[PM-26606] Fix most strict warnings in AuthenticatorBridgeKit (#2054)

Author: KatherineInCode

AuthenticatorBridgeKit/AuthenticatorBridgeDataStore.swift

@@ -1,5 +1,5 @@
 import BitwardenKit
-import CoreData
+@preconcurrency import CoreData
 
 // MARK: - AuthenticatorStoreType
 
@@ -20,8 +20,11 @@ public enum AuthenticatorBridgeStoreType {
 private let authenticatorBridgeModelName = "Bitwarden-Authenticator"
 
 /// A data store that manages persisting data across app launches in Core Data.
+/// This is currently marked `@unchecked Sendable` because of how we ensure thread safety of the `backgroundContext`
+/// property. Once we have a minimum version of iOS 16 or higher, we can migrate to the `Synchronization` framework
+/// and make this more properly `Sendable`.
 ///
-public class AuthenticatorBridgeDataStore {
+public final nonisolated class AuthenticatorBridgeDataStore: @unchecked Sendable {
     // MARK: Type Properties
 
     /// The managed object model representing the entities in the database schema. CoreData throws
@@ -41,12 +44,29 @@ public class AuthenticatorBridgeDataStore {
 
     // MARK: Properties
 
+    /// A thread-safe lock for `backgroundContext`. Once we have a minimum of iOS 16, we can use an
+    /// `OSAllocatedUnfairLock` instead.
+    private let _backgroundContextLock = DispatchQueue(label: "backgroundContext.lock")
+
+    /// A private backing for `backgroundContext`. The `backgroundContext` variable provides thread-safe access, and
+    /// is what should be used. Once we have a minimum of iOS 16, this can be converted to an `OSAllocatedUnfairLock`,
+    /// and remove the need for the additional `_backgroundContextLock`.
+    private var _backgroundContext: NSManagedObjectContext?
+
     /// A managed object context which executes on a background queue.
-    private(set) lazy var backgroundContext: NSManagedObjectContext = {
-        let context = persistentContainer.newBackgroundContext()
-        context.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
-        return context
-    }()
+    /// This is the thread-safe version of the backing variable `_backgroundContext`,
+    /// and initializes that property lazily.
+    public var backgroundContext: NSManagedObjectContext {
+        _backgroundContextLock.sync {
+            if let context = _backgroundContext {
+                return context
+            }
+            let newContext = persistentContainer.newBackgroundContext()
+            newContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
+            _backgroundContext = newContext
+            return newContext
+        }
+    }
 
     /// The service used by the application to report non-fatal errors.
     let errorReporter: ErrorReporter

AuthenticatorBridgeKit/SharedKeychain/SharedKeychainService.swift

@@ -29,7 +29,7 @@ public protocol SharedKeychainService: AnyObject {
 // MARK: - SharedKeychainServiceError
 
 /// Enum with possible error cases that can be thrown from `SharedKeychainService`.
-public enum SharedKeychainServiceError: Error, Equatable, CustomNSError {
+public enum SharedKeychainServiceError: Error, Equatable, CustomNSError, Sendable {
     /// When a `KeychainService` is unable to locate an auth key for a given storage key.
     ///
     /// - Parameter KeychainItem: The potential storage key for the auth key.

AuthenticatorBridgeKit/SharedKeychain/SharedKeychainStorage.swift

@@ -4,7 +4,7 @@ import Foundation
 
 /// Enumeration of support Keychain Items that can be placed in the `SharedKeychainRepository`
 ///
-public enum SharedKeychainItem: Equatable, Hashable {
+public enum SharedKeychainItem: Equatable, Hashable, Sendable {
     /// The keychain item for the authenticator encryption key.
     case authenticatorKey
 

project-bwk.yml

@@ -66,6 +66,7 @@ targets:
       base:
         APPLICATION_EXTENSION_API_ONLY: true
         INFOPLIST_FILE: AuthenticatorBridgeKit/Info.plist
+        SWIFT_STRICT_CONCURRENCY: complete
     sources:
       - path: AuthenticatorBridgeKit
         excludes:
@@ -82,6 +83,7 @@ targets:
     settings:
       base:
         INFOPLIST_FILE: AuthenticatorBridgeKit/Tests/TestHelpers/Support/Info.plist
+        SWIFT_STRICT_CONCURRENCY: complete
     sources:
       - path: AuthenticatorBridgeKit
         includes:
@@ -102,6 +104,7 @@ targets:
       base:
         ENABLE_TESTING_SEARCH_PATHS: YES
         INFOPLIST_FILE: AuthenticatorBridgeKit/MocksInfo.plist
+        SWIFT_STRICT_CONCURRENCY: complete
     sources:
       - path: AuthenticatorBridgeKit
         includes: