[Shared] Refactors error handling based on ALTLocalizedError protocol (#1115)

* [Shared] Revises ALTLocalizedError protocol

* Refactors errors to conform to revised ALTLocalizedError protocol

* [Missing Commit] Remaining changes for ALTLocalizedError

* [AltServer] Refactors errors to conform to revised ALTLocalizedError protocol

* [Missing Commit] Declares ALTLocalizedTitleErrorKey + ALTLocalizedDescriptionKey

* Updates Objective-C errors to match revised ALTLocalizedError

* [Missing Commit] Unnecessary ALTLocalizedDescription logic

* [Shared] Refactors NSError.withLocalizedFailure to properly support ALTLocalizedError

* [Shared] Supports adding localized titles to errors via NSError.withLocalizedTitle()

* Revises ErrorResponse logic to support arbitrary errors and user info values

* [Missed Commit] Renames CodableServerError to CodableError

* Merges ConnectionError into OperationError

* [Missed Commit] Doesn’t check ALTWrappedError’s userInfo for localizedDescription

* [Missed] Fixes incorrect errorDomain for ALTErrorEnums

* [Missed] Removes nonexistent ALTWrappedError.h

* Includes source file and line number in OperationError.unknown failureReason

* Adds localizedTitle to AppManager operation errors

* Fixes adding localizedTitle + localizedFailure to ALTWrappedError

* Updates ToastView to use error’s localizedTitle as title

* [Shared] Adds NSError.formattedDetailedDescription(with:)

Returns formatted NSAttributedString containing all user info values intended for displaying to the user.

* [Shared] Updates Error.localizedErrorCode to say “code” instead of “error”

* Conforms ALTLocalizedError to CustomStringConvertible

* Adds “View More Details” option to Error Log context menu to view detailed error description

* [Shared] Fixes NSError.formattedDetailedDescription appearing black in dark mode

* [AltServer] Updates error alert to match revised error logic

Uses error’s localizedTitle as alert title.

* [AltServer] Adds “View More Details” button to error alert to view detailed error info

* [AltServer] Renames InstallError to OperationError and conforms to ALTErrorEnum

* [Shared] Removes CodableError support for Date user info values

Not currently used, and we don’t want to accidentally parse a non-Date as a Date in the meantime.

* [Shared] Includes dynamic UserInfoValueProvider values in NSError.formattedDetailedDescription()

* [Shared] Includes source file + line in NSError.formattedDetailedDescription()

Automatically captures source file + line when throwing ALTErrorEnums.

* [Shared] Captures source file + line for unknown errors

* Removes sourceFunction from OperationError

* Adds localizedTitle to AuthenticationViewController errors

* [Shared] Moves nested ALTWrappedError logic to ALTWrappedError initializer

* [AltServer] Removes now-redundant localized failure from JIT errors

All JIT errors now have a localizedTitle which effectively says the same thing.

* Makes OperationError.Code start at 1000

“Connection errors” subsection starts at 1200.

* [Shared] Updates Error domains to revised [Source].[ErrorType] format

* Updates ALTWrappedError.localizedDescription to prioritize using wrapped NSLocalizedDescription as failure reason

* Makes ALTAppleAPIError codes start at 3000

* [AltServer] Adds relevant localizedFailures to ALTDeviceManager.installApplication() errors

* Revises OperationError failureReasons and recovery suggestions

All failure reasons now read correctly when preceded by a failure reason and “because”.

* Revises ALTServerError error messages
All failure reasons now read correctly when preceded by a failure reason and “because”.

* Most failure reasons now read correctly when preceded by a failure reason and “because”.
* ALTServerErrorUnderlyingError forwards all user info provider calls to underlying error.

* Revises error messages for ALTAppleAPIErrorIncorrectCredentials

* [Missed] Removes NSError+AltStore.swift from AltStore target

* [Shared] Updates AltServerErrorDomain to revised [Source].[ErrorType] format

* [Shared] Removes “code” from Error.localizedErrorCode

* [Shared] Makes ALTServerError codes (appear to) start at 2000

We can’t change the actual error codes without breaking backwards compatibility, so instead we just add 2000 whenever we display ALTServerError codes to the user.

* Moves VerificationError.errorFailure to VerifyAppOperation

* Supports custom failure reason for OperationError.unknown

* [Shared] Changes AltServerErrorDomain to “AltServer.ServerError”

* [Shared] Converts ALTWrappedError to Objective-C class

NSError subclasses must be written in ObjC for Swift.Error <-> NSError bridging to work correctly.

# Conflicts:
#	AltStore.xcodeproj/project.pbxproj

* Fixes decoding CodableError nested user info values

AltStore/Authentication/AuthenticationViewController.swift

@@ -108,7 +108,7 @@ private extension AuthenticationViewController
                 
             case .failure(let error as NSError):
                 DispatchQueue.main.async {
-                    let error = error.withLocalizedFailure(NSLocalizedString("Failed to Log In", comment: ""))
+                    let error = error.withLocalizedTitle(NSLocalizedString("Failed to Log In", comment: ""))
                     
                     let toastView = ToastView(error: error)
                     toastView.textLabel.textColor = .altPink

AltStore/Components/ToastView.swift

@@ -51,45 +51,32 @@ class ToastView: RSTToastView
         var error = error as NSError
         var underlyingError = error.underlyingError
         
-        var preferredDuration: TimeInterval?
-        
         if
             let unwrappedUnderlyingError = underlyingError,
             error.domain == AltServerErrorDomain && error.code == ALTServerError.Code.underlyingError.rawValue
         {
-            // Treat underlyingError as the primary error.
+            // Treat underlyingError as the primary error, but keep localized title + failure.
+            
+            let nsError = (error as NSError)
+            error = (unwrappedUnderlyingError as NSError)
+            
+            if let localizedTitle = nsError.localizedTitle
+            {
+                error = error.withLocalizedTitle(localizedTitle)
+            }
+            
+            if let localizedFailure = nsError.localizedFailure
+            {
+                error = error.withLocalizedFailure(localizedFailure)
+            }
             
-            error = unwrappedUnderlyingError as NSError
             underlyingError = nil
-            
-            preferredDuration = .longToastViewDuration
         }
         
-        let text: String
-        let detailText: String?
-        
-        if let failure = error.localizedFailure
-        {
-            text = failure
-            detailText = error.localizedFailureReason ?? error.localizedRecoverySuggestion ?? underlyingError?.localizedDescription ?? error.localizedDescription
-        }
-        else if let reason = error.localizedFailureReason
-        {
-            text = reason
-            detailText = error.localizedRecoverySuggestion ?? underlyingError?.localizedDescription
-        }
-        else
-        {
-            text = error.localizedDescription
-            detailText = underlyingError?.localizedDescription ?? error.localizedRecoverySuggestion
-        }
+        let text = error.localizedTitle ?? NSLocalizedString("Operation Failed", comment: "")
+        let detailText = error.localizedDescription
         
         self.init(text: text, detailText: detailText)
-        
-        if let preferredDuration = preferredDuration
-        {
-            self.preferredDuration = preferredDuration
-        }
     }
     
     required init(coder aDecoder: NSCoder) {

AltStore/Intents/IntentHandler.swift

@@ -127,7 +127,7 @@ private extension IntentHandler
                     
                     self.finish(intent, response: RefreshAllIntentResponse(code: .success, userActivity: nil))
                 }
-                catch RefreshError.noInstalledApps
+                catch ~RefreshErrorCode.noInstalledApps
                 {
                     self.finish(intent, response: RefreshAllIntentResponse(code: .success, userActivity: nil))
                 }

