WIP: make fetching methods throwable

Sources/BaseDataTransaction+Querying.swift

@@ -138,13 +138,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> D? {
+    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchOne(from, fetchClauses)
+        return try self.context.fetchOne(from, fetchClauses)
     }
     
     /**
@@ -154,13 +154,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> D? {
+    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchOne(from, fetchClauses)
+        return try self.context.fetchOne(from, fetchClauses)
     }
     
     /**
@@ -175,13 +175,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
      */
-    public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) -> B.ObjectType? {
+    public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchOne(clauseChain)
+        return try self.context.fetchOne(clauseChain)
     }
     
     /**
@@ -191,13 +191,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [D]? {
+    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchAll(from, fetchClauses)
+        return try self.context.fetchAll(from, fetchClauses)
     }
     
     /**
@@ -207,13 +207,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [D]? {
+    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchAll(from, fetchClauses)
+        return try self.context.fetchAll(from, fetchClauses)
     }
     
     /**
@@ -228,13 +228,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
      */
-    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) -> [B.ObjectType]? {
+    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchAll(clauseChain)
+        return try self.context.fetchAll(clauseChain)
     }
     
     /**
@@ -244,13 +244,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> Int? {
+    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchCount(from, fetchClauses)
+        return try self.context.fetchCount(from, fetchClauses)
     }
     
     /**
@@ -260,13 +260,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> Int? {
+    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchCount(from, fetchClauses)
+        return try self.context.fetchCount(from, fetchClauses)
     }
     
     /**
@@ -281,13 +281,13 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) -> Int? {
+    public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
         CoreStore.assert(
             self.isRunningInAllowedQueue(),
             "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
         )
-        return self.context.fetchCount(clauseChain)
+        return try self.context.fetchCount(clauseChain)
     }
     
     /**

Sources/CSError.swift

@@ -247,6 +247,14 @@ extension CoreStoreError: CoreStoreSwiftType, _ObjectiveCBridgeableError {
             
         case .userCancelled:
             self = .userCancelled
+
+        case .persistentStoreNotFound:
+            guard let entity = info["entity"] as? DynamicObject.Type else {
+
+                self = .unknown
+                return
+            }
+            self = .persistentStoreNotFound(entity: entity)
         }
     }
 }

Sources/CSListMonitor.swift

@@ -132,7 +132,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func hasObjectsInSection(_ section: Int) -> Bool {
         
-        return self.bridgeToSwift.hasObjectsInSection(section)
+        return self.bridgeToSwift.hasObjects(in: section)
     }
     
     /**
@@ -155,7 +155,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func objectsInSection(_ section: Int) -> [NSManagedObject] {
         
-        return self.bridgeToSwift.objectsInSection(section)
+        return self.bridgeToSwift.objects(in: section)
     }
     
     /**
@@ -167,7 +167,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func objectsInSafeSection(safeSectionIndex section: Int) -> [NSManagedObject]? {
         
-        return self.bridgeToSwift.objectsInSection(safeSectionIndex: section)
+        return self.bridgeToSwift.objects(safelyIn: section)
     }
 
     /**
@@ -201,7 +201,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func numberOfObjectsInSection(_ section: Int) -> Int {
         
-        return self.bridgeToSwift.numberOfObjectsInSection(section)
+        return self.bridgeToSwift.numberOfObjects(in: section)
     }
     
     /**
@@ -214,7 +214,7 @@ public final class CSListMonitor: NSObject {
     public func numberOfObjectsInSafeSection(safeSectionIndex section: Int) -> NSNumber? {
         
         return self.bridgeToSwift
-            .numberOfObjectsInSection(safeSectionIndex: section)
+            .numberOfObjects(safelyIn: section)
             .flatMap { NSNumber(value: $0) }
     }
     
@@ -227,7 +227,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func sectionInfoAtIndex(_ section: Int) -> NSFetchedResultsSectionInfo {
         
-        return self.bridgeToSwift.sectionInfoAtIndex(section)
+        return self.bridgeToSwift.sectionInfo(at: section)
     }
     
     /**
@@ -239,7 +239,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func sectionInfoAtSafeSectionIndex(safeSectionIndex section: Int) -> NSFetchedResultsSectionInfo? {
         
-        return self.bridgeToSwift.sectionInfoAtIndex(safeSectionIndex: section)
+        return self.bridgeToSwift.sectionInfo(safelyAt: section)
     }
     
     /**
@@ -263,7 +263,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func targetSectionForSectionIndexTitle(title: String, index: Int) -> Int {
         
-        return self.bridgeToSwift.targetSectionForSectionIndex(title: title, index: index)
+        return self.bridgeToSwift.targetSection(forSectionIndexTitle: title, at: index)
     }
     
