                XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
+                if let object = try transaction.fetchOne(From<TestEntity1>()) {
                     
                     XCTAssertEqual(object.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object.testString, "string1")
@@ -1103,8 +1152,8 @@ final class TransactionTests: BaseTestCase {
                     XCTFail()
                 }
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
-                if let object = stack.fetchOne(From<TestEntity1>()) {
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
+                if let object = try stack.fetchOne(From<TestEntity1>()) {
                     
                     XCTAssertEqual(object.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object.testString, "string1")
@@ -1119,7 +1168,7 @@ final class TransactionTests: BaseTestCase {
             
             do {
                 
-                guard let object = transaction.fetchOne(From<TestEntity1>()) else {
+                guard let object = try transaction.fetchOne(From<TestEntity1>()) else {
                     
                     XCTFail()
                     return
@@ -1128,8 +1177,8 @@ final class TransactionTests: BaseTestCase {
                 
                 transaction.rollback()
                 
-                XCTAssertEqual(transaction.fetchCount(From<TestEntity1>()), 1)
-                if let object = transaction.fetchOne(From<TestEntity1>()) {
+                XCTAssertEqual(try transaction.fetchCount(From<TestEntity1>()), 1)
+                if let object = try transaction.fetchOne(From<TestEntity1>()) {
                     
                     XCTAssertEqual(object.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object.testString, "string1")
@@ -1141,8 +1190,8 @@ final class TransactionTests: BaseTestCase {
                     XCTFail()
                 }
                 
-                XCTAssertEqual(stack.fetchCount(From<TestEntity1>()), 1)
-                if let object = stack.fetchOne(From<TestEntity1>()) {
+                XCTAssertEqual(try stack.fetchCount(From<TestEntity1>()), 1)
+                if let object = try stack.fetchOne(From<TestEntity1>()) {
                     
                     XCTAssertEqual(object.testEntityID, NSNumber(value: 1))
                     XCTAssertEqual(object.testString, "string1")

Sources/BaseDataTransaction+Importing.swift

@@ -151,7 +151,7 @@ public extension BaseDataTransaction {
                     return nil
                 }
                 
-                if let object = self.fetchOne(From(entityType), Where<D>(uniqueIDKeyPath, isEqualTo: uniqueIDValue)) {
+                if let object = try self.fetchOne(From(entityType), Where<D>(uniqueIDKeyPath, isEqualTo: uniqueIDValue)) {
                     
                     guard entityType.shouldUpdate(from: source, in: self) else {
                         
@@ -215,7 +215,8 @@ public extension BaseDataTransaction {
                 importSourceByID = try autoreleasepool { try preProcess(importSourceByID) }
 
                 var existingObjectsByID = Dictionary<D.UniqueIDType, D>()
-                self.fetchAll(From(entityType), Where<D>(entityType.uniqueIDKeyPath, isMemberOf: sortedIDs))?
+                try self
+                    .fetchAll(From(entityType), Where<D>(entityType.uniqueIDKeyPath, isMemberOf: sortedIDs))
                     .forEach { existingObjectsByID[$0.uniqueIDValue] = $0 }
               
                 var processedObjectIDs = Set<D.UniqueIDType>()

Sources/BaseDataTransaction+Querying.swift

@@ -39,13 +39,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - returns: the number of `DynamicObject`s deleted
      */
     @discardableResult
-    public func deleteAll<D>(_ from: From<D>, _ deleteClauses: DeleteClause...) -> Int? {
+    public func deleteAll<D>(_ from: From<D>, _ deleteClauses: DeleteClause...) throws -> Int {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to delete from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.deleteAll(from, deleteClauses)
+        return try self.context.deleteAll(from, deleteClauses)
     }
     
     /**
@@ -56,13 +56,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - returns: the number of `DynamicObject`s deleted
      */
     @discardableResult
-    public func deleteAll<D>(_ from: From<D>, _ deleteClauses: [DeleteClause]) -> Int? {
+    public func deleteAll<D>(_ from: From<D>, _ deleteClauses: [DeleteClause]) throws -> Int {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to delete from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.deleteAll(from, deleteClauses)
+        return try self.context.deleteAll(from, deleteClauses)
     }
     
     /**
@@ -74,14 +74,14 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - returns: the number of `DynamicObject`s deleted
      */
     @discardableResult
-    public func deleteAll<B: FetchChainableBuilderType>(_ clauseChain: B) -> Int? {
+    public func deleteAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to delete from a \(cs_typeName(self)) outside its designated queue."
         )
         
-        return self.context.deleteAll(clauseChain.from, clauseChain.fetchClauses)
+        return try self.context.deleteAll(clauseChain.from, clauseChain.fetchClauses)
     }
     
     
@@ -297,13 +297,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> NSManagedObjectID? {
+    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchObjectID(from, fetchClauses)
+        return try self.context.fetchObjectID(from, fetchClauses)
     }
     
     /**
@@ -313,13 +313,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> NSManagedObjectID? {
+    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchObjectID(from, fetchClauses)
+        return try self.context.fetchObjectID(from, fetchClauses)
     }
     
     /**
@@ -334,13 +334,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
      */
-    public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) -> NSManagedObjectID? {
+    public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchObjectID(clauseChain)
+        return try self.context.fetchObjectID(clauseChain)
     }
     
     /**
@@ -350,13 +350,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchObjectIDs(from, fetchClauses)
+        return try self.context.fetchObjectIDs(from, fetchClauses)
     }
     
     /**
@@ -366,13 +366,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchObjectIDs(from, fetchClauses)
+        return try self.context.fetchObjectIDs(from, fetchClauses)
     }
     
     /**
@@ -387,13 +387,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchObjectIDs(clauseChain)
+        return try self.context.fetchObjectIDs(clauseChain)
     }
     
     
@@ -409,13 +409,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) -> U? {
+    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.queryValue(from, selectClause, queryClauses)
+        return try self.context.queryValue(from, selectClause, queryClauses)
     }
     
     /**
@@ -428,13 +428,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) -> U? {
+    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.queryValue(from, selectClause, queryClauses)
+        return try self.context.queryValue(from, selectClause, queryClauses)
     }
     
     /**
@@ -451,13 +451,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    public func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) -> B.ResultType? where B.ResultType: QueryableAttributeType {
+    public func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.queryValue(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
+        return try self.context.queryValue(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
     }
     
     /**
@@ -470,13 +470,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) -> [[String: Any]]? {
+    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.queryAttributes(from, selectClause, queryClauses)
+        return try self.context.queryAttributes(from, selectClause, queryClauses)
     }
     
     /**
@@ -489,13 +489,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) -> [[String: Any]]? {
+    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.queryAttributes(from, selectClause, queryClauses)
+        return try self.context.queryAttributes(from, selectClause, queryClauses)
     }
     
     /**
@@ -521,13 +521,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    public func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) -> [[String: Any]]? where B.ResultType == NSDictionary {
+    public func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.queryAttributes(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
+        return try self.context.queryAttributes(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
     }
     
     

Sources/CSBaseDataTransaction+Querying.swift

@@ -93,7 +93,8 @@ public extension CSBaseDataTransaction {
             self.swiftTransaction.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.swiftTransaction.context.fetchOne(from, fetchClauses)
+        return (try? self.swiftTransaction.context.fetchOne(from, fetchClauses))?
+            .flatMap({ $0 })
     }
     
     /**
@@ -110,7 +111,8 @@ public extension CSBaseDataTransaction {
             self.swiftTransaction.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.swiftTransaction.context.fetchAll(from, fetchClauses)
+        return (try? self.swiftTransaction.context.fetchAll(from, fetchClauses))
+            .flatMap({ $0 })
     }
     
     /**
@@ -127,9 +129,8 @@ public extension CSBaseDataTransaction {
             self.swiftTransaction.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.swiftTransaction.context
-            .fetchCount(from, fetchClauses)
-            .flatMap { NSNumber(value: $0) }
+        return (try? self.swiftTransaction.context.fetchCount(from, fetchClauses))
+            .flatMap({ NSNumber(value: $0) })
     }
     
     /**
@@ -146,7 +147,8 @@ public extension CSBaseDataTransaction {
             self.swiftTransaction.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.swiftTransaction.context.fetchObjectID(from, fetchClauses)
+        return (try? self.swiftTransaction.context.fetchObjectID(from, fetchClauses))
+            .flatMap({ $0 })
     }
     
     /**
@@ -166,7 +168,8 @@ public extension CSBaseDataTransaction {
             self.swiftTransaction.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.swiftTransaction.context.queryValue(from, selectClause, queryClauses)
+        return (try? self.swiftTransaction.context.queryValue(from, selectClause, queryClauses))
+            .flatMap({ $0 })
     }
     