AltStore/Managing Apps/AppManager.swift

@@ -379,7 +379,7 @@ extension AppManager
                     case .success(let source): fetchedSources.insert(source)
                     case .failure(let error):
                         let source = managedObjectContext.object(with: source.objectID) as! Source
-                        source.error = (error as NSError).sanitizedForCoreData()
+                        source.error = (error as NSError).sanitizedForSerialization()
                         errors[source] = error
                     }
                     
@@ -466,7 +466,7 @@ extension AppManager
         group.completionHandler = { (results) in
             do
             {
-                guard let result = results.values.first else { throw context.error ?? OperationError.unknown }
+                guard let result = results.values.first else { throw context.error ?? OperationError.unknown() }
                 completionHandler(result)
             }
             catch
@@ -485,7 +485,7 @@ extension AppManager
     func update(_ app: InstalledApp, presentingViewController: UIViewController?, context: AuthenticatedOperationContext = AuthenticatedOperationContext(), completionHandler: @escaping (Result<InstalledApp, Error>) -> Void) -> Progress
     {
         guard let storeApp = app.storeApp else {
-            completionHandler(.failure(OperationError.appNotFound))
+            completionHandler(.failure(OperationError.appNotFound(name: app.name)))
             return Progress.discreteProgress(totalUnitCount: 1)
         }
         
@@ -493,7 +493,7 @@ extension AppManager
         group.completionHandler = { (results) in
             do
             {
-                guard let result = results.values.first else { throw OperationError.unknown }
+                guard let result = results.values.first else { throw OperationError.unknown() }
                 completionHandler(result)
             }
             catch
@@ -529,7 +529,7 @@ extension AppManager
         group.completionHandler = { (results) in
             do
             {
-                guard let result = results.values.first else { throw OperationError.unknown }
+                guard let result = results.values.first else { throw OperationError.unknown() }
                 
                 let installedApp = try result.get()
                 assert(installedApp.managedObjectContext != nil)
@@ -571,7 +571,7 @@ extension AppManager
             group.completionHandler = { (results) in
                 do
                 {
-                    guard let result = results.values.first else { throw OperationError.unknown }
+                    guard let result = results.values.first else { throw OperationError.unknown() }
 
                     let installedApp = try result.get()
                     assert(installedApp.managedObjectContext != nil)
@@ -597,7 +597,7 @@ extension AppManager
         group.completionHandler = { (results) in
             do
             {
-                guard let result = results.values.first else { throw OperationError.unknown }
+                guard let result = results.values.first else { throw OperationError.unknown() }
                 
                 let installedApp = try result.get()
                 assert(installedApp.managedObjectContext != nil)
@@ -622,7 +622,7 @@ extension AppManager
         group.completionHandler = { (results) in
             do
             {
-                guard let result = results.values.first else { throw OperationError.unknown }
+                guard let result = results.values.first else { throw OperationError.unknown() }
                 
                 let installedApp = try result.get()
                 assert(installedApp.managedObjectContext != nil)
@@ -1270,7 +1270,7 @@ private extension AppManager
             case .success(let installedApp):
                 completionHandler(.success(installedApp))
                 
-            case .failure(ALTServerError.unknownRequest), .failure(OperationError.appNotFound):
+            case .failure(ALTServerError.unknownRequest), .failure(~OperationError.Code.appNotFound):
                 // Fall back to installation if AltServer doesn't support newer provisioning profile requests,
                 // OR if the cached app could not be found and we may need to redownload it.
                 app.managedObjectContext?.performAndWait { // Must performAndWait to ensure we add operations before we return.
@@ -1544,7 +1544,7 @@ private extension AppManager
         }
         
         guard let application = ALTApplication(fileURL: app.fileURL) else {
-            completionHandler(.failure(OperationError.appNotFound))
+            completionHandler(.failure(OperationError.appNotFound(name: app.name)))
             return progress
         }
         
@@ -1556,7 +1556,7 @@ private extension AppManager
                     let temporaryDirectoryURL = context.temporaryDirectory.appendingPathComponent("AltBackup-" + UUID().uuidString)
                     try FileManager.default.createDirectory(at: temporaryDirectoryURL, withIntermediateDirectories: true, attributes: nil)
                     
-                    guard let altbackupFileURL = Bundle.main.url(forResource: "AltBackup", withExtension: "ipa") else { throw OperationError.appNotFound }
+                    guard let altbackupFileURL = Bundle.main.url(forResource: "AltBackup", withExtension: "ipa") else { throw OperationError.appNotFound(name: "AltBackup") }
                     
                     let unzippedAppBundleURL = try FileManager.default.unzipAppBundle(at: altbackupFileURL, toDirectory: temporaryDirectoryURL)
                     guard let unzippedAppBundle = Bundle(url: unzippedAppBundleURL) else { throw OperationError.invalidApp }
@@ -1663,7 +1663,7 @@ private extension AppManager
                 else
                 {
                     // Not preferred server, so ignore these specific errors and throw serverNotFound instead.
-                    return ConnectionError.serverNotFound
+                    return OperationError(.serverNotFound)
                 }
                 
             default: return error
@@ -1716,8 +1716,40 @@ private extension AppManager
             do { try installedApp.managedObjectContext?.save() }
             catch { print("Error saving installed app.", error) }
         }
-        catch
+        catch let nsError as NSError
         {
+            var appName: String!
+            if let app = operation.app as? (NSManagedObject & AppProtocol)
+            {
+                if let context = app.managedObjectContext
+                {
+                    context.performAndWait {
+                        appName = app.name
+                    }
+                }
+                else
+                {
+                    appName = NSLocalizedString("App", comment: "")
+                }
+            }
+            else
+            {
+                appName = operation.app.name
+            }
+            
+            let localizedTitle: String
+            switch operation
+            {
+            case .install: localizedTitle = String(format: NSLocalizedString("Failed to Install %@", comment: ""), appName)
+            case .refresh: localizedTitle = String(format: NSLocalizedString("Failed to Refresh %@", comment: ""), appName)
+            case .update: localizedTitle = String(format: NSLocalizedString("Failed to Update %@", comment: ""), appName)
+            case .activate: localizedTitle = String(format: NSLocalizedString("Failed to Activate %@", comment: ""), appName)
+            case .deactivate: localizedTitle = String(format: NSLocalizedString("Failed to Deactivate %@", comment: ""), appName)
+            case .backup: localizedTitle = String(format: NSLocalizedString("Failed to Back Up %@", comment: ""), appName)
+            case .restore: localizedTitle = String(format: NSLocalizedString("Failed to Restore %@ Backup", comment: ""), appName)
+            }
+            
+            let error = nsError.withLocalizedTitle(localizedTitle)
             group.set(.failure(error), forAppWithBundleIdentifier: operation.bundleIdentifier)
             
             self.log(error, for: operation)
@@ -1748,7 +1780,7 @@ private extension AppManager
     func log(_ error: Error, for operation: AppOperation)
     {
         // Sanitize NSError on same thread before performing background task.
-        let sanitizedError = (error as NSError).sanitizedForCoreData()
+        let sanitizedError = (error as NSError).sanitizedForSerialization()
         
         let loggedErrorOperation: LoggedError.Operation = {
             switch operation

AltStore/Managing Apps/AppManagerErrors.swift

@@ -22,43 +22,35 @@ extension AppManager
         
         var managedObjectContext: NSManagedObjectContext?
         