     /**
@@ -287,7 +287,7 @@ public final class CSListMonitor: NSObject {
     public func indexOf(_ object: NSManagedObject) -> NSNumber? {
         
         return self.bridgeToSwift
-            .indexOf(object)
+            .index(of: object)
             .flatMap { NSNumber(value: $0) }
     }
     
@@ -300,7 +300,7 @@ public final class CSListMonitor: NSObject {
     @objc
     public func indexPathOf(_ object: NSManagedObject) -> IndexPath? {
         
-        return self.bridgeToSwift.indexPathOf(object)
+        return self.bridgeToSwift.indexPath(of: object)
     }
     
     

Sources/CoreStore+Observing.swift

@@ -113,7 +113,7 @@ public extension CoreStore {
      
      ```
      CoreStore.monitorList(
-         { (monitor) in
+         createAsynchronously: { (monitor) in
              self.monitor = monitor
          },
          From<MyPersonEntity>()
@@ -123,7 +123,6 @@ public extension CoreStore {
      ```
      - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
     public static func monitorList<B: FetchChainableBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
         
@@ -212,7 +211,7 @@ public extension CoreStore {
      Asynchronously creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType` built from a chain of clauses.
      ```
      CoreStore.monitorSectionedList(
-         { (monitor) in
+         createAsynchronously: { (monitor) in
              self.monitor = monitor
          },
          From<MyPersonEntity>()
@@ -221,8 +220,8 @@ public extension CoreStore {
              .orderBy(.ascending(\.age))
      )
      ```
+     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
      - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType`
      */
     public static func monitorSectionedList<B: SectionMonitorBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
         

Sources/CoreStore+Querying.swift

@@ -82,9 +82,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    public static func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> D? {
+    public static func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
-        return self.defaultStack.fetchOne(from, fetchClauses)
+        return try self.defaultStack.fetchOne(from, fetchClauses)
     }
     
     /**
@@ -94,9 +94,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    public static func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> D? {
+    public static func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
-        return self.defaultStack.fetchOne(from, fetchClauses)
+        return try self.defaultStack.fetchOne(from, fetchClauses)
     }
     
     /**
@@ -111,9 +111,9 @@ public extension CoreStore {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
      */
-    public static func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) -> B.ObjectType? {
+    public static func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
-        return self.defaultStack.fetchOne(clauseChain)
+        return try self.defaultStack.fetchOne(clauseChain)
     }
     
     /**
@@ -123,9 +123,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    public static func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [D]? {
+    public static func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
-        return self.defaultStack.fetchAll(from, fetchClauses)
+        return try self.defaultStack.fetchAll(from, fetchClauses)
     }
     
     /**
@@ -135,9 +135,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    public static func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [D]? {
+    public static func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
-        return self.defaultStack.fetchAll(from, fetchClauses)
+        return try self.defaultStack.fetchAll(from, fetchClauses)
     }
     
     /**
@@ -152,9 +152,9 @@ public extension CoreStore {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
      */
-    public static func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) -> [B.ObjectType]? {
+    public static func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
         
-        return self.defaultStack.fetchAll(clauseChain)
+        return try self.defaultStack.fetchAll(clauseChain)
     }
     
     /**
@@ -164,9 +164,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public static func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> Int? {
+    public static func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
         
-        return self.defaultStack.fetchCount(from, fetchClauses)
+        return try self.defaultStack.fetchCount(from, fetchClauses)
     }
     
     /**
@@ -176,9 +176,9 @@ public extension CoreStore {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public static func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> Int? {
+    public static func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
-        return self.defaultStack.fetchCount(from, fetchClauses)
+        return try self.defaultStack.fetchCount(from, fetchClauses)
     }
     
     /**
@@ -193,9 +193,9 @@ public extension CoreStore {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    public static func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) -> Int? {
+    public static func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
-        return self.defaultStack.fetchCount(clauseChain)
+        return try self.defaultStack.fetchCount(clauseChain)
     }
     
     /**

Sources/CoreStoreError.swift

@@ -74,6 +74,11 @@ public enum CoreStoreError: Error, CustomNSError, Hashable {
      */
     case userCancelled
 
+    /**
+     Attempted to perform a fetch but could not find any related persistent store.
+     */
+    case persistentStoreNotFound(entity: DynamicObject.Type)
+    
     
     // MARK: CustomNSError
     
@@ -109,6 +114,9 @@ public enum CoreStoreError: Error, CustomNSError, Hashable {
             
         case .userCancelled:
             return CoreStoreErrorCode.userCancelled.rawValue
+
+        case .persistentStoreNotFound:
+            return CoreStoreErrorCode.persistentStoreNotFound.rawValue
         }
     }
     
