Ask to sign in when the Apple data source returns 401

Xcodes/Backend/AppState+Update.swift

@@ -58,8 +58,12 @@ extension AppState {
                 Current.defaults.setDate(Current.date(), forKey: "lastUpdated")
             } catch is CancellationError {
             } catch {
-                // Prevent setting the app state error if it is an invalid session, we will present the sign in view instead
-                if error as? AuthenticationError != .invalidSession {
+                if self.dataSource == .apple, Self.isUnauthorizedInstallError(error) || error as? AuthenticationError == .invalidSession {
+                    // The Apple data source needs a developer session; ask the user to sign in rather than
+                    // showing a raw 401.
+                    self.presentedAlert = .unauthenticatedDataSource
+                } else if error as? AuthenticationError != .invalidSession {
+                    // Prevent setting the app state error if it is an invalid session, we will present the sign in view instead
                     self.error = error
                     self.presentedAlert = .generic(title: localizeString("Alert.Update.Error.Title"), message: error.legibleLocalizedDescription)
                 }

Xcodes/Frontend/Common/XcodesAlert.swift

@@ -8,6 +8,7 @@ enum XcodesAlert: Identifiable {
     case generic(title: String, message: String)
     case checkMinSupportedVersion(xcode: AvailableXcode, macOS: String)
     case unauthenticated
+    case unauthenticatedDataSource
 
     var id: Int {
         switch self {
@@ -17,6 +18,7 @@ enum XcodesAlert: Identifiable {
         case .checkMinSupportedVersion: return 4
         case .cancelRuntimeInstall: return 5
         case .unauthenticated: return 6
+        case .unauthenticatedDataSource: return 7
         }
     }
 }

Xcodes/Frontend/MainWindow.swift

@@ -204,6 +204,20 @@ struct MainWindow: View {
                     Text("Cancel")
                 )
             )
+        case .unauthenticatedDataSource:
+            return Alert(
+                title: Text("Alert.Update.AuthError.Title"),
+                message: Text("Alert.Update.AuthError.Message"),
+                primaryButton: .default(
+                    Text("Login"),
+                    action: {
+                        appState.presentedSheet = .signIn
+                    }
+                ),
+                secondaryButton: .cancel(
+                    Text("Cancel")
+                )
+            )
         case let .checkMinSupportedVersion(xcode, deviceVersion):
             return Alert(
                 title: Text("Alert.MinSupported.Title"),

Xcodes/Resources/Localizable.xcstrings

@@ -4414,6 +4414,26 @@
         }
       }
     },
+    "Alert.Update.AuthError.Message" : {
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "The Apple data source lists Xcode releases from your Apple Developer account, so it needs you to be signed in. Sign in to refresh the list, or switch the data source to Xcode Releases in Settings."
+          }
+        }
+      }
+    },
+    "Alert.Update.AuthError.Title" : {
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sign in to refresh from Apple"
+          }
+        }
+      }
+    },
     "Alert.Update.Error.Title" : {
       "comment" : "Update",
       "extractionState" : "manual",