+        var localizedTitle: String? {
+            var localizedTitle: String?
+            self.managedObjectContext?.performAndWait {
+                if self.sources?.count == 1
+                {
+                    localizedTitle = NSLocalizedString("Failed to Refresh Store", comment: "")
+                }
+                else if self.errors.count == 1
+                {
+                    guard let source = self.errors.keys.first else { return }
+                    localizedTitle = String(format: NSLocalizedString("Failed to Refresh Source “%@”", comment: ""), source.name)
+                }
+                else
+                {
+                    localizedTitle = String(format: NSLocalizedString("Failed to Refresh %@ Sources", comment: ""), NSNumber(value: self.errors.count))
+                }
+            }
+            
+            return localizedTitle
+        }
+        
         var errorDescription: String? {
             if let error = self.primaryError
             {
                 return error.localizedDescription
             }
-            else
+            else if let error = self.errors.values.first, self.errors.count == 1
             {
-                var localizedDescription: String?
-                
-                self.managedObjectContext?.performAndWait {
-                    if self.sources?.count == 1
-                    {
-                        localizedDescription = NSLocalizedString("Could not refresh store.", comment: "")
-                    }
-                    else if self.errors.count == 1
-                    {
-                        guard let source = self.errors.keys.first else { return }
-                        localizedDescription = String(format: NSLocalizedString("Could not refresh source “%@”.", comment: ""), source.name)
-                    }
-                    else
-                    {
-                        localizedDescription = String(format: NSLocalizedString("Could not refresh %@ sources.", comment: ""), NSNumber(value: self.errors.count))
-                    }
-                }
-                
-                return localizedDescription
-            }
-        }
-        
-        var recoverySuggestion: String? {
-            if let error = self.primaryError as NSError?
-            {
-                return error.localizedRecoverySuggestion
-            }
-            else if self.errors.count == 1
-            {
-                return nil
+                return error.localizedDescription
             }
             else
             {
@@ -67,8 +59,18 @@ extension AppManager
         }
         
         var errorUserInfo: [String : Any] {
-            guard let error = self.errors.values.first, self.errors.count == 1 else { return [:] }
-            return [NSUnderlyingErrorKey: error]
+            let errors = Array(self.errors.values)
+            
+            var userInfo = [String: Any]()
+            userInfo[ALTLocalizedTitleErrorKey] = self.localizedTitle
+            userInfo[NSUnderlyingErrorKey] = self.primaryError
+            
+            if #available(iOS 14.5, *), !errors.isEmpty
+            {
+                userInfo[NSMultipleUnderlyingErrorsKey] = errors
+            }
+            
+            return userInfo
         }
         
         init(_ error: Error)

AltStore/Operations/AuthenticationOperation.swift

@@ -13,7 +13,8 @@ import Network
 import AltStoreCore
 import AltSign
 
-enum AuthenticationError: LocalizedError
+typealias AuthenticationError = AuthenticationErrorCode.Error
+enum AuthenticationErrorCode: Int, ALTErrorEnum, CaseIterable
 {
     case noTeam
     case noCertificate
@@ -21,10 +22,10 @@ enum AuthenticationError: LocalizedError
     case missingPrivateKey
     case missingCertificate
     
-    var errorDescription: String? {
+    var errorFailureReason: String {
         switch self {
-        case .noTeam: return NSLocalizedString("Developer team could not be found.", comment: "")
-        case .noCertificate: return NSLocalizedString("Developer certificate could not be found.", comment: "")
+        case .noTeam: return NSLocalizedString("Your Apple ID has no developer teams.", comment: "")
+        case .noCertificate: return NSLocalizedString("The developer certificate could not be found.", comment: "")
         case .missingPrivateKey: return NSLocalizedString("The certificate's private key could not be found.", comment: "")
         case .missingCertificate: return NSLocalizedString("The certificate could not be found.", comment: "")
         }
@@ -210,7 +211,7 @@ class AuthenticationOperation: ResultOperation<(ALTTeam, ALTCertificate, ALTAppl
                 guard
                     let account = Account.first(satisfying: NSPredicate(format: "%K == %@", #keyPath(Account.identifier), altTeam.account.identifier), in: context),
                     let team = Team.first(satisfying: NSPredicate(format: "%K == %@", #keyPath(Team.identifier), altTeam.identifier), in: context)
-                else { throw AuthenticationError.noTeam }
+                else { throw AuthenticationError(.noTeam) }
                 
                 // Account
                 account.isActiveAccount = true
@@ -429,7 +430,7 @@ private extension AuthenticationOperation
                     }
                     else
                     {
-                        completionHandler(.failure(error ?? OperationError.unknown))
+                        completionHandler(.failure(error ?? OperationError.unknown()))
                     }
                 }
             }
@@ -456,7 +457,7 @@ private extension AuthenticationOperation
             }
             else
             {
-                return completionHandler(.failure(AuthenticationError.noTeam))
+                return completionHandler(.failure(AuthenticationError(.noTeam)))
             }
         }
 
@@ -488,7 +489,7 @@ private extension AuthenticationOperation
                 do
                 {
                     let certificate = try Result(certificate, error).get()
-                    guard let privateKey = certificate.privateKey else { throw AuthenticationError.missingPrivateKey }
+                    guard let privateKey = certificate.privateKey else { throw AuthenticationError(.missingPrivateKey) }
                     
                     ALTAppleAPI.shared.fetchCertificates(for: team, session: session) { (certificates, error) in
                         do
@@ -496,7 +497,7 @@ private extension AuthenticationOperation
                             let certificates = try Result(certificates, error).get()
                             
                             guard let certificate = certificates.first(where: { $0.serialNumber == certificate.serialNumber }) else {
-                                throw AuthenticationError.missingCertificate
+                                throw AuthenticationError(.missingCertificate)
                             }
                             
                             certificate.privateKey = privateKey
@@ -517,7 +518,7 @@ private extension AuthenticationOperation
         
         func replaceCertificate(from certificates: [ALTCertificate])
         {
-            guard let certificate = certificates.first(where: { $0.machineName?.starts(with: "AltStore") == true }) ?? certificates.first else { return completionHandler(.failure(AuthenticationError.noCertificate)) }
+            guard let certificate = certificates.first(where: { $0.machineName?.starts(with: "AltStore") == true }) ?? certificates.first else { return completionHandler(.failure(AuthenticationError(.noCertificate))) }
             
             ALTAppleAPI.shared.revoke(certificate, for: team, session: session) { (success, error) in
                 if let error = error, !success

AltStore/Operations/BackgroundRefreshAppsOperation.swift

@@ -11,11 +11,12 @@ import CoreData
 
 import AltStoreCore
 
-enum RefreshError: LocalizedError
+typealias RefreshError = RefreshErrorCode.Error
+enum RefreshErrorCode: Int, ALTErrorEnum, CaseIterable
 {
     case noInstalledApps
     
-    var errorDescription: String? {
+    var errorFailureReason: String {
         switch self
         {
         case .noInstalledApps: return NSLocalizedString("No active apps require refreshing.", comment: "")
@@ -91,7 +92,7 @@ class BackgroundRefreshAppsOperation: ResultOperation<[String: Result<InstalledA
         super.main()
         
         guard !self.installedApps.isEmpty else {
-            self.finish(.failure(RefreshError.noInstalledApps))
+            self.finish(.failure(RefreshError(.noInstalledApps)))
             return
         }
         
@@ -207,11 +208,11 @@ private extension BackgroundRefreshAppsOperation
                 content.title = NSLocalizedString("Refreshed Apps", comment: "")
                 content.body = NSLocalizedString("All apps have been refreshed.", comment: "")
             }
-            catch ConnectionError.serverNotFound
+            catch ~OperationError.Code.serverNotFound
             {
                 shouldPresentAlert = false
             }
-            catch RefreshError.noInstalledApps
+            catch ~RefreshErrorCode.noInstalledApps
             {
                 shouldPresentAlert = false
             }

AltStore/Operations/BackupAppOperation.swift

@@ -55,7 +55,7 @@ class BackupAppOperation: ResultOperation<Void>
                     let appName = installedApp.name
                     self.appName = appName
                     