     /**
@@ -186,6 +189,7 @@ public extension CSBaseDataTransaction {
             self.swiftTransaction.isRunningInAllowedQueue(),
             "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.swiftTransaction.context.queryAttributes(from, selectClause, queryClauses)
+        return (try? self.swiftTransaction.context.queryAttributes(from, selectClause, queryClauses))
+            .flatMap({ $0 })
     }
 }

Sources/CSDataStack+Querying.swift

@@ -93,7 +93,8 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext.fetchOne(from, fetchClauses)
+        return (try? self.bridgeToSwift.mainContext.fetchOne(from, fetchClauses))?
+            .flatMap({ $0 })
     }
     
     /**
@@ -110,7 +111,8 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext.fetchAll(from, fetchClauses)
+        return (try? self.bridgeToSwift.mainContext.fetchAll(from, fetchClauses))
+            .flatMap({ $0 })
     }
     
     /**
@@ -127,9 +129,8 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext
-            .fetchCount(from, fetchClauses)
-            .flatMap { NSNumber(value: $0) }
+        return (try? self.bridgeToSwift.mainContext.fetchCount(from, fetchClauses))
+            .flatMap({ NSNumber(value: $0) })
     }
     
     /**
@@ -146,7 +147,8 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext.fetchObjectID(from, fetchClauses)
+        return (try? self.bridgeToSwift.mainContext.fetchObjectID(from, fetchClauses))?
+            .flatMap({ $0 })
     }
     
     /**
@@ -163,7 +165,8 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext.fetchObjectIDs(from, fetchClauses)
+        return (try? self.bridgeToSwift.mainContext.fetchObjectIDs(from, fetchClauses))
+            .flatMap({ $0 })
     }
     
     /**
@@ -183,7 +186,8 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext.queryValue(from, selectClause, queryClauses)
+        return (try? self.bridgeToSwift.mainContext.queryValue(from, selectClause, queryClauses))
+            .flatMap({ $0 })
     }
     
     /**
@@ -203,6 +207,7 @@ public extension CSDataStack {
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.bridgeToSwift.mainContext.queryAttributes(from, selectClause, queryClauses)
+        return (try? self.bridgeToSwift.mainContext.queryAttributes(from, selectClause, queryClauses))
+            .flatMap({ $0 })
     }
 }

Sources/CoreStore+CustomDebugStringConvertible.swift

@@ -152,6 +152,10 @@ extension CoreStoreError: CustomDebugStringConvertible, CoreStoreDebugStringConv
             
         case .userCancelled:
             firstLine = ".userCancelled"
+
+        case .persistentStoreNotFound(let entity):
+            firstLine = ".persistentStoreNotFound"
+            info.append(("entity", entity))
         }
         
         return createFormattedString(

Sources/CoreStore+Querying.swift

@@ -205,9 +205,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    public static func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> NSManagedObjectID? {
+    public static func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
-        return self.defaultStack.fetchObjectID(from, fetchClauses)
+        return try self.defaultStack.fetchObjectID(from, fetchClauses)
     }
     
     /**
@@ -217,9 +217,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    public static func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> NSManagedObjectID? {
+    public static func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
-        return self.defaultStack.fetchObjectID(from, fetchClauses)
+        return try self.defaultStack.fetchObjectID(from, fetchClauses)
     }
     
     /**
@@ -234,9 +234,9 @@ public extension CoreStore {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
      */
-    public static func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) -> NSManagedObjectID? {
+    public static func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
-        return self.defaultStack.fetchObjectID(clauseChain)
+        return try self.defaultStack.fetchObjectID(clauseChain)
     }
     
     /**
@@ -246,9 +246,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public static func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [NSManagedObjectID]? {
+    public static func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
-        return self.defaultStack.fetchObjectIDs(from, fetchClauses)
+        return try self.defaultStack.fetchObjectIDs(from, fetchClauses)
     }
     
     /**
@@ -258,9 +258,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public static func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [NSManagedObjectID]? {
+    public static func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
-        return self.defaultStack.fetchObjectIDs(from, fetchClauses)
+        return try self.defaultStack.fetchObjectIDs(from, fetchClauses)
     }
     
     /**
@@ -275,9 +275,9 @@ public extension CoreStore {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    public static func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) -> [NSManagedObjectID]? {
+    public static func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
-        return self.defaultStack.fetchObjectIDs(clauseChain)
+        return try self.defaultStack.fetchObjectIDs(clauseChain)
     }
     
