Shell - Propagate BackButtonBehaviorProperty (#28615)

* Propagate BackButtonBehaviorProperty

* Added a UITest

Author: kubaflo

src/Controls/src/Core/Internals/PropertyPropagationExtensions.cs

@@ -40,6 +40,9 @@ internal static void PropagatePropertyChanged(string propertyName, Element eleme
 
 			if (propertyName == null || propertyName == Shell.NavBarVisibilityAnimationEnabledProperty.PropertyName)
 				BaseShellItem.PropagateFromParent(Shell.NavBarVisibilityAnimationEnabledProperty, element);
+				
+			if (propertyName == null || propertyName == Shell.BackButtonBehaviorProperty.PropertyName)
+				BaseShellItem.PropagateFromParent(Shell.BackButtonBehaviorProperty, element);
 
 			foreach (var child in children.ToArray())
 			{

src/Controls/tests/TestCases.HostApp/Issues/Issue28570.cs

@@ -0,0 +1,56 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 28570, "Setting BackButtonBehavior to not visible or not enabled does not work")]
+public class Issue28570 : Shell
+{
+	public Issue28570()
+	{
+		// Register the routes
+		Routing.RegisterRoute("Issue28570DetailPage", typeof(Issue28570DetailPage));
+
+		ContentPage contentPage = new ContentPage
+		{
+			Title = "Main Page",
+			Content = new Button
+			{
+				Text = "Go to Detail Page",
+				AutomationId = "NavigateToDetailButton",
+				Command = new Command(async () => await Shell.Current.GoToAsync("Issue28570DetailPage"))
+			}
+		};
+
+		BackButtonBehavior backButtonBehavior = new BackButtonBehavior
+		{
+			IsVisible = false,
+			TextOverride = "BackButton"
+		};
+
+		SetBackButtonBehavior(this, backButtonBehavior);
+
+		// Create and add Shell contents
+		var page1 = new ShellContent
+		{
+			Title = "Page 1",
+			Content = contentPage
+		};
+
+		Items.Add(page1);
+	}
+}
+
+public class Issue28570DetailPage : ContentPage
+{
+	public Issue28570DetailPage()
+	{
+		Title = "Detail page";
+
+		Content = new VerticalStackLayout()
+		{
+			new Label()
+			{
+				AutomationId = "HelloLabel",
+				Text = "Hello, from the detail page",
+			}
+		};
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28570.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue28570 : _IssuesUITest
+{
+	public Issue28570(TestDevice testDevice) : base(testDevice) { }
+
+	public override string Issue => "Setting BackButtonBehavior to not visible or not enabled does not work";
+
+	[Test]
+	[Category(UITestCategories.Shell)]
+	[Category(UITestCategories.Navigation)]
+	public void BackButtonShouldNotBeVisible()
+	{
+		App.WaitForElement("NavigateToDetailButton");
+		App.Click("NavigateToDetailButton");
+		App.WaitForElement("HelloLabel");
+		App.WaitForNoElement("BackButton");
+	}
+}