-                    guard let altstoreApp = InstalledApp.fetchAltStore(in: context) else { throw OperationError.appNotFound }
+                    guard let altstoreApp = InstalledApp.fetchAltStore(in: context) else { throw OperationError.appNotFound(name: appName) }
                     let altstoreOpenURL = altstoreApp.openAppURL
                     
                     var returnURLComponents = URLComponents(url: altstoreOpenURL, resolvingAgainstBaseURL: false)

AltStore/Operations/DownloadAppOperation.swift

@@ -12,29 +12,13 @@ import Roxas
 import AltStoreCore
 import AltSign
 
-private extension DownloadAppOperation
-{
-    struct DependencyError: ALTLocalizedError
-    {
-        let dependency: Dependency
-        let error: Error
-        
-        var failure: String? {
-            return String(format: NSLocalizedString("Could not download “%@”.", comment: ""), self.dependency.preferredFilename)
-        }
-        
-        var underlyingError: Error? {
-            return self.error
-        }
-    }
-}
-
 @objc(DownloadAppOperation)
 class DownloadAppOperation: ResultOperation<ALTApplication>
 {
     let app: AppProtocol
     let context: AppOperationContext
     
+    private let appName: String
     private let bundleIdentifier: String
     private var sourceURL: URL?
     private let destinationURL: URL
@@ -47,6 +31,7 @@ class DownloadAppOperation: ResultOperation<ALTApplication>
         self.app = app
         self.context = context
         
+        self.appName = app.name
         self.bundleIdentifier = app.bundleIdentifier
         self.sourceURL = app.url
         self.destinationURL = destinationURL
@@ -69,7 +54,7 @@ class DownloadAppOperation: ResultOperation<ALTApplication>
         
         print("Downloading App:", self.bundleIdentifier)
         
-        guard let sourceURL = self.sourceURL else { return self.finish(.failure(OperationError.appNotFound)) }
+        guard let sourceURL = self.sourceURL else { return self.finish(.failure(OperationError.appNotFound(name: self.appName))) }
         
         self.downloadApp(from: sourceURL) { result in
             do
@@ -138,7 +123,7 @@ private extension DownloadAppOperation
                 let fileURL = try result.get()
                 
                 var isDirectory: ObjCBool = false
-                guard FileManager.default.fileExists(atPath: fileURL.path, isDirectory: &isDirectory) else { throw OperationError.appNotFound }
+                guard FileManager.default.fileExists(atPath: fileURL.path, isDirectory: &isDirectory) else { throw OperationError.appNotFound(name: self.appName) }
                 
                 try FileManager.default.createDirectory(at: self.temporaryDirectory, withIntermediateDirectories: true, attributes: nil)
                 
@@ -252,7 +237,7 @@ private extension DownloadAppOperation
             let altstorePlist = try PropertyListDecoder().decode(AltStorePlist.self, from: data)
                         
             var dependencyURLs = Set<URL>()
-            var dependencyError: DependencyError?
+            var dependencyError: Error?
             
             let dispatchGroup = DispatchGroup()
             let progress = Progress(totalUnitCount: Int64(altstorePlist.dependencies.count), parent: self.progress, pendingUnitCount: 1)
@@ -285,7 +270,7 @@ private extension DownloadAppOperation
         }
         catch let error as DecodingError
         {
-            let nsError = (error as NSError).withLocalizedFailure(String(format: NSLocalizedString("Could not download dependencies for %@.", comment: ""), application.name))
+            let nsError = (error as NSError).withLocalizedFailure(String(format: NSLocalizedString("The dependencies for %@ could not be determined.", comment: ""), application.name))
             completionHandler(.failure(nsError))
         }
         catch
@@ -294,7 +279,7 @@ private extension DownloadAppOperation
         }
     }
     
-    func download(_ dependency: Dependency, for application: ALTApplication, progress: Progress, completionHandler: @escaping (Result<URL, DependencyError>) -> Void)
+    func download(_ dependency: Dependency, for application: ALTApplication, progress: Progress, completionHandler: @escaping (Result<URL, Error>) -> Void)
     {
         let downloadTask = self.session.downloadTask(with: dependency.downloadURL) { (fileURL, response, error) in
             do
@@ -315,9 +300,10 @@ private extension DownloadAppOperation
                 
                 completionHandler(.success(destinationURL))
             }
-            catch
+            catch let error as NSError
             {
-                completionHandler(.failure(DependencyError(dependency: dependency, error: error)))
+                let localizedFailure = String(format: NSLocalizedString("The dependency “%@” could not be downloaded.", comment: ""), dependency.preferredFilename)
+                completionHandler(.failure(error.withLocalizedFailure(localizedFailure)))
             }
         }
         progress.addChild(downloadTask.progress, withPendingUnitCount: 1)

AltStore/Operations/FetchProvisioningProfilesOperation.swift

@@ -45,7 +45,7 @@ class FetchProvisioningProfilesOperation: ResultOperation<[String: ALTProvisioni
             let session = self.context.session
         else { return self.finish(.failure(OperationError.invalidParameters)) }
         
-        guard let app = self.context.app else { return self.finish(.failure(OperationError.appNotFound)) }
+        guard let app = self.context.app else { return self.finish(.failure(OperationError.appNotFound(name: nil))) }
         
         self.progress.totalUnitCount = Int64(1 + app.appExtensions.count)
         
@@ -260,7 +260,7 @@ extension FetchProvisioningProfilesOperation
                         {
                             if let expirationDate = sortedExpirationDates.first
                             {
-                                throw OperationError.maximumAppIDLimitReached(application: application, requiredAppIDs: requiredAppIDs, availableAppIDs: availableAppIDs, nextExpirationDate: expirationDate)
+                                throw OperationError.maximumAppIDLimitReached(appName: application.name, requiredAppIDs: requiredAppIDs, availableAppIDs: availableAppIDs, expirationDate: expirationDate)
                             }
                             else
                             {
@@ -281,7 +281,7 @@ extension FetchProvisioningProfilesOperation
                             {
                                 if let expirationDate = sortedExpirationDates.first
                                 {
-                                    throw OperationError.maximumAppIDLimitReached(application: application, requiredAppIDs: requiredAppIDs, availableAppIDs: availableAppIDs, nextExpirationDate: expirationDate)
+                                    throw OperationError.maximumAppIDLimitReached(appName: application.name, requiredAppIDs: requiredAppIDs, availableAppIDs: availableAppIDs, expirationDate: expirationDate)
                                 }
                                 else
                                 {

AltStore/Operations/FindServerOperation.swift

@@ -85,7 +85,7 @@ class FindServerOperation: ResultOperation<Server>
             else
             {
                 // No servers.
-                self.finish(.failure(ConnectionError.serverNotFound))
+                self.finish(.failure(OperationError.serverNotFound))
             }
         }
     }

AltStore/Operations/OperationError.swift

@@ -8,55 +8,135 @@
 
 import Foundation
 import AltSign
+import AltStoreCore
 
-enum OperationError: LocalizedError
+extension OperationError
 {
-    static let domain = OperationError.unknown._domain
+    enum Code: Int, ALTErrorCode, CaseIterable
+    {
+        typealias Error = OperationError
+        
+        /* General */
+        case unknown = 1000
+        case unknownResult
+        case cancelled
+        case timedOut
+        case notAuthenticated
+        case appNotFound
+        case unknownUDID
+        case invalidApp
+        case invalidParameters
+        case maximumAppIDLimitReached
+        case noSources
+        case openAppFailed
+        case missingAppGroup
+        
+        /* Connection */
+        case serverNotFound = 1200
+        case connectionFailed
+        case connectionDropped
+    }
     