@@ -154,6 +162,11 @@ public enum CoreStoreError: Error, CustomNSError, Hashable {
             
         case .userCancelled:
             return [:]
+
+        case .persistentStoreNotFound(let entity):
+            return [
+                "entity": entity
+            ]
         }
     }
     
@@ -196,6 +209,9 @@ public enum CoreStoreError: Error, CustomNSError, Hashable {
         case (.userCancelled, .userCancelled):
             return true
 
+        case (.persistentStoreNotFound(let entity1), .persistentStoreNotFound(let entity2)):
+            return entity1 == entity2
+            
         default:
             return false
         }
@@ -233,6 +249,9 @@ public enum CoreStoreError: Error, CustomNSError, Hashable {
         case .userError(let error):
             hasher.combine(error as NSError)
 
+        case .persistentStoreNotFound(let entity):
+            hasher.combine(ObjectIdentifier(entity))
+
         case .userCancelled:
             break
         }
@@ -303,6 +322,11 @@ public enum CoreStoreErrorCode: Int {
      The transaction was cancelled by the user.
      */
     case userCancelled
+
+    /**
+     Attempted to perform a fetch but could not find any related persistent store.
+     */
+    case persistentStoreNotFound
 }
 
 

Sources/CoreStoreFetchedResultsController.swift

@@ -58,7 +58,7 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
         
         self.reapplyAffectedStores = { fetchRequest, context in
             
-            return from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
+            return try rom.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
         }
         
         super.init(
@@ -72,13 +72,7 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
     @nonobjc
     internal func performFetchFromSpecifiedStores() throws {
 
-        if !self.reapplyAffectedStores(self.fetchRequest, self.managedObjectContext) {
+        try self.reapplyAffectedStores(self.fetchRequest, self.managedObjectContext)
-            
-            CoreStore.log(
-                .warning,
-                message: "Attempted to perform a fetch on an \(cs_typeName(self)) but could not find any persistent store for the entity \(cs_typeName(self.fetchRequest.entityName))"
-            )
-        }
         try self.performFetch()
     }
     
@@ -97,5 +91,5 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
     // MARK: Private
     
     @nonobjc
-    private let reapplyAffectedStores: (_ fetchRequest: NSFetchRequest<NSManagedObject>, _ context: NSManagedObjectContext) -> Bool
+    private let reapplyAffectedStores: (_ fetchRequest: NSFetchRequest<NSManagedObject>, _ context: NSManagedObjectContext) throws -> Bool
 }

Sources/DataStack+Observing.swift

@@ -152,7 +152,7 @@ public extension DataStack {
      
      ```
      dataStack.monitorList(
-         { (monitor) in
+         createAsynchronously: { (monitor) in
              self.monitor = monitor
          },
          From<MyPersonEntity>()
@@ -162,7 +162,6 @@ public extension DataStack {
      ```
      - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
     public func monitorList<B: FetchChainableBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
         
@@ -288,7 +287,7 @@ public extension DataStack {
      Asynchronously creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType` built from a chain of clauses.
      ```
      dataStack.monitorSectionedList(
-         { (monitor) in
+         createAsynchronously: { (monitor) in
              self.monitor = monitor
          },
          From<MyPersonEntity>()
@@ -297,8 +296,8 @@ public extension DataStack {
              .orderBy(.ascending(\.age))
      )
      ```
+     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
      - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType`
      */
     public func monitorSectionedList<B: SectionMonitorBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
         

Sources/DataStack+Querying.swift

@@ -84,13 +84,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> D? {
+    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchOne(from, fetchClauses)
+        return try self.mainContext.fetchOne(from, fetchClauses)
     }
     
     /**
@@ -100,13 +100,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> D? {
+    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchOne(from, fetchClauses)
+        return try self.mainContext.fetchOne(from, fetchClauses)
     }
     
     /**
@@ -121,13 +121,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
      */
-    public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) -> B.ObjectType? {
+    public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchOne(clauseChain)
+        return try self.mainContext.fetchOne(clauseChain)
     }
     
     /**
@@ -137,13 +137,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [D]? {
+    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchAll(from, fetchClauses)
+        return try self.mainContext.fetchAll(from, fetchClauses)
     }
     
     /**
@@ -153,13 +153,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [D]? {
+    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchAll(from, fetchClauses)
+        return try self.mainContext.fetchAll(from, fetchClauses)
     }
     
     /**
@@ -174,13 +174,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
      */
-    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) -> [B.ObjectType]? {
+    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
 
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchAll(clauseChain)
+        return try self.mainContext.fetchAll(clauseChain)
     }
     
     /**
@@ -190,13 +190,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> Int? {
+    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchCount(from, fetchClauses)
+        return try self.mainContext.fetchCount(from, fetchClauses)
     }
     