     /**
@@ -290,9 +290,9 @@ public extension CoreStore {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public static func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) -> U? {
+    public static func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
-        return self.defaultStack.queryValue(from, selectClause, queryClauses)
+        return try self.defaultStack.queryValue(from, selectClause, queryClauses)
     }
     
     /**
@@ -305,9 +305,9 @@ public extension CoreStore {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public static func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) -> U? {
+    public static func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
-        return self.defaultStack.queryValue(from, selectClause, queryClauses)
+        return try self.defaultStack.queryValue(from, selectClause, queryClauses)
     }
     
     /**
@@ -324,9 +324,9 @@ public extension CoreStore {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    public static func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) -> B.ResultType? where B.ResultType: QueryableAttributeType {
+    public static func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
         
-        return self.defaultStack.queryValue(clauseChain)
+        return try self.defaultStack.queryValue(clauseChain)
     }
     
     /**
@@ -339,9 +339,9 @@ public extension CoreStore {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public static func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) -> [[String: Any]]? {
+    public static func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
-        return self.defaultStack.queryAttributes(from, selectClause, queryClauses)
+        return try self.defaultStack.queryAttributes(from, selectClause, queryClauses)
     }
     
     /**
@@ -354,9 +354,9 @@ public extension CoreStore {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public static func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) -> [[String: Any]]? {
+    public static func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
-        return self.defaultStack.queryAttributes(from, selectClause, queryClauses)
+        return try self.defaultStack.queryAttributes(from, selectClause, queryClauses)
     }
     
     /**
@@ -382,8 +382,8 @@ public extension CoreStore {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    public static func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) -> [[String: Any]]? where B.ResultType == NSDictionary {
+    public static func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
         
-        return self.defaultStack.queryAttributes(clauseChain)
+        return try self.defaultStack.queryAttributes(clauseChain)
     }
 }

Sources/CoreStoreFetchedResultsController.swift

@@ -49,7 +49,7 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
     @nonobjc
     internal init<D>(context: NSManagedObjectContext, fetchRequest: NSFetchRequest<NSManagedObject>, from: From<D>, sectionBy: SectionBy<D>? = nil, applyFetchClauses: @escaping (_ fetchRequest: NSFetchRequest<NSManagedObject>) -> Void) {
         
-        _ = from.applyToFetchRequest(
+        _ = try? from.applyToFetchRequest(
             fetchRequest,
             context: context,
             applyAffectedStores: false
@@ -58,7 +58,7 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
         
         self.reapplyAffectedStores = { fetchRequest, context in
             
-            return try rom.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
+            try from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
         }
         
         super.init(
@@ -91,5 +91,5 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
     // MARK: Private
     
     @nonobjc
-    private let reapplyAffectedStores: (_ fetchRequest: NSFetchRequest<NSManagedObject>, _ context: NSManagedObjectContext) throws -> Bool
+    private let reapplyAffectedStores: (_ fetchRequest: NSFetchRequest<NSManagedObject>, _ context: NSManagedObjectContext) throws -> Void
 }

Sources/DataStack+Querying.swift

@@ -243,13 +243,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> NSManagedObjectID? {
+    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchObjectID(from, fetchClauses)
+        return try self.mainContext.fetchObjectID(from, fetchClauses)
     }
     
     /**
@@ -259,13 +259,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> NSManagedObjectID? {
+    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchObjectID(from, fetchClauses)
+        return try self.mainContext.fetchObjectID(from, fetchClauses)
     }
     
     /**
@@ -280,13 +280,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
      */
-    public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) -> NSManagedObjectID? {
+    public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchObjectID(clauseChain)
+        return try self.mainContext.fetchObjectID(clauseChain)
     }
     
     /**
@@ -296,13 +296,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchObjectIDs(from, fetchClauses)
+        return try self.mainContext.fetchObjectIDs(from, fetchClauses)
     }
     
     /**
@@ -312,13 +312,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchObjectIDs(from, fetchClauses)
+        return try self.mainContext.fetchObjectIDs(from, fetchClauses)
     }
     
     /**
@@ -333,13 +333,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchObjectIDs(clauseChain)
+        return try self.mainContext.fetchObjectIDs(clauseChain)
     }
     