-    case unknown
-    case unknownResult
-    case cancelled
-    case timedOut
+    static let unknownResult: OperationError = .init(code: .unknownResult)
+    static let cancelled: OperationError = .init(code: .cancelled)
+    static let timedOut: OperationError = .init(code: .timedOut)
+    static let notAuthenticated: OperationError = .init(code: .notAuthenticated)
+    static let unknownUDID: OperationError = .init(code: .unknownUDID)
+    static let invalidApp: OperationError = .init(code: .invalidApp)
+    static let invalidParameters: OperationError = .init(code: .invalidParameters)
+    static let noSources: OperationError = .init(code: .noSources)
+    static let missingAppGroup: OperationError = .init(code: .missingAppGroup)
     
-    case notAuthenticated
-    case appNotFound
+    static let serverNotFound: OperationError = .init(code: .serverNotFound)
+    static let connectionFailed: OperationError = .init(code: .connectionFailed)
+    static let connectionDropped: OperationError = .init(code: .connectionDropped)
     
-    case unknownUDID
+    static func unknown(failureReason: String? = nil, file: String = #fileID, line: UInt = #line) -> OperationError {
+        OperationError(code: .unknown, failureReason: failureReason, sourceFile: file, sourceLine: line)
+    }
     
-    case invalidApp
-    case invalidParameters
+    static func appNotFound(name: String?) -> OperationError { OperationError(code: .appNotFound, appName: name) }
+    static func openAppFailed(name: String) -> OperationError { OperationError(code: .openAppFailed, appName: name) }
     
-    case maximumAppIDLimitReached(application: ALTApplication, requiredAppIDs: Int, availableAppIDs: Int, nextExpirationDate: Date)
+    static func maximumAppIDLimitReached(appName: String, requiredAppIDs: Int, availableAppIDs: Int, expirationDate: Date) -> OperationError {
+        OperationError(code: .maximumAppIDLimitReached, appName: appName, requiredAppIDs: requiredAppIDs, availableAppIDs: availableAppIDs, expirationDate: expirationDate)
+    }
+}
+
+struct OperationError: ALTLocalizedError
+{
+    let code: Code
     
-    case noSources
+    var errorTitle: String?
+    var errorFailure: String?
     
-    case openAppFailed(name: String)
-    case missingAppGroup
+    var appName: String?
+    var requiredAppIDs: Int?
+    var availableAppIDs: Int?
+    var expirationDate: Date?
     
-    var failureReason: String? {
-        switch self {
-        case .unknown: return NSLocalizedString("An unknown error occured.", comment: "")
+    var sourceFile: String?
+    var sourceLine: UInt?
+    
+    private init(code: Code, failureReason: String? = nil, appName: String? = nil, requiredAppIDs: Int? = nil, availableAppIDs: Int? = nil, expirationDate: Date? = nil,
+                 sourceFile: String? = nil, sourceLine: UInt? = nil)
+    {
+        self.code = code
+        self._failureReason = failureReason
+        
+        self.appName = appName
+        self.requiredAppIDs = requiredAppIDs
+        self.availableAppIDs = availableAppIDs
+        self.expirationDate = expirationDate
+        self.sourceFile = sourceFile
+        self.sourceLine = sourceLine
+    }
+    
+    var errorFailureReason: String {
+        switch self.code
+        {
+        case .unknown:
+            var failureReason = self._failureReason ?? NSLocalizedString("An unknown error occured.", comment: "")
+            guard let sourceFile, let sourceLine else { return failureReason }
+            
+            failureReason += " (\(sourceFile) line \(sourceLine))"
+            return failureReason
+            
         case .unknownResult: return NSLocalizedString("The operation returned an unknown result.", comment: "")
         case .cancelled: return NSLocalizedString("The operation was cancelled.", comment: "")
         case .timedOut: return NSLocalizedString("The operation timed out.", comment: "")
         case .notAuthenticated: return NSLocalizedString("You are not signed in.", comment: "")
-        case .appNotFound: return NSLocalizedString("App not found.", comment: "")
-        case .unknownUDID: return NSLocalizedString("Unknown device UDID.", comment: "")
-        case .invalidApp: return NSLocalizedString("The app is invalid.", comment: "")
+        case .unknownUDID: return NSLocalizedString("AltStore could not determine this device's UDID.", comment: "")
+        case .invalidApp: return NSLocalizedString("The app is in an invalid format.", comment: "")
         case .invalidParameters: return NSLocalizedString("Invalid parameters.", comment: "")
+        case .maximumAppIDLimitReached: return NSLocalizedString("You cannot register more than 10 App IDs within a 7 day period.", comment: "")
         case .noSources: return NSLocalizedString("There are no AltStore sources.", comment: "")
-        case .openAppFailed(let name): return String(format: NSLocalizedString("AltStore was denied permission to launch %@.", comment: ""), name)
-        case .missingAppGroup: return NSLocalizedString("AltStore's shared app group could not be found.", comment: "")
-        case .maximumAppIDLimitReached: return NSLocalizedString("Cannot register more than 10 App IDs.", comment: "")
+        case .missingAppGroup: return NSLocalizedString("AltStore's shared app group could not be accessed.", comment: "")
+
+        case .appNotFound:
+            let appName = self.appName ?? NSLocalizedString("The app", comment: "")
+            return String(format: NSLocalizedString("%@ could not be found.", comment: ""), appName)
+
+        case .openAppFailed:
+            let appName = self.appName ?? NSLocalizedString("the app", comment: "")
+            return String(format: NSLocalizedString("AltStore was denied permission to launch %@.", comment: ""), appName)
+
+        case .serverNotFound: return NSLocalizedString("AltServer could not be found.", comment: "")
+        case .connectionFailed: return NSLocalizedString("A connection to AltServer could not be established.", comment: "")
+        case .connectionDropped: return NSLocalizedString("The connection to AltServer was dropped.", comment: "")
         }
     }
+    private var _failureReason: String?
     
     var recoverySuggestion: String? {
-        switch self
+        switch self.code
         {
-        case .maximumAppIDLimitReached(let application, let requiredAppIDs, let availableAppIDs, let date):
+        case .serverNotFound: return NSLocalizedString("Make sure you're on the same WiFi network as a computer running AltServer, or try connecting this device to your computer via USB.", comment: "")
+        case .maximumAppIDLimitReached:
             let baseMessage = NSLocalizedString("Delete sideloaded apps to free up App ID slots.", comment: "")
-            let message: String
+            guard let appName = self.appName, let requiredAppIDs = self.requiredAppIDs, let availableAppIDs = self.availableAppIDs, let date = self.expirationDate else { return baseMessage }
+            
+            var message: String = ""
             
             if requiredAppIDs > 1
             {
@@ -69,23 +149,25 @@ enum OperationError: LocalizedError
                 default: availableText = String(format: NSLocalizedString("only %@ are available", comment: ""), NSNumber(value: availableAppIDs))
                 }
                 
-                let prefixMessage = String(format: NSLocalizedString("%@ requires %@ App IDs, but %@.", comment: ""), application.name, NSNumber(value: requiredAppIDs), availableText)
-                message = prefixMessage + " " + baseMessage
+                let prefixMessage = String(format: NSLocalizedString("%@ requires %@ App IDs, but %@.", comment: ""), appName, NSNumber(value: requiredAppIDs), availableText)
+                message = prefixMessage + " " + baseMessage + "\n\n"
             }
             else
             {
-                let dateComponents = Calendar.current.dateComponents([.day, .hour, .minute], from: Date(), to: date)
-                
-                let dateComponentsFormatter = DateComponentsFormatter()
-                dateComponentsFormatter.maximumUnitCount = 1
-                dateComponentsFormatter.unitsStyle = .full
-                
-                let remainingTime = dateComponentsFormatter.string(from: dateComponents)!
-                
-                let remainingTimeMessage = String(format: NSLocalizedString("You can register another App ID in %@.", comment: ""), remainingTime)
-                message = baseMessage + " " + remainingTimeMessage
+                message = baseMessage + " "
             }
             