     /**
@@ -206,13 +206,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> Int? {
+    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchCount(from, fetchClauses)
+        return try self.mainContext.fetchCount(from, fetchClauses)
     }
     
     /**
@@ -227,13 +227,13 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) -> Int? {
+    public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
         CoreStore.assert(
             Thread.isMainThread,
             "Attempted to fetch from a \(cs_typeName(self)) outside the main thread."
         )
-        return self.mainContext.fetchCount(clauseChain)
+        return try self.mainContext.fetchCount(clauseChain)
     }
     
     /**

Sources/FetchableSource.swift

@@ -73,7 +73,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> D?
+    func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D?
 
     /**
      Fetches the first `DynamicObject` instance that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -82,7 +82,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
      */
-    func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> D?
+    func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D?
     
     /**
      Fetches the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType` built from a chain of clauses.
@@ -96,7 +96,7 @@ public protocol FetchableSource: class {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
      */
-    func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) -> B.ObjectType?
+    func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType?
 
     /**
      Fetches all `DynamicObject` instances that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -105,7 +105,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [D]?
+    func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D]
 
     /**
      Fetches all `DynamicObject` instances that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -114,7 +114,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
      */
-    func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [D]?
+    func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D]
     
     /**
      Fetches all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
@@ -128,7 +128,7 @@ public protocol FetchableSource: class {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
      */
-    func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) -> [B.ObjectType]?
+    func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType]
 
     /**
      Fetches the number of `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -137,7 +137,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> Int?
+    func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int
 
     /**
      Fetches the number of `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
@@ -146,7 +146,7 @@ public protocol FetchableSource: class {
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
      - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
      */
-    func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> Int?
+    func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int
     
     /**
      Fetches the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
@@ -160,7 +160,7 @@ public protocol FetchableSource: class {
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
      - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
      */
-    func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) -> Int?
+    func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int
 
     /**
      Fetches the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.

Sources/From.swift

@@ -139,29 +139,40 @@ public struct From<D: DynamicObject> {
         self.findPersistentStores = findPersistentStores
     }
     
-    internal func applyToFetchRequest<ResultType>(_ fetchRequest: NSFetchRequest<ResultType>, context: NSManagedObjectContext, applyAffectedStores: Bool = true) -> Bool {
+    internal func applyToFetchRequest<U>(_ fetchRequest: NSFetchRequest<U>, context: NSManagedObjectContext, applyAffectedStores: Bool = true) throws {
         
         fetchRequest.entity = context.parentStack!.entityDescription(for: EntityIdentifier(self.entityClass))!
         guard applyAffectedStores else {
             
-            return true
+            return
         }
-        if self.applyAffectedStoresForFetchedRequest(fetchRequest, context: context) {
+        do {
 
-            return true
+            try self.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
+        }
+        catch let error as CoreStoreError {
+
+            CoreStore.log(
+                error,
+                "Attempted to perform a fetch but could not find any persistent store for the entity \(cs_typeName(fetchRequest.entityName))"
+            )
+            throw error
+        }
+        catch {
+
+            throw error
         }
-        CoreStore.log(
-            .warning,
-            message: "Attempted to perform a fetch but could not find any persistent store for the entity \(cs_typeName(fetchRequest.entityName))"
-        )
-        return false
     }
     
-    internal func applyAffectedStoresForFetchedRequest<U>(_ fetchRequest: NSFetchRequest<U>, context: NSManagedObjectContext) -> Bool {
+    internal func applyAffectedStoresForFetchedRequest<U>(_ fetchRequest: NSFetchRequest<U>, context: NSManagedObjectContext) throws {
         
         let stores = self.findPersistentStores(context)
         fetchRequest.affectedStores = stores
-        return stores?.isEmpty == false
+        if stores?.isEmpty == false {
+
+            return
+        }
+        throw CoreStoreError.persistentStoreNotFound(entity: self.entityClass)
     }
     
     

Sources/ListMonitor.swift

@@ -136,7 +136,7 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      */
     public subscript(safeSectionIndex sectionIndex: Int, safeItemIndex itemIndex: Int) -> ObjectType? {
         
-        guard let section = self.sectionInfoAtIndex(safeSectionIndex: sectionIndex) else {
+        guard let section = self.sectionInfo(safelyAt: sectionIndex) else {
             
             return nil
         }
@@ -202,9 +202,9 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter section: the section index. Using an index outside the valid range will return `false`.
      - returns: `true` if at least one object in the specified section exists, `false` otherwise
      */
-    public func hasObjectsInSection(_ section: Int) -> Bool {
+    public func hasObjects(in section: Int) -> Bool {
         