     
@@ -355,13 +355,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) -> U? {
+    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.queryValue(from, selectClause, queryClauses)
+        return try self.mainContext.queryValue(from, selectClause, queryClauses)
     }
     
     /**
@@ -374,13 +374,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) -> U? {
+    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.queryValue(from, selectClause, queryClauses)
+        return try self.mainContext.queryValue(from, selectClause, queryClauses)
     }
     
     /**
@@ -397,13 +397,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    public func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) -> B.ResultType? where B.ResultType: QueryableAttributeType {
+    public func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.queryValue(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
+        return try self.mainContext.queryValue(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
     }
     
     /**
@@ -416,13 +416,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) -> [[String: Any]]? {
+    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.queryAttributes(from, selectClause, queryClauses)
+        return try self.mainContext.queryAttributes(from, selectClause, queryClauses)
     }
     
     /**
@@ -435,13 +435,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) -> [[String: Any]]? {
+    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.queryAttributes(from, selectClause, queryClauses)
+        return try self.mainContext.queryAttributes(from, selectClause, queryClauses)
     }
     
     /**
@@ -467,13 +467,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    public func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) -> [[String: Any]]? where B.ResultType == NSDictionary {
+    public func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to query from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.queryAttributes(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
+        return try self.mainContext.queryAttributes(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
     }
     
     

Sources/FetchableSource.swift

@@ -169,7 +169,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> NSManagedObjectID?
+    func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID?
 
     /**
      Fetches the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -178,7 +178,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
      */
-    func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> NSManagedObjectID?
+    func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID?
     
     /**
      Fetches the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType` built from a chain of clauses.
@@ -192,7 +192,7 @@ public protocol FetchableSource: class {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
      */
-    func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) -> NSManagedObjectID?
+    func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID?
 
     /**
      Fetches the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -201,7 +201,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [NSManagedObjectID]?
+    func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID]
 
     /**
      Fetches the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -210,7 +210,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [NSManagedObjectID]?
+    func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID]
     
     /**
      Fetches the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
@@ -224,7 +224,7 @@ public protocol FetchableSource: class {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) -> [NSManagedObjectID]?
+    func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID]
     
     /**
      The internal `NSManagedObjectContext` managed by this `FetchableSource`. Using this context directly should typically be avoided, and is provided by CoreStore only for extremely specialized cases.

Sources/NSManagedObjectContext+ObjectiveC.swift

@@ -96,57 +96,45 @@ internal extension NSManagedObjectContext {
     }
     
     @nonobjc
-    internal func deleteAll(_ from: CSFrom, _ deleteClauses: [CSDeleteClause]) -> Int? {
+    internal func deleteAll(_ from: CSFrom, _ deleteClauses: [CSDeleteClause]) throws -> Int {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectResultType
         fetchRequest.returnsObjectsAsFaults = true
         fetchRequest.includesPropertyValues = false
         deleteClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.deleteAll(fetchRequest.dynamicCast())
+
+        return try self.deleteAll(fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    internal func queryValue(_ from: CSFrom, _ selectClause: CSSelect, _ queryClauses: [CSQueryClause]) -> Any? {
+    internal func queryValue(_ from: CSFrom, _ selectClause: CSSelect, _ queryClauses: [CSQueryClause]) throws -> Any? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         
         selectClause.applyToFetchRequest(fetchRequest)
         queryClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.queryValue(selectClause.selectTerms, fetchRequest: fetchRequest.dynamicCast())
+
+        return try self.queryValue(selectClause.selectTerms, fetchRequest: fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    internal func queryAttributes(_ from: CSFrom, _ selectClause: CSSelect, _ queryClauses: [CSQueryClause]) -> [[String: Any]]? {
+    internal func queryAttributes(_ from: CSFrom, _ selectClause: CSSelect, _ queryClauses: [CSQueryClause]) throws -> [[String: Any]] {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         
         selectClause.applyToFetchRequest(fetchRequest)
         queryClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.queryAttributes(fetchRequest.dynamicCast())
+
+        return try self.queryAttributes(fetchRequest.dynamicCast())
     }
 }

Sources/NSManagedObjectContext+Querying.swift

@@ -142,11 +142,11 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
         let entityClass = from.entityClass
-        return try self.fetchAll(fetchRequest.dynamicCast())?.map(entityClass.cs_fromRaw)
+        return try self.fetchAll(fetchRequest.dynamicCast()).map(entityClass.cs_fromRaw)
     }
     