+            let dateComponents = Calendar.current.dateComponents([.day, .hour, .minute], from: Date(), to: date)
+            
+            let dateComponentsFormatter = DateComponentsFormatter()
+            dateComponentsFormatter.maximumUnitCount = 1
+            dateComponentsFormatter.unitsStyle = .full
+            
+            let remainingTime = dateComponentsFormatter.string(from: dateComponents)!
+            
+            let remainingTimeMessage = String(format: NSLocalizedString("You can register another App ID in %@.", comment: ""), remainingTime)
+            message += remainingTimeMessage
+            
             return message
             
         default: return nil

AltStore/Operations/Patch App/PatchAppOperation.swift

@@ -25,21 +25,41 @@ protocol PatchAppContext
     var error: Error? { get }
 }
 
-enum PatchAppError: LocalizedError
+extension PatchAppError
 {
-    case unsupportedOperatingSystemVersion(OperatingSystemVersion)
+    enum Code: Int, ALTErrorCode, CaseIterable
+    {
+        typealias Error = PatchAppError
+        
+        case unsupportedOperatingSystemVersion
+    }
     
-    var errorDescription: String? {
-        switch self
+    static func unsupportedOperatingSystemVersion(_ osVersion: OperatingSystemVersion) -> PatchAppError { PatchAppError(code: .unsupportedOperatingSystemVersion, osVersion: osVersion) }
+}
+
+struct PatchAppError: ALTLocalizedError
+{
+    let code: Code
+    var errorFailure: String?
+    var errorTitle: String?
+    
+    var osVersion: OperatingSystemVersion?
+    
+    var errorFailureReason: String {
+        switch self.code
         {
-        case .unsupportedOperatingSystemVersion(let osVersion):
-            var osVersionString = "\(osVersion.majorVersion).\(osVersion.minorVersion)"
-            if osVersion.patchVersion != 0
+        case .unsupportedOperatingSystemVersion:
+            let osVersionString: String
+            if let osVersion = self.osVersion?.stringValue
             {
-                osVersionString += ".\(osVersion.patchVersion)"
+                osVersionString = NSLocalizedString("iOS", comment: "") + " " + osVersion
+            }
+            else
+            {
+                osVersionString = NSLocalizedString("your device's iOS version", comment: "")
             }
             
-            let errorDescription = String(format: NSLocalizedString("The OTA download URL for iOS %@ could not be determined.", comment: ""), osVersionString)
+            let errorDescription = String(format: NSLocalizedString("The OTA download URL for %@ could not be determined.", comment: ""), osVersionString)
             return errorDescription
         }
     }

AltStore/Operations/Patch App/PatchViewController.swift

@@ -439,7 +439,7 @@ private extension PatchViewController
                             
                             do
                             {
-                                guard let (bundleIdentifier, result) = results.first else { throw refreshGroup?.context.error ?? OperationError.unknown }
+                                guard let (bundleIdentifier, result) = results.first else { throw refreshGroup?.context.error ?? OperationError.unknown() }
                                 _ = try result.get()
                                 
                                 if var patchedApps = UserDefaults.standard.patchedApps, let index = patchedApps.firstIndex(of: bundleIdentifier)

AltStore/Operations/RefreshAppOperation.swift

@@ -41,7 +41,7 @@ class RefreshAppOperation: ResultOperation<InstalledApp>
             
             guard let server = self.context.server, let profiles = self.context.provisioningProfiles else { throw OperationError.invalidParameters }
             
-            guard let app = self.context.app else { throw OperationError.appNotFound }
+            guard let app = self.context.app else { throw OperationError.appNotFound(name: nil) }
             guard let udid = Bundle.main.object(forInfoDictionaryKey: Bundle.Info.deviceID) as? String else { throw OperationError.unknownUDID }
             
             ServerManager.shared.connect(to: server) { (result) in
@@ -84,7 +84,7 @@ class RefreshAppOperation: ResultOperation<InstalledApp>
                                         self.managedObjectContext.perform {
                                             let predicate = NSPredicate(format: "%K == %@", #keyPath(InstalledApp.bundleIdentifier), app.bundleIdentifier)
                                             guard let installedApp = InstalledApp.first(satisfying: predicate, in: self.managedObjectContext) else {
-                                                return self.finish(.failure(OperationError.appNotFound))
+                                                return self.finish(.failure(OperationError.appNotFound(name: app.name)))
                                             }
                                             
                                             self.progress.completedUnitCount += 1

AltStore/Operations/VerifyAppOperation.swift

@@ -8,48 +8,74 @@
 
 import Foundation
 
+import AltStoreCore
 import AltSign
 import Roxas
 
-enum VerificationError: ALTLocalizedError
+extension VerificationError
 {
-    case privateEntitlements(ALTApplication, entitlements: [String: Any])
-    case mismatchedBundleIdentifiers(ALTApplication, sourceBundleID: String)
-    case iOSVersionNotSupported(ALTApplication)
-    
-    var app: ALTApplication {
-        switch self
-        {
-        case .privateEntitlements(let app, _): return app
-        case .mismatchedBundleIdentifiers(let app, _): return app
-        case .iOSVersionNotSupported(let app): return app
-        }
+    enum Code: Int, ALTErrorCode, CaseIterable
+    {
+        typealias Error = VerificationError
+        
+        case privateEntitlements
+        case mismatchedBundleIdentifiers
+        case iOSVersionNotSupported
     }
     
-    var failure: String? {
-        return String(format: NSLocalizedString("“%@” could not be installed.", comment: ""), app.name)
-    }
+    static func privateEntitlements(_ entitlements: [String: Any], app: ALTApplication) -> VerificationError { VerificationError(code: .privateEntitlements, app: app, entitlements: entitlements) }
+    static func mismatchedBundleIdentifiers(sourceBundleID: String, app: ALTApplication) -> VerificationError  { VerificationError(code: .mismatchedBundleIdentifiers, app: app, sourceBundleID: sourceBundleID) }
+    static func iOSVersionNotSupported(app: ALTApplication) -> VerificationError  { VerificationError(code: .iOSVersionNotSupported, app: app) }
+}
+
+struct VerificationError: ALTLocalizedError
+{
+    let code: Code
     
-    var failureReason: String? {
-        switch self
+    var errorTitle: String?
+    var errorFailure: String?
+    
+    var app: ALTApplication?
+    var entitlements: [String: Any]?
+    var sourceBundleID: String?
+    
+    
+    var errorFailureReason: String {
+        switch self.code
         {
-        case .privateEntitlements(let app, _):
-            return String(format: NSLocalizedString("“%@” requires private permissions.", comment: ""), app.name)
+        case .privateEntitlements:
+            let appName = (self.app?.name as String?).map { String(format: NSLocalizedString("“%@”", comment: ""), $0) } ?? NSLocalizedString("The app", comment: "")
+            return String(format: NSLocalizedString("%@ requires private permissions.", comment: ""), appName)
             
-        case .mismatchedBundleIdentifiers(let app, let sourceBundleID):
-            return String(format: NSLocalizedString("The bundle ID “%@” does not match the one specified by the source (“%@”).", comment: ""), app.bundleIdentifier, sourceBundleID)
-            
-        case .iOSVersionNotSupported(let app):
-            let name = app.name
-            
-            var version = "iOS \(app.minimumiOSVersion.majorVersion).\(app.minimumiOSVersion.minorVersion)"
-            if app.minimumiOSVersion.patchVersion > 0
+        case .mismatchedBundleIdentifiers:
+            if let app = self.app, let bundleID = self.sourceBundleID
             {
-                version += ".\(app.minimumiOSVersion.patchVersion)"
+                return String(format: NSLocalizedString("The bundle ID “%@” does not match the one specified by the source (“%@”).", comment: ""), app.bundleIdentifier, bundleID)
+            }
+            else
+            {
+                return NSLocalizedString("The bundle ID does not match the one specified by the source.", comment: "")
             }
             