-        return self.numberOfObjectsInSection(safeSectionIndex: section)! > 0
+        return self.numberOfObjects(safelyIn: section)! > 0
     }
     
     /**
@@ -241,9 +241,9 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter section: the section index. Using an index outside the valid range will raise an exception.
      - returns: the number of objects in the specified section
      */
-    public func numberOfObjectsInSection(_ section: Int) -> Int {
+    public func numberOfObjects(in section: Int) -> Int {
         
-        return self.sectionInfoAtIndex(section).numberOfObjects
+        return self.sectionInfo(at: section).numberOfObjects
     }
     
     /**
@@ -252,9 +252,9 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter section: the section index. Using an index outside the valid range will return `nil`.
      - returns: the number of objects in the specified section
      */
-    public func numberOfObjectsInSection(safeSectionIndex section: Int) -> Int? {
+    public func numberOfObjects(safelyIn section: Int) -> Int? {
         
-        return self.sectionInfoAtIndex(safeSectionIndex: section)?.numberOfObjects
+        return self.sectionInfo(safelyAt: section)?.numberOfObjects
     }
     
     /**
@@ -263,7 +263,7 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter section: the section index. Using an index outside the valid range will raise an exception.
      - returns: the `NSFetchedResultsSectionInfo` for the specified section
      */
-    public func sectionInfoAtIndex(_ section: Int) -> NSFetchedResultsSectionInfo {
+    public func sectionInfo(at section: Int) -> NSFetchedResultsSectionInfo {
         
         CoreStore.assert(
             !self.isPendingRefetch || Thread.isMainThread,
@@ -278,7 +278,7 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter section: the section index. Using an index outside the valid range will return `nil`.
      - returns: the `NSFetchedResultsSectionInfo` for the specified section, or `nil` if the section index is out of bounds.
      */
-    public func sectionInfoAtIndex(safeSectionIndex section: Int) -> NSFetchedResultsSectionInfo? {
+    public func sectionInfo(safelyAt section: Int) -> NSFetchedResultsSectionInfo? {
         
         CoreStore.assert(
             !self.isPendingRefetch || Thread.isMainThread,
@@ -312,17 +312,17 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
     /**
      Returns the target section for a specified "Section Index" title and index.
      
-     - parameter title: the title of the Section Index
+     - parameter sectionIndexTitle: the title of the Section Index
-     - parameter index: the index of the Section Index
+     - parameter sectionIndex: the index of the Section Index
      - returns: the target section for the specified "Section Index" title and index.
      */
-    public func targetSectionForSectionIndex(title: String, index: Int) -> Int {
+    public func targetSection(forSectionIndexTitle sectionIndexTitle: String, at sectionIndex: Int) -> Int {
         
         CoreStore.assert(
             !self.isPendingRefetch || Thread.isMainThread,
             "Attempted to access a \(cs_typeName(self)) outside the main thread while a refetch is in progress."
         )
-        return self.fetchedResultsController.section(forSectionIndexTitle: title, at: index)
+        return self.fetchedResultsController.section(forSectionIndexTitle: sectionIndexTitle, at: sectionIndex)
     }
     
     /**
@@ -345,7 +345,7 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter object: the `DynamicObject` to search the index of
      - returns: the index of the `DynamicObject` if it exists in the `ListMonitor`'s fetched objects, or `nil` if not found.
      */
-    public func indexOf(_ object: ObjectType) -> Int? {
+    public func index(of object: ObjectType) -> Int? {
         
         CoreStore.assert(
             !self.isPendingRefetch || Thread.isMainThread,
@@ -364,7 +364,7 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
      - parameter object: the `DynamicObject` to search the index of
      - returns: the `IndexPath` of the `DynamicObject` if it exists in the `ListMonitor`'s fetched objects, or `nil` if not found.
      */
-    public func indexPathOf(_ object: ObjectType) -> IndexPath? {
+    public func indexPath(of object: ObjectType) -> IndexPath? {
         
