Route Navigation.(Push/Pop)Modal through Shell Navigation Manager (#14080)

* Route Navigation.(Push/Pop)Modal through Shell Navigation Mananger

* - fix SO error

* Update ShellNavigationManager.cs

Xamarin.Forms.Core.UnitTests/ShellModalTests.cs

@@ -381,6 +381,55 @@ namespace Xamarin.Forms.Core.UnitTests
 			Assert.AreEqual(page.GetType(), typeof(ModalTestPage));
 		}
 
+		[Test]
+		public async Task PopModalWithDots()
+		{
+			Shell shell = new Shell();
+			shell.Items.Add(CreateShellItem());
+
+			await shell.CurrentPage.Navigation.PushModalAsync(new ContentPage());
+			await shell.CurrentPage.Navigation.PushModalAsync(new ContentPage());
+			await shell.GoToAsync("..");
+			Assert.AreEqual(1, shell.Navigation.ModalStack.Count);
+			await shell.GoToAsync("..");
+			Assert.AreEqual(0, shell.Navigation.ModalStack.Count);
+		}
+
+		[Test]
+		public async Task CanCancelGoToModalAsync()
+		{
+			TestShell shell = new TestShell();
+			shell.Items.Add(CreateShellItem());
+
+			shell.Navigating += async (_, args) =>
+			{
+				var deferral = args.GetDeferral();
+				await Task.Delay(10);
+				args.Cancel();
+				deferral.Complete();
+			};
+
+			await shell.GoToAsync("ModalTestPage");
+			Assert.AreEqual(0, shell.Navigation.ModalStack.Count);
+		}
+
+		[Test]
+		public async Task CanCancelPushModalAsync()
+		{
+			TestShell shell = new TestShell();
+
+			shell.Items.Add(CreateShellItem());
+			shell.Navigating += async (_, args) =>
+			{
+				var deferral = args.GetDeferral();
+				await Task.Delay(10);
+				args.Cancel();
+				deferral.Complete();
+			};
+
+			await shell.CurrentPage.Navigation.PushModalAsync(new ContentPage());
+			Assert.AreEqual(0, shell.Navigation.ModalStack.Count);
+		}
 
 		[QueryProperty("SomeQueryParameter", "SomeQueryParameter")]
 		public class ModalTestPageBase : ShellLifeCycleTests.LifeCyclePage

Xamarin.Forms.Core.UnitTests/ShellNavigatingTests.cs

@@ -889,14 +889,14 @@ namespace Xamarin.Forms.Core.UnitTests
 			public class NavigationImpl : NavigationProxy
 			{
 				readonly NavigationMonitoringTab _navigationMonitoringTab;
-				readonly INavigation _navigation;
+				readonly NavigationProxy _navigation;
 
 				public NavigationImpl(
 					NavigationMonitoringTab navigationMonitoringTab,
 					INavigation navigation)
 				{
 					_navigationMonitoringTab = navigationMonitoringTab;
-					_navigation = navigation;
+					_navigation = (NavigationProxy)navigation;
 				}
 
 				protected override IReadOnlyList<Page> GetModalStack() => _navigation.ModalStack;

Xamarin.Forms.Core/Routing.cs

@@ -105,6 +105,7 @@ namespace Xamarin.Forms
 
 		internal static void Clear()
 		{
+			s_implicitPageRoutes.Clear();
 			s_routes.Clear();
 		}
 

Xamarin.Forms.Core/Shell/RouteRequestBuilder.cs

@@ -74,6 +74,8 @@ namespace Xamarin.Forms
 
 			bool AddNode(BaseShellItem baseShellItem, string nextSegment)
 			{
+				_ = baseShellItem ?? throw new ArgumentNullException(nameof(baseShellItem));
+
 				if (Routing.IsUserDefined(baseShellItem.Route) && baseShellItem.Route != nextSegment)
 				{
 					return false;

Xamarin.Forms.Core/Shell/ShellNavigationManager.cs

@@ -176,7 +176,7 @@ namespace Xamarin.Forms
 
 		public void HandleNavigated(ShellNavigatedEventArgs args)
 		{
-			if (_accumulateNavigatedEvents)
+			if (AccumulateNavigatedEvents)
 			{
 				if (_accumulatedEvent == null)
 					_accumulatedEvent = args;
@@ -286,7 +286,7 @@ namespace Xamarin.Forms
 			bool canCancel,
 			bool isAnimated)
 		{
-			if (_accumulateNavigatedEvents)
+			if (AccumulateNavigatedEvents)
 				return true;
 
 			var proposedState = GetNavigationState(shellItem, shellSection, shellContent, stack, shellSection.Navigation.ModalStack);
@@ -319,7 +319,7 @@ namespace Xamarin.Forms
 			bool canCancel,
 			bool isAnimated)
 		{
-			if (_accumulateNavigatedEvents)
+			if (AccumulateNavigatedEvents)
 				return null;
 
 			var navArgs = new ShellNavigatingEventArgs(_shell.CurrentState, proposedState, source, canCancel)