     @nonobjc
-    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throw -> [B.ObjectType] {
+    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
         
         return try self.fetchAll(clauseChain.from, clauseChain.fetchClauses)
     }
@@ -174,42 +174,38 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
     }
     
     @nonobjc
-    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> NSManagedObjectID? {
+    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
-        return self.fetchObjectID(from, fetchClauses)
+        return try self.fetchObjectID(from, fetchClauses)
     }
     
     @nonobjc
-    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> NSManagedObjectID? {
+    public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 1
         fetchRequest.resultType = .managedObjectIDResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.fetchObjectID(fetchRequest.dynamicCast())
+
+        return try self.fetchObjectID(fetchRequest.dynamicCast())
     }
 
     @nonobjc
-    public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) -> NSManagedObjectID? {
+    public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
-        return self.fetchObjectID(clauseChain.from, clauseChain.fetchClauses)
+        return try self.fetchObjectID(clauseChain.from, clauseChain.fetchClauses)
     }
     
     @nonobjc
-    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
-        return self.fetchObjectIDs(from, fetchClauses)
+        return try self.fetchObjectIDs(from, fetchClauses)
     }
     
     @nonobjc
-    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
         let fetchRequest = CoreStoreFetchRequest()
         try from.applyToFetchRequest(fetchRequest, context: self)
@@ -217,22 +213,18 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectIDResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.fetchObjectIDs(fetchRequest.dynamicCast())
+
+        return try self.fetchObjectIDs(fetchRequest.dynamicCast())
     }
 
     @nonobjc
-    public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) -> [NSManagedObjectID]? {
+    public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
-        return self.fetchObjectIDs(clauseChain.from, clauseChain.fetchClauses)
+        return try self.fetchObjectIDs(clauseChain.from, clauseChain.fetchClauses)
     }
     
     @nonobjc
-    internal func fetchObjectIDs(_ fetchRequest: NSFetchRequest<NSManagedObjectID>) -> [NSManagedObjectID]? {
+    internal func fetchObjectIDs(_ fetchRequest: NSFetchRequest<NSManagedObjectID>) throws -> [NSManagedObjectID] {
         
         var fetchResults: [NSManagedObjectID]?
         var fetchError: Error?
@@ -247,77 +239,70 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
                 fetchError = error
             }
         }
-        if fetchResults == nil {
-            
-            CoreStore.log(
-                CoreStoreError(fetchError),
-                "Failed executing fetch request."
-            )
-            return nil
+        if let fetchResults = fetchResults {
+
+            return fetchResults
         }
-        return fetchResults
+        let coreStoreError = CoreStoreError(fetchError)
+        CoreStore.log(
+            coreStoreError,
+            "Failed executing fetch request."
+        )
+        throw coreStoreError
     }
     
     
     // MARK: QueryableSource
     
     @nonobjc
-    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) -> U? {
+    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
-        return self.queryValue(from, selectClause, queryClauses)
+        return try self.queryValue(from, selectClause, queryClauses)
     }
     
     @nonobjc
-    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) -> U? {
+    public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         
         selectClause.applyToFetchRequest(fetchRequest)
         queryClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.queryValue(selectClause.selectTerms, fetchRequest: fetchRequest)
+
+        return try self.queryValue(selectClause.selectTerms, fetchRequest: fetchRequest)
     }
     
     @nonobjc
-    public func queryValue<B>(_ clauseChain: B) -> B.ResultType? where B: QueryChainableBuilderType, B.ResultType: QueryableAttributeType {
+    public func queryValue<B>(_ clauseChain: B) throws -> B.ResultType? where B: QueryChainableBuilderType, B.ResultType: QueryableAttributeType {
         
-        return self.queryValue(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
+        return try self.queryValue(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
     }
     
     @nonobjc
-    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) -> [[String: Any]]? {
+    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
-        return self.queryAttributes(from, selectClause, queryClauses)
+        return try self.queryAttributes(from, selectClause, queryClauses)
     }
     
     @nonobjc
-    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) -> [[String: Any]]? {
+    public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         
         selectClause.applyToFetchRequest(fetchRequest)
         queryClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.queryAttributes(fetchRequest)
+
+        return try self.queryAttributes(fetchRequest)
     }
     