         CoreStore.assert(
             !self.isPendingRefetch || Thread.isMainThread,
@@ -1164,6 +1164,57 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
             try! self.fetchedResultsController.performFetchFromSpecifiedStores()
         }
     }
+
+
+    // MARK: Deprecated
+
+    @available(*, deprecated, renamed: "hasObjects(in:)")
+    public func hasObjectsInSection(_ section: Int) -> Bool {
+
+        return self.hasObjects(in: section)
+    }
+
+    @available(*, deprecated, renamed: "numberOfObjects(in:)")
+    public func numberOfObjectsInSection(_ section: Int) -> Int {
+
+        return self.numberOfObjects(in: section)
+    }
+
+    @available(*, deprecated, renamed: "numberOfObjects(safelyIn:)")
+    public func numberOfObjectsInSection(safeSectionIndex section: Int) -> Int? {
+
+        return self.numberOfObjects(safelyIn: section)
+    }
+
+    @available(*, deprecated, renamed: "sectionInfo(at:)")
+    public func sectionInfoAtIndex(_ section: Int) -> NSFetchedResultsSectionInfo {
+
+        return self.sectionInfo(at: section)
+    }
+
+    @available(*, deprecated, renamed: "sectionInfo(safelyAt:)")
+    public func sectionInfoAtIndex(safeSectionIndex section: Int) -> NSFetchedResultsSectionInfo? {
+
+        return self.sectionInfo(safelyAt: section)
+    }
+
+    @available(*, deprecated, renamed: "targetSection(forSectionIndexTitle:at:)")
+    public func targetSectionForSectionIndex(title: String, index: Int) -> Int {
+
+        return self.targetSection(forSectionIndexTitle: title, at: index)
+    }
+
+    @available(*, deprecated, renamed: "index(of:)")
+    public func indexOf(_ object: ObjectType) -> Int? {
+
+        return self.index(of: object)
+    }
+
+    @available(*, deprecated, renamed: "indexPath(of:)")
+    public func indexPathOf(_ object: ObjectType) -> IndexPath? {
+
+        return self.indexPath(of: object)
+    }
 }
 
     
@@ -1192,9 +1243,9 @@ extension ListMonitor where ListMonitor.ObjectType: NSManagedObject {
      - parameter section: the section index. Using an index outside the valid range will raise an exception.
      - returns: all objects in the specified section
      */
-    public func objectsInSection(_ section: Int) -> [ObjectType] {
+    public func objects(in section: Int) -> [ObjectType] {
         
-        return (self.sectionInfoAtIndex(section).objects as! [ObjectType]?) ?? []
+        return (self.sectionInfo(at: section).objects as! [ObjectType]?) ?? []
     }
     
     /**
@@ -1203,9 +1254,24 @@ extension ListMonitor where ListMonitor.ObjectType: NSManagedObject {
      - parameter section: the section index. Using an index outside the valid range will return `nil`.
      - returns: all objects in the specified section
      */
+    public func objects(safelyIn section: Int) -> [ObjectType]? {
+        
+        return self.sectionInfo(safelyAt: section)?.objects as! [ObjectType]?
+    }
+
+
+    // MARK: Deprecated
+
+    @available(*, deprecated, renamed: "objects(in:)")
+    public func objectsInSection(_ section: Int) -> [ObjectType] {
+
+        return self.objects(in: section)
+    }
+
+    @available(*, deprecated, renamed: "objects(safelyIn:)")
     public func objectsInSection(safeSectionIndex section: Int) -> [ObjectType]? {
 
-        return self.sectionInfoAtIndex(safeSectionIndex: section)?.objects as! [ObjectType]?
+        return self.objects(safelyIn: section)
     }
 }
 
@@ -1236,9 +1302,9 @@ extension ListMonitor where ListMonitor.ObjectType: CoreStoreObject {
      - parameter section: the section index. Using an index outside the valid range will raise an exception.
      - returns: all objects in the specified section
      */
-    public func objectsInSection(_ section: Int) -> [ObjectType] {
+    public func objects(in section: Int) -> [ObjectType] {
         
-        return (self.sectionInfoAtIndex(section).objects ?? [])
+        return (self.sectionInfo(at: section).objects ?? [])
             .map({ ObjectType.cs_fromRaw(object: $0 as! NSManagedObject) })
     }
     
@@ -1248,10 +1314,25 @@ extension ListMonitor where ListMonitor.ObjectType: CoreStoreObject {
      - parameter section: the section index. Using an index outside the valid range will return `nil`.
      - returns: all objects in the specified section
      */
+    public func objects(safelyIn section: Int) -> [ObjectType]? {
+        
+        return (self.sectionInfo(safelyAt: section)?.objects)?
+            .map({ ObjectType.cs_fromRaw(object: $0 as! NSManagedObject) })
+    }
+
+
+    // MARK: Deprecated
+
+    @available(*, deprecated, renamed: "objects(in:)")
+    public func objectsInSection(_ section: Int) -> [ObjectType] {
+
+        return self.objects(in: section)
+    }
+
+    @available(*, deprecated, renamed: "objects(safelyIn:)")
     public func objectsInSection(safeSectionIndex section: Int) -> [ObjectType]? {
 
-        return (self.sectionInfoAtIndex(safeSectionIndex: section)?.objects)?
+        return self.objects(safelyIn: section)
-            .map({ ObjectType.cs_fromRaw(object: $0 as! NSManagedObject) })
     }
 }
 

