Fix desktop lifetime non-mainwindow cancellation

src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading;
 using Avalonia.Collections;
@@ -184,11 +183,12 @@ private bool DoShutdown(
                 // When an OS shutdown request is received, try to close all non-owned windows. Windows can cancel
                 // shutdown by setting e.Cancel = true in the Closing event. Owned windows will be shutdown by their
                 // owners.
-                foreach (var w in Windows.ToArray())
+                foreach (var w in new List<Window>(_windows))
                 {
                     if (w.Owner is null)
                     {
-                        w.CloseCore(WindowCloseReason.ApplicationShutdown, isProgrammatic);
+                        var ignoreCancel = force || (ShutdownMode == ShutdownMode.OnMainWindowClose && w != MainWindow);
+                        w.CloseCore(WindowCloseReason.ApplicationShutdown, isProgrammatic, ignoreCancel);
                     }
                 }
 

src/Avalonia.Controls/Window.cs

@@ -461,7 +461,7 @@ public PixelPoint Position
         /// </summary>
         public void Close()
         {
-            CloseCore(WindowCloseReason.WindowClosing, true);
+            CloseCore(WindowCloseReason.WindowClosing, true, false);
         }
 
         /// <summary>
@@ -477,10 +477,10 @@ public void Close()
         public void Close(object? dialogResult)
         {
             _dialogResult = dialogResult;
-            CloseCore(WindowCloseReason.WindowClosing, true);
+            CloseCore(WindowCloseReason.WindowClosing, true, false);
         }
 
-        internal void CloseCore(WindowCloseReason reason, bool isProgrammatic)
+        internal void CloseCore(WindowCloseReason reason, bool isProgrammatic, bool ignoreCancel)
         {
             bool close = true;
 
@@ -493,7 +493,7 @@ internal void CloseCore(WindowCloseReason reason, bool isProgrammatic)
             }
             finally
             {
-                if (close)
+                if (close || ignoreCancel)
                 {
                     CloseInternal();
                 }
@@ -1113,10 +1113,12 @@ protected sealed override Size ArrangeSetBounds(Size size)
 
         private protected sealed override void HandleClosed()
         {
-            RaiseEvent(new RoutedEventArgs(WindowClosedEvent));
+            _shown = false;
 
             base.HandleClosed();
 
+            RaiseEvent(new RoutedEventArgs(WindowClosedEvent));
+
             Owner = null;
         }
 

tests/Avalonia.Controls.UnitTests/DesktopStyleApplicationLifetimeTests.cs

@@ -126,6 +126,86 @@ public void Should_Exit_After_MainWindow_Closed()
             }
         }
 
+        [Fact]
+        public void OnMainWindowClose_Overrides_Secondary_Window_Cancellation()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
+            {
+                lifetime.ShutdownMode = ShutdownMode.OnMainWindowClose;
+                lifetime.SetupCore(Array.Empty<string>());
+
+                var hasExit = false;
+                var secondaryWindowClosingExecuted = false;
+                var secondaryWindowClosedExecuted = false;
+
+                lifetime.Exit += (_, _) => hasExit = true;
+
+                var mainWindow = new Window();
+                mainWindow.Show();
+
+                lifetime.MainWindow = mainWindow;
+
+                var window = new Window();
+                window.Closing += (_, args) =>
+                {
+                    secondaryWindowClosingExecuted = true;
+                    args.Cancel = true;
+                };
+                window.Closed += (_, _) =>
+                {
+                    secondaryWindowClosedExecuted = true;
+                };
+                window.Show();
+
+                mainWindow.Close();
+
+                Assert.True(secondaryWindowClosingExecuted);
+                Assert.True(secondaryWindowClosedExecuted);
+                Assert.True(hasExit);
+            }
+        }
+
+        [Fact]
+        public void OnMainWindowClose_Overrides_Secondary_Window_Cancellation_From_TryShutdown()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime())
+            {
+                lifetime.ShutdownMode = ShutdownMode.OnMainWindowClose;
+                lifetime.SetupCore(Array.Empty<string>());
+
+                var hasExit = false;
+                var secondaryWindowClosingExecuted = false;
+                var secondaryWindowClosedExecuted = false;
+
+                lifetime.Exit += (_, _) => hasExit = true;
+
+                var mainWindow = new Window();
+                mainWindow.Show();
+
+                lifetime.MainWindow = mainWindow;
+
+                var window = new Window();
+                window.Closing += (_, args) =>
+                {
+                    secondaryWindowClosingExecuted = true;
+                    args.Cancel = true;
+                };
+                window.Closed += (_, _) =>
+                {
+                    secondaryWindowClosedExecuted = true;
+                };
+                window.Show();
+
+                lifetime.TryShutdown();
+
+                Assert.True(secondaryWindowClosingExecuted);
+                Assert.True(secondaryWindowClosedExecuted);
+                Assert.True(hasExit);
+            }
+        }
+
         [Fact]
         public void Should_Exit_After_Last_Window_Closed()
         {
@@ -401,6 +481,8 @@ public void Shutdown_NotCancellable_By_Preventing_Window_Close()
                 lifetime.SetupCore(Array.Empty<string>());
 
                 var hasExit = false;
+                var closingRaised = 0;
+                var closedRaised = 0;
 
                 lifetime.Exit += (_, _) => hasExit = true;
 
@@ -411,18 +493,21 @@ public void Shutdown_NotCancellable_By_Preventing_Window_Close()
                 var windowB = new Window();
 
                 windowB.Show();
-
-                var raised = 0;
 
                 windowA.Closing += (_, e) =>
                 {
                     e.Cancel = true;
-                    ++raised;
+                    ++closingRaised;
+                };
+                windowA.Closed += (_, e) =>
+                {
+                    ++closedRaised;
                 };
 
                 lifetime.Shutdown();
 
-                Assert.Equal(1, raised);
+                Assert.Equal(1, closingRaised);
+                Assert.Equal(1, closedRaised);
                 Assert.True(hasExit);
             }
         }

tests/Avalonia.Controls.UnitTests/WindowTests.cs

@@ -112,6 +112,8 @@ public void IsVisible_Should_Be_False_After_Impl_Signals_Close()
                 var window = new Window();
 
                 window.Show();
+                Assert.True(window.IsVisible);
+
                 windowImpl.Object.Closed();
 
                 Assert.False(window.IsVisible);