-            let localizedDescription = String(format: NSLocalizedString("%@ requires %@.", comment: ""), name, version)
-            return localizedDescription
+        case .iOSVersionNotSupported:
+            if let app = self.app
+            {
+                var version = "iOS \(app.minimumiOSVersion.majorVersion).\(app.minimumiOSVersion.minorVersion)"
+                if app.minimumiOSVersion.patchVersion > 0
+                {
+                    version += ".\(app.minimumiOSVersion.patchVersion)"
+                }
+                
+                let failureReason = String(format: NSLocalizedString("%@ requires %@.", comment: ""), app.name, version)
+                return failureReason
+            }
+            else
+            {
+                let version = ProcessInfo.processInfo.operatingSystemVersion.stringValue
+                
+                let failureReason = String(format: NSLocalizedString("This app does not support iOS %@.", comment: ""), version)
+                return failureReason
+            }
         }
     }
 }
@@ -78,14 +104,17 @@ class VerifyAppOperation: ResultOperation<Void>
                 throw error
             }
             
+            let appName = self.context.app?.name ?? NSLocalizedString("The app", comment: "")
+            self.localizedFailure = String(format: NSLocalizedString("%@ could not be installed.", comment: ""), appName)
+            
             guard let app = self.context.app else { throw OperationError.invalidParameters }
             
             guard app.bundleIdentifier == self.context.bundleIdentifier else {
-                throw VerificationError.mismatchedBundleIdentifiers(app, sourceBundleID: self.context.bundleIdentifier)
+                throw VerificationError.mismatchedBundleIdentifiers(sourceBundleID: self.context.bundleIdentifier, app: app)
             }
             
             guard ProcessInfo.processInfo.isOperatingSystemAtLeast(app.minimumiOSVersion) else {
-                throw VerificationError.iOSVersionNotSupported(app)
+                throw VerificationError.iOSVersionNotSupported(app: app)
             }
             
             if #available(iOS 13.5, *)
@@ -116,7 +145,7 @@ class VerifyAppOperation: ResultOperation<Void>
                     let entitlements = try PropertyListSerialization.propertyList(from: entitlementsPlist.data(using: .utf8)!, options: [], format: nil) as! [String: Any]
                     
                     app.hasPrivateEntitlements = true
-                    let error = VerificationError.privateEntitlements(app, entitlements: entitlements)
+                    let error = VerificationError.privateEntitlements(entitlements, app: app)
                     self.process(error) { (result) in
                         self.finish(result.mapError { $0 as Error })
                     }
@@ -145,15 +174,16 @@ private extension VerifyAppOperation
         guard let presentingViewController = self.context.presentingViewController else { return completion(.failure(error)) }
         
         DispatchQueue.main.async {
-            switch error
+            switch error.code
             {
-            case .privateEntitlements(_, let entitlements):
+            case .privateEntitlements:
+                guard let entitlements = error.entitlements else { return completion(.failure(error)) }
                 let permissions = entitlements.keys.sorted().joined(separator: "\n")
                 let message = String(format: NSLocalizedString("""
                     You must allow access to these private permissions before continuing:
-
+                    
                     %@
-
+                    
                     Private permissions allow apps to do more than normally allowed by iOS, including potentially accessing sensitive private data. Make sure to only install apps from sources you trust.
                     """, comment: ""), permissions)
                 

AltStore/Server/Server.swift

@@ -8,22 +8,6 @@
 
 import Network
 
-enum ConnectionError: LocalizedError
-{
-    case serverNotFound
-    case connectionFailed
-    case connectionDropped
-    
-    var failureReason: String? {
-        switch self
-        {
-        case .serverNotFound: return NSLocalizedString("Could not find AltServer.", comment: "")
-        case .connectionFailed: return NSLocalizedString("Could not connect to AltServer.", comment: "")
-        case .connectionDropped: return NSLocalizedString("The connection to AltServer was dropped.", comment: "")
-        }
-    }
-}
-
 extension Server
 {
     enum ConnectionType

AltStore/Server/ServerManager.swift

@@ -171,7 +171,7 @@ private extension ServerManager
             {
             case .failed(let error):
                 print("Failed to connect to service \(server.service?.name ?? "").", error)
-                completion(.failure(ConnectionError.connectionFailed))
+                completion(.failure(OperationError.connectionFailed))
                 
             case .cancelled:
                 completion(.failure(OperationError.cancelled))
@@ -192,7 +192,7 @@ private extension ServerManager
     
     func connectToLocalServer(_ server: Server, completion: @escaping (Result<Connection, Error>) -> Void)
     {
-        guard let machServiceName = server.machServiceName else { return completion(.failure(ConnectionError.connectionFailed)) }
+        guard let machServiceName = server.machServiceName else { return completion(.failure(OperationError.connectionFailed)) }
         
         let xpcConnection = NSXPCConnection.makeConnection(machServiceName: machServiceName)
         

AltStore/Settings/Error Log/ErrorDetailsViewController.swift

@@ -0,0 +1,53 @@
+//
+//  ErrorDetailsViewController.swift
+//  AltStore
+//
+//  Created by Riley Testut on 10/5/22.
+//  Copyright © 2022 Riley Testut. All rights reserved.
+//
+
+import UIKit
+
+import AltStoreCore
+
+class ErrorDetailsViewController: UIViewController
+{
+    var loggedError: LoggedError?
+    
+    @IBOutlet private var textView: UITextView!
+    
+    override func viewDidLoad()
+    {
+        super.viewDidLoad()
+        
+        if let error = self.loggedError?.error
+        {
+            self.title = error.localizedErrorCode
+            
+            let font = self.textView.font ?? UIFont.preferredFont(forTextStyle: .body)
+            let detailedDescription = error.formattedDetailedDescription(with: font)
+            self.textView.attributedText = detailedDescription
+        }
+        else
+        {
+            self.title = NSLocalizedString("Error Details", comment: "")
+        }
+        
+        self.navigationController?.navigationBar.tintColor = .altPrimary
+        
+        if #available(iOS 15, *), let sheetController = self.navigationController?.sheetPresentationController
+        {
+            sheetController.detents = [.medium(), .large()]
+            sheetController.selectedDetentIdentifier = .medium
+            sheetController.prefersGrabberVisible = true
+        }
+    }
+    
+    override func viewDidLayoutSubviews()
+    {
+        super.viewDidLayoutSubviews()
+        
+        self.textView.textContainerInset.left = self.view.layoutMargins.left
+        self.textView.textContainerInset.right = self.view.layoutMargins.right
+    }
+}