Sources/NSManagedObjectContext+ObjectiveC.swift

@@ -34,85 +34,65 @@ internal extension NSManagedObjectContext {
     // MARK: Internal
     
     @nonobjc
-    internal func fetchOne(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) -> NSManagedObject? {
+    internal func fetchOne(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) throws -> NSManagedObject? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 1
         fetchRequest.resultType = .managedObjectResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchOne(fetchRequest.dynamicCast())
-            
-            return nil
-        }
-        return self.fetchOne(fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    internal func fetchAll<T: NSManagedObject>(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) -> [T]? {
+    internal func fetchAll<T: NSManagedObject>(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) throws -> [T] {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchAll(fetchRequest.dynamicCast())
-            
-            return nil
-        }
-        return self.fetchAll(fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    internal func fetchCount(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) -> Int? {
+    internal func fetchCount(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) throws -> Int {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchCount(fetchRequest.dynamicCast())
-            
-            return nil
-        }
-        return self.fetchCount(fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    internal func fetchObjectID(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) -> NSManagedObjectID? {
+    internal func fetchObjectID(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) throws -> NSManagedObjectID? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 1
         fetchRequest.resultType = .managedObjectIDResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchObjectID(fetchRequest.dynamicCast())
-            
-            return nil
-        }
-        return self.fetchObjectID(fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    internal func fetchObjectIDs(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) -> [NSManagedObjectID]? {
+    internal func fetchObjectIDs(_ from: CSFrom, _ fetchClauses: [CSFetchClause]) throws -> [NSManagedObjectID] {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
+        try from.bridgeToSwift.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectIDResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchObjectIDs(fetchRequest.dynamicCast())
-            
-            return nil
-        }
-        return self.fetchObjectIDs(fetchRequest.dynamicCast())
     }
     
     @nonobjc

Sources/NSManagedObjectContext+Querying.swift

@@ -101,88 +101,76 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
     }
     
     @nonobjc
-    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> D? {
+    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
-        return self.fetchOne(from, fetchClauses)
+        return try self.fetchOne(from, fetchClauses)
     }
     
     @nonobjc
-    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> D? {
+    public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 1
         fetchRequest.resultType = .managedObjectResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchOne(fetchRequest.dynamicCast()).flatMap(from.entityClass.cs_fromRaw)
-            
-            return nil
-        }
-        return self.fetchOne(fetchRequest.dynamicCast()).flatMap(from.entityClass.cs_fromRaw)
     }
     
     @nonobjc
-    public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) -> B.ObjectType? {
+    public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
-        return self.fetchOne(clauseChain.from, clauseChain.fetchClauses)
+        return try self.fetchOne(clauseChain.from, clauseChain.fetchClauses)
     }
     
     @nonobjc
-    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> [D]? {
+    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
-        return self.fetchAll(from, fetchClauses)
+        return try self.fetchAll(from, fetchClauses)
     }
     
     @nonobjc
-    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [D]? {
+    public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectResultType
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
-            
-            return nil
-        }
         let entityClass = from.entityClass
-        return 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) -> [B.ObjectType]? {
+    public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throw -> [B.ObjectType] {
         
-        return self.fetchAll(clauseChain.from, clauseChain.fetchClauses)
+        return try self.fetchAll(clauseChain.from, clauseChain.fetchClauses)
     }
     
     @nonobjc
-    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) -> Int? {
+    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
     
-        return self.fetchCount(from, fetchClauses)
+        return try self.fetchCount(from, fetchClauses)
     }
     
     @nonobjc
-    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> Int? {
+    public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
 
-        guard storeFound else {
+        return try self.fetchCount(fetchRequest.dynamicCast())
-            
-            return nil
-        }
-        return self.fetchCount(fetchRequest.dynamicCast())
     }
     
     @nonobjc
-    public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) -> Int? {
+    public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
-        return self.fetchCount(clauseChain.from, clauseChain.fetchClauses)
+        return try self.fetchCount(clauseChain.from, clauseChain.fetchClauses)
     }
     
     @nonobjc
@@ -208,7 +196,6 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
         return self.fetchObjectID(fetchRequest.dynamicCast())
     }
 
-    // TODO: docs
     @nonobjc
     public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) -> NSManagedObjectID? {
         
@@ -225,7 +212,7 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
     public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) -> [NSManagedObjectID]? {
         
         let fetchRequest = CoreStoreFetchRequest()
-        let storeFound = from.applyToFetchRequest(fetchRequest, context: self)
+        try from.applyToFetchRequest(fetchRequest, context: self)
         
         fetchRequest.fetchLimit = 0
         fetchRequest.resultType = .managedObjectIDResultType
@@ -238,7 +225,6 @@ extension NSManagedObjectContext: FetchableSource, QueryableSource {
         return self.fetchObjectIDs(fetchRequest.dynamicCast())
     }
 
