macos: simpler mechanism to detect no more config errors

Fixes #702

macos/Sources/AppDelegate.swift

@@ -248,8 +248,8 @@ class AppDelegate: NSObject, ObservableObject, NSApplicationDelegate, GhosttyApp
         
         // If we have configuration errors, we need to show them.
         let c = ConfigurationErrorsController.sharedInstance
-        c.model.errors = state.configErrors()
-        if (c.model.errors.count > 0) {
+        c.errors = state.configErrors()
+        if (c.errors.count > 0) {
             if (c.window == nil || !c.window!.isVisible) {
                 c.showWindow(self)
             }

macos/Sources/Features/Settings/ConfigurationErrorsController.swift

@@ -3,43 +3,31 @@ import Cocoa
 import SwiftUI
 import Combine
 
-class ConfigurationErrorsController: NSWindowController, NSWindowDelegate {
+class ConfigurationErrorsController: NSWindowController, NSWindowDelegate, ConfigurationErrorsViewModel {
     /// Singleton for the errors view.
     static let sharedInstance = ConfigurationErrorsController()
     
     override var windowNibName: NSNib.Name? { "ConfigurationErrors" }
     
     /// The data model for this view. Update this directly and the associated view will be updated, too.
-    let model = ConfigurationErrorsView.Model()
-    
-    private var cancellable: AnyCancellable?
+    @Published var errors: [String] = [] {
+        didSet {
+            if (errors.count == 0) {
+                self.window?.performClose(nil)
+            }
+        }
+    }
     
     //MARK: - NSWindowController
     
     override func windowWillLoad() {
         shouldCascadeWindows = false
-        
-        if let c = cancellable { c.cancel() }
-        cancellable = model.$errors.sink { newValue in
-            if (newValue.count == 0) {
-                self.window?.close()
-            }
-        }
     }
     
     override func windowDidLoad() {
         guard let window = window else { return }
         window.center()
         window.level = .popUpMenu
-        window.contentView = NSHostingView(rootView: ConfigurationErrorsView(model: model))
-    }
-    
-    //MARK: - NSWindowDelegate
-    
-    func windowWillClose(_ notification: Notification) {
-        if let cancellable = cancellable {
-            cancellable.cancel()
-            self.cancellable = nil
-        }
+        window.contentView = NSHostingView(rootView: ConfigurationErrorsView(model: self))
     }
 }

macos/Sources/Features/Settings/ConfigurationErrorsView.swift

@@ -1,11 +1,11 @@
 import SwiftUI
 
-struct ConfigurationErrorsView: View {
-    class Model: ObservableObject {
-        @Published var errors: [String] = []
-    }
-    
-    @ObservedObject var model: Model
+protocol ConfigurationErrorsViewModel: ObservableObject {
+    var errors: [String] { get set }
+}
+
+struct ConfigurationErrorsView<ViewModel: ConfigurationErrorsViewModel>: View {
+    @ObservedObject var model: ViewModel
     
     var body: some View {
         VStack {