AltStore/Settings/Error Log/ErrorLogViewController.swift

@@ -37,6 +37,20 @@ class ErrorLogViewController: UITableViewController
         self.tableView.dataSource = self.dataSource
         self.tableView.prefetchDataSource = self.dataSource
     }
+    
+    override func prepare(for segue: UIStoryboardSegue, sender: Any?)
+    {
+        guard let loggedError = sender as? LoggedError, segue.identifier == "showErrorDetails" else { return }
+        
+        let navigationController = segue.destination as! UINavigationController
+        
+        let errorDetailsViewController = navigationController.viewControllers.first as! ErrorDetailsViewController
+        errorDetailsViewController.loggedError = loggedError
+    }
+    
+    @IBAction private func unwindFromErrorDetails(_ segue: UIStoryboardSegue)
+    {
+    }
 }
 
 private extension ErrorLogViewController
@@ -58,13 +72,7 @@ private extension ErrorLogViewController
             let cell = cell as! ErrorLogTableViewCell
             cell.dateLabel.text = self.timeFormatter.string(from: loggedError.date)
             cell.errorFailureLabel.text = loggedError.localizedFailure ?? NSLocalizedString("Operation Failed", comment: "")
-            
-            switch loggedError.domain
-            {
-            case AltServerErrorDomain: cell.errorCodeLabel?.text = String(format: NSLocalizedString("AltServer Error %@", comment: ""), NSNumber(value: loggedError.code))
-            case OperationError.domain: cell.errorCodeLabel?.text = String(format: NSLocalizedString("AltStore Error %@", comment: ""), NSNumber(value: loggedError.code))
-            default: cell.errorCodeLabel?.text = loggedError.error.localizedErrorCode
-            }
+            cell.errorCodeLabel.text = loggedError.error.localizedErrorCode
             
             let nsError = loggedError.error as NSError
             let errorDescription = [nsError.localizedDescription, nsError.localizedRecoverySuggestion].compactMap { $0 }.joined(separator: "\n\n")
@@ -91,7 +99,10 @@ private extension ErrorLogViewController
                     },
                     UIAction(title: NSLocalizedString("Search FAQ", comment: ""), image: UIImage(systemName: "magnifyingglass")) { [weak self] _ in
                         self?.searchFAQ(for: loggedError)
-                    }
+                    },
+                    UIAction(title: NSLocalizedString("View More Details", comment: ""), image: UIImage(systemName: "ellipsis.circle")) { [weak self] _ in
+                        self?.viewMoreDetails(for: loggedError)
+                    },
                 ])
 
                 cell.menuButton.menu = menu
@@ -224,13 +235,18 @@ private extension ErrorLogViewController
         let baseURL = URL(string: "https://faq.altstore.io/getting-started/troubleshooting-guide")!
         var components = URLComponents(url: baseURL, resolvingAgainstBaseURL: false)!
         
-        let query = [loggedError.domain, "\(loggedError.code)"].joined(separator: "+")
+        let query = [loggedError.domain, "\(loggedError.error.displayCode)"].joined(separator: "+")
         components.queryItems = [URLQueryItem(name: "q", value: query)]
         
         let safariViewController = SFSafariViewController(url: components.url ?? baseURL)
         safariViewController.preferredControlTintColor = .altPrimary
         self.present(safariViewController, animated: true)
     }
+    
+    func viewMoreDetails(for loggedError: LoggedError)
+    {
+        self.performSegue(withIdentifier: "showErrorDetails", sender: loggedError)
+    }
 }
 
 extension ErrorLogViewController

AltStore/Settings/Settings.storyboard

@@ -991,11 +991,73 @@ Settings by i cons from the Noun Project</string>
                             </connections>
                         </barButtonItem>
                     </navigationItem>
+                    <connections>
+                        <segue destination="7gm-d1-zWK" kind="presentation" identifier="showErrorDetails" id="9vz-y6-evp"/>
+                    </connections>
                 </tableViewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="rU1-TZ-TD8" userLabel="First Responder" sceneMemberID="firstResponder"/>
             </objects>
             <point key="canvasLocation" x="1697" y="1774"/>
         </scene>
+        <!--Error Details View Controller-->
+        <scene sceneID="XNO-Yg-I7t">
+            <objects>
+                <viewController id="xB2-Se-VVg" customClass="ErrorDetailsViewController" customModule="AltStore" customModuleProvider="target" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="eBQ-se-VIy">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="647"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <textView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" editable="NO" textAlignment="natural" translatesAutoresizingMaskIntoConstraints="NO" id="ctd-NB-4ov">
+                                <rect key="frame" x="0.0" y="0.0" width="375" height="647"/>
+                                <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                                <color key="textColor" systemColor="labelColor"/>
+                                <fontDescription key="fontDescription" style="UICTFontTextStyleBody"/>
+                                <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/>
+                            </textView>
+                        </subviews>
+                        <viewLayoutGuide key="safeArea" id="Nm8-69-Ngi"/>
+                        <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                        <constraints>
+                            <constraint firstItem="ctd-NB-4ov" firstAttribute="leading" secondItem="eBQ-se-VIy" secondAttribute="leading" id="Cv1-Te-gBH"/>
+                            <constraint firstItem="ctd-NB-4ov" firstAttribute="top" secondItem="eBQ-se-VIy" secondAttribute="top" id="HRY-Rg-iMI"/>
+                            <constraint firstAttribute="trailing" secondItem="ctd-NB-4ov" secondAttribute="trailing" id="Lc1-K7-iuq"/>
+                            <constraint firstAttribute="bottom" secondItem="ctd-NB-4ov" secondAttribute="bottom" id="zCz-Cy-Y5z"/>
+                        </constraints>
+                    </view>
+                    <navigationItem key="navigationItem" id="XpE-V9-EaY">
+                        <barButtonItem key="rightBarButtonItem" style="done" systemItem="done" id="rnr-dX-4Ev">
+                            <connections>
+                                <segue destination="ZSp-1n-UJ9" kind="unwind" unwindAction="unwindFromErrorDetails:" id="TFu-zD-QyF"/>
+                            </connections>
+                        </barButtonItem>
+                    </navigationItem>
+                    <connections>
+                        <outlet property="textView" destination="ctd-NB-4ov" id="x2C-9R-Xz1"/>
+                    </connections>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="8AM-Vx-XTN" userLabel="First Responder" customClass="UIResponder" sceneMemberID="firstResponder"/>
+                <exit id="ZSp-1n-UJ9" userLabel="Exit" sceneMemberID="exit"/>
+            </objects>
+            <point key="canvasLocation" x="3389.5999999999999" y="1772.5637181409297"/>
+        </scene>
+        <!--Navigation Controller-->
+        <scene sceneID="4LJ-Od-dCK">
+            <objects>
+                <navigationController automaticallyAdjustsScrollViewInsets="NO" id="7gm-d1-zWK" sceneMemberID="viewController">
+                    <toolbarItems/>
+                    <navigationBar key="navigationBar" contentMode="scaleToFill" id="dI0-sh-yGf">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="56"/>
+                        <autoresizingMask key="autoresizingMask"/>
+                    </navigationBar>
+                    <nil name="viewControllers"/>
+                    <connections>
+                        <segue destination="xB2-Se-VVg" kind="relationship" relationship="rootViewController" id="RpP-UM-JfJ"/>
+                    </connections>
+                </navigationController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="OXW-bf-HIj" userLabel="First Responder" customClass="UIResponder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="2554" y="1773"/>
+        </scene>
     </scenes>
     <resources>
         <image name="Next" width="18" height="18"/>
@@ -1009,5 +1071,8 @@ Settings by i cons from the Noun Project</string>
         <systemColor name="labelColor">
             <color red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
         </systemColor>
+        <systemColor name="systemBackgroundColor">
+            <color white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+        </systemColor>
     </resources>
 </document>

AltStore/Sources/SourcesViewController.swift

@@ -12,17 +12,22 @@ import CoreData
 import AltStoreCore
 import Roxas
 
-struct SourceError: LocalizedError
+struct SourceError: ALTLocalizedError
 {
-    enum Code
+    enum Code: Int, ALTErrorCode
     {
+        typealias Error = SourceError
+        
         case unsupported
     }
     
     var code: Code
+    var errorTitle: String?
+    var errorFailure: String?
+    
     @Managed var source: Source
     
-    var errorDescription: String? {
+    var errorFailureReason: String {
         switch self.code
         {
         case .unsupported: return String(format: NSLocalizedString("The source “%@” is not supported by this version of AltStore.", comment: ""), self.$source.name)