-    // TODO: docs
     @nonobjc
     public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) -> [NSManagedObjectID]? {
         
@@ -383,7 +369,7 @@ internal extension NSManagedObjectContext {
     // MARK: Fetching
     
     @nonobjc
-    internal func fetchOne<D: NSManagedObject>(_ fetchRequest: NSFetchRequest<D>) -> D? {
+    internal func fetchOne<D: NSManagedObject>(_ fetchRequest: NSFetchRequest<D>) throws -> D? {
         
         var fetchResults: [D]?
         var fetchError: Error?
@@ -400,17 +386,18 @@ internal extension NSManagedObjectContext {
         }
         if fetchResults == nil {
 
+            let coreStoreError = CoreStoreError(fetchError)
             CoreStore.log(
-                CoreStoreError(fetchError),
+                coreStoreError,
                 "Failed executing fetch request."
             )
-            return nil
+            throw coreStoreError
         }
         return fetchResults?.first
     }
     
     @nonobjc
-    internal func fetchAll<D: NSManagedObject>(_ fetchRequest: NSFetchRequest<D>) -> [D]? {
+    internal func fetchAll<D: NSManagedObject>(_ fetchRequest: NSFetchRequest<D>) throws -> [D] {
         
         var fetchResults: [D]?
         var fetchError: Error?
@@ -427,17 +414,18 @@ internal extension NSManagedObjectContext {
         }
         if fetchResults == nil {
 
+            let coreStoreError = CoreStoreError(fetchError)
             CoreStore.log(
-                CoreStoreError(fetchError),
+                coreStoreError,
                 "Failed executing fetch request."
             )
-            return nil
+            throw coreStoreError
         }
         return fetchResults
     }
     
     @nonobjc
-    internal func fetchCount(_ fetchRequest: NSFetchRequest<NSFetchRequestResult>) -> Int? {
+    internal func fetchCount(_ fetchRequest: NSFetchRequest<NSFetchRequestResult>) throws -> Int {
         
         var count = 0
         var countError: Error?
@@ -454,11 +442,12 @@ internal extension NSManagedObjectContext {
         }
         if count == NSNotFound {
 
+            let coreStoreError = CoreStoreError(fetchError)
             CoreStore.log(
-                CoreStoreError(countError),
+                coreStoreError,
                 "Failed executing count request."
             )
-            return nil
+            throw coreStoreError
         }
         return count
     }

Sources/UnsafeDataTransaction+Observing.swift

@@ -143,7 +143,22 @@ public extension UnsafeDataTransaction {
         )
     }
 
-    // TODO: docs
+    /**
+     Asynchronously creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
+
+     ```
+     dataStack.monitorList(
+         createAsynchronously: { (monitor) in
+             self.monitor = monitor
+         },
+         From<MyPersonEntity>()
+             .where(\.age > 18)
+             .orderBy(.ascending(\.age))
+     )
+     ```
+     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
+     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
+     */
     public func monitorList<B: FetchChainableBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
         
         self.monitorList(
@@ -267,8 +282,8 @@ public extension UnsafeDataTransaction {
              .orderBy(.ascending(\.age))
      )
      ```
+     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
      - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType`
      */
     public func monitorSectionedList<B: SectionMonitorBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
         

Sources/Where.swift

@@ -541,7 +541,7 @@ public extension Sequence where Iterator.Element: WhereClauseType {
 
 public extension Where {
     
-    @available(*, deprecated: 4.0, renamed: "&&?")
+    @available(*, deprecated, renamed: "&&?")
     public static func && (left: Where<D>, right: Where<D>?) -> Where<D> {
         
         if let right = right {
@@ -551,7 +551,7 @@ public extension Where {
         return left
     }
     
-    @available(*, deprecated: 4.0, renamed: "&&?")
+    @available(*, deprecated, renamed: "&&?")
     public static func && (left: Where<D>?, right: Where<D>) -> Where<D> {
         
         if let left = left {
@@ -561,7 +561,7 @@ public extension Where {
         return right
     }
     
-    @available(*, deprecated: 4.0, renamed: "||?")
+    @available(*, deprecated, renamed: "||?")
     public static func || (left: Where<D>, right: Where<D>?) -> Where<D> {
         
         if let right = right {
@@ -571,7 +571,7 @@ public extension Where {
         return left
     }
     
-    @available(*, deprecated: 4.0, renamed: "||?")
+    @available(*, deprecated, renamed: "||?")
     public static func || (left: Where<D>?, right: Where<D>) -> Where<D> {
         
         if let left = left {