-    public func queryAttributes<B>(_ clauseChain: B) -> [[String : Any]]? where B : QueryChainableBuilderType, B.ResultType == NSDictionary {
+    public func queryAttributes<B>(_ clauseChain: B) throws -> [[String : Any]] where B : QueryChainableBuilderType, B.ResultType == NSDictionary {
         
-        return self.queryAttributes(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
+        return try self.queryAttributes(clauseChain.from, clauseChain.select, clauseChain.queryClauses)
     }
     
     
@@ -333,22 +318,18 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
     // MARK: Deleting
     
     @nonobjc
-    internal func deleteAll<D>(_ from: From<D>, _ deleteClauses: [FetchClause]) -> Int? {
+    internal func deleteAll<D>(_ from: From<D>, _ deleteClauses: [FetchClause]) throws -> Int {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectResultType
         fetchRequest.returnsObjectsAsFaults = true
         fetchRequest.includesPropertyValues = false
         deleteClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        
-        guard storeFound else {
-            
-            return nil
-        }
-        return self.deleteAll(fetchRequest.dynamicCast())
+
+        return try self.deleteAll(fetchRequest.dynamicCast())
     }
     
     
@@ -384,16 +365,16 @@ internal extension NSManagedObjectContext {
                 fetchError = error
             }
         }
-        if fetchResults == nil {
+        if let fetchResults = fetchResults {
 
-            let coreStoreError = CoreStoreError(fetchError)
-            CoreStore.log(
-                coreStoreError,
-                "Failed executing fetch request."
-            )
-            throw coreStoreError
+            return fetchResults.first
         }
-        return fetchResults?.first
+        let coreStoreError = CoreStoreError(fetchError)
+        CoreStore.log(
+            coreStoreError,
+            "Failed executing fetch request."
+        )
+        throw coreStoreError
     }
     
     @nonobjc
@@ -412,16 +393,16 @@ internal extension NSManagedObjectContext {
                 fetchError = error
             }
         }
-        if fetchResults == nil {
+        if let fetchResults = fetchResults {
 
-            let coreStoreError = CoreStoreError(fetchError)
-            CoreStore.log(
-                coreStoreError,
-                "Failed executing fetch request."
-            )
-            throw coreStoreError
+            return fetchResults
         }
-        return fetchResults
+        let coreStoreError = CoreStoreError(fetchError)
+        CoreStore.log(
+            coreStoreError,
+            "Failed executing fetch request."
+        )
+        throw coreStoreError
     }
     
     @nonobjc
@@ -442,7 +423,7 @@ internal extension NSManagedObjectContext {
         }
         if count == NSNotFound {
 
-            let coreStoreError = CoreStoreError(fetchError)
+            let coreStoreError = CoreStoreError(countError)
             CoreStore.log(
                 coreStoreError,
                 "Failed executing count request."
@@ -453,7 +434,7 @@ internal extension NSManagedObjectContext {
     }
     
     @nonobjc
-    internal func fetchObjectID(_ fetchRequest: NSFetchRequest<NSManagedObjectID>) -> NSManagedObjectID? {
+    internal func fetchObjectID(_ fetchRequest: NSFetchRequest<NSManagedObjectID>) throws -> NSManagedObjectID? {
         
         var fetchResults: [NSManagedObjectID]?
         var fetchError: Error?
@@ -468,22 +449,23 @@ internal extension NSManagedObjectContext {
                 fetchError = error
             }
         }
-        if fetchResults == nil {
-            
-            CoreStore.log(
-                CoreStoreError(fetchError),
-                "Failed executing fetch request."
-            )
-            return nil
+        if let fetchResults = fetchResults {
+
+            return fetchResults.first
         }
-        return fetchResults?.first
+        let coreStoreError = CoreStoreError(fetchError)
+        CoreStore.log(
+            coreStoreError,
+            "Failed executing fetch request."
+        )
+        throw coreStoreError
     }
     
     
     // MARK: Querying
     
     @nonobjc
-    internal func queryValue<D, U: QueryableAttributeType>(_ selectTerms: [SelectTerm<D>], fetchRequest: NSFetchRequest<NSFetchRequestResult>) -> U? {
+    internal func queryValue<D, U: QueryableAttributeType>(_ selectTerms: [SelectTerm<D>], fetchRequest: NSFetchRequest<NSFetchRequestResult>) throws -> U? {
         
         var fetchResults: [Any]?
         var fetchError: Error?
@@ -507,16 +489,16 @@ internal extension NSManagedObjectContext {
             }
             return nil
         }
-        
+        let coreStoreError = CoreStoreError(fetchError)
         CoreStore.log(
-            CoreStoreError(fetchError),
+            coreStoreError,
             "Failed executing fetch request."
         )
-        return nil
+        throw coreStoreError
     }
     
     @nonobjc
-    internal func queryValue<D>(_ selectTerms: [SelectTerm<D>], fetchRequest: NSFetchRequest<NSFetchRequestResult>) -> Any? {
+    internal func queryValue<D>(_ selectTerms: [SelectTerm<D>], fetchRequest: NSFetchRequest<NSFetchRequestResult>) throws -> Any? {
         
         var fetchResults: [Any]?
         var fetchError: Error?
@@ -540,16 +522,16 @@ internal extension NSManagedObjectContext {
             }
             return nil
         }
-        
+        let coreStoreError = CoreStoreError(fetchError)
         CoreStore.log(
-            CoreStoreError(fetchError),
+            coreStoreError,
             "Failed executing fetch request."
         )
-        return nil
+        throw coreStoreError
     }
     
     @nonobjc
-    internal func queryAttributes(_ fetchRequest: NSFetchRequest<NSFetchRequestResult>) -> [[String: Any]]? {
+    internal func queryAttributes(_ fetchRequest: NSFetchRequest<NSFetchRequestResult>) throws -> [[String: Any]] {
         
         var fetchResults: [Any]?
         var fetchError: Error?
@@ -568,19 +550,19 @@ internal extension NSManagedObjectContext {
             
             return NSDictionary.cs_fromQueryResultsNativeType(fetchResults)
         }
-        
+        let coreStoreError = CoreStoreError(fetchError)
         CoreStore.log(
-            CoreStoreError(fetchError),
+            coreStoreError,
             "Failed executing fetch request."
         )
-        return nil
+        throw coreStoreError
     }
     
     
     // MARK: Deleting
     
     @nonobjc
-    internal func deleteAll<D: NSManagedObject>(_ fetchRequest: NSFetchRequest<D>) -> Int? {
+    internal func deleteAll<D: NSManagedObject>(_ fetchRequest: NSFetchRequest<D>) throws -> Int {
         
         var numberOfDeletedObjects: Int?
         var fetchError: Error?
@@ -603,14 +585,15 @@ internal extension NSManagedObjectContext {
                 }
             }
         }
-        if numberOfDeletedObjects == nil {
-            
-            CoreStore.log(
-                CoreStoreError(fetchError),
-                "Failed executing fetch request."
-            )
-            return nil
+        if let numberOfDeletedObjects = numberOfDeletedObjects {
+
+            return numberOfDeletedObjects
         }
-        return numberOfDeletedObjects
+        let coreStoreError = CoreStoreError(fetchError)
+        CoreStore.log(
+            coreStoreError,
+            "Failed executing delete request."
+        )
+        throw coreStoreError
     }
 }

Sources/QueryableSource.swift

@@ -44,7 +44,7 @@ public protocol QueryableSource: class {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) -> U?
+    func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U?
 
     /**
      Queries aggregate values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
@@ -56,7 +56,7 @@ public protocol QueryableSource: class {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) -> U?
+    func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U?
     
     /**
      Queries a property value or aggregate as specified by the `QueryChainableBuilderType` built from a chain of clauses.
@@ -72,7 +72,7 @@ public protocol QueryableSource: class {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) -> B.ResultType? where B.ResultType: QueryableAttributeType
+    func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType
 
     /**
      Queries a dictionary of attribute values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
@@ -84,7 +84,7 @@ public protocol QueryableSource: class {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) -> [[String: Any]]?
+    func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]]
 
     /**
      Queries a dictionary of attribute values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
@@ -96,7 +96,7 @@ public protocol QueryableSource: class {
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
      */
-    func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) -> [[String: Any]]?
+    func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]]
     
     /**
      Queries a dictionary of attribute values or  as specified by the `QueryChainableBuilderType` built from a chain of clauses.
@@ -121,7 +121,7 @@ public protocol QueryableSource: class {
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
      */
-    func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) -> [[String: Any]]? where B.ResultType == NSDictionary
+    func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary
     
     /**
      The internal `NSManagedObjectContext` managed by this `QueryableSource`. Using this context directly should typically be avoided, and is provided by CoreStore only for extremely specialized cases.