Xamarin.Forms.Core/Shell/ShellSection.cs

@@ -354,7 +354,7 @@ namespace Xamarin.Forms
 						var page = GetOrCreateFromRoute(globalRoutes[i], queryData, i == globalRoutes.Count - 1, false);
 						if (IsModal(page))
 						{
-							await Navigation.PushModalAsync(page, IsNavigationAnimated(page));
+							await PushModalAsync(page, IsNavigationAnimated(page));
 							break;
 						}
 						else if (!isLast && navIndex < _navStack.Count)
@@ -409,7 +409,7 @@ namespace Xamarin.Forms
 							bool isAnimated = animate ?? IsNavigationAnimated(navStack[navStack.Count - 1]);
 							if (Navigation.ModalStack.Contains(navStack[navStack.Count - 1]))
 							{
-								await Navigation.PopModalAsync(isAnimated);
+								await PopModalAsync(isAnimated);
 							}
 							else if (Navigation.ModalStack.Count > 0)
 							{
@@ -550,7 +550,7 @@ namespace Xamarin.Forms
 
 				if (modalPage is NavigationPage np)
 				{
-					await Navigation.PushModalAsync(modalPage, isAnimated);
+					await PushModalAsync(modalPage, isAnimated);
 					activeModalNavigationPage = np;
 				}
 				else
@@ -558,7 +558,7 @@ namespace Xamarin.Forms
 					if (activeModalNavigationPage != null)
 						await activeModalNavigationPage.Navigation.PushAsync(modalPage, animate ?? IsNavigationAnimated(modalPage));
 					else
-						await Navigation.PushModalAsync(modalPage, isAnimated);
+						await PushModalAsync(modalPage, isAnimated);
 				}
 			}
 
@@ -570,6 +570,22 @@ namespace Xamarin.Forms
 			}
 		}
 
+		Task PopModalAsync(bool isAnimated)
+		{
+			if (Navigation is NavigationImpl shellSectionProxy)
+				return shellSectionProxy.PopModalInnerAsync(isAnimated);
+
+			return Navigation.PopModalAsync(isAnimated);
+		}
+
+		Task PushModalAsync(Page page, bool isAnimated)
+		{
+			if (Navigation is NavigationImpl shellSectionProxy)
+				return shellSectionProxy.PushModalInnerAsync(page, isAnimated);
+
+			return Navigation.PushModalAsync(page, isAnimated);
+		}
+
 		async Task PushStackOfPages(List<Page> pages, bool? animate)
 		{
 			for (int i = pages.Count - 1; i >= 0; i--)
@@ -852,7 +868,7 @@ namespace Xamarin.Forms
 					}
 
 					bool isAnimated = animated ?? (Shell.GetPresentationMode(pageToPop) & PresentationMode.NotAnimated) != PresentationMode.NotAnimated;
-					await Navigation.PopModalAsync(isAnimated);
+					await PopModalAsync(isAnimated);
 				}
 			}
 			finally
@@ -1089,6 +1105,52 @@ namespace Xamarin.Forms
 				return _owner.Shell.NavigationManager.GoToAsync(navigationParameters);
 			}
 
+			// This is used when we just want to process the modal operation and we don't need
+			// it to process through the internal shell navigation bits
+			internal Task PushModalInnerAsync(Page modal, bool animated)
+			{
+				return Inner?.PushModalAsync(modal, animated);
+			}
+
+			// This is used when we just want to process the modal operation and we don't need
+			// it to process through the internal shell navigation bits
+			internal Task<Page> PopModalInnerAsync(bool animated)
+			{
+				return Inner?.PopModalAsync(animated);
+			}
+
+			protected override async Task OnPushModal(Page modal, bool animated)
+			{
+				if (_owner.Shell.NavigationManager.AccumulateNavigatedEvents)
+				{
+					await base.OnPushModal(modal, animated);
+					return;
+				}
+
+				if (animated)
+					Shell.SetPresentationMode(modal, PresentationMode.ModalAnimated);
+				else
+					Shell.SetPresentationMode(modal, PresentationMode.ModalNotAnimated);
+
+				var navigationParameters = new ShellNavigationParameters()
+				{
+					Animated = animated,
+					PagePushing = modal
+				};
+
+				await _owner.Shell.NavigationManager.GoToAsync(navigationParameters);
+			}
+
+			protected async override Task<Page> OnPopModal(bool animated)
+			{
+				if (_owner.Shell.NavigationManager.AccumulateNavigatedEvents)
+					return await base.OnPopModal(animated);
+
+				var page = ModalStack[ModalStack.Count - 1];
+				await _owner.Shell.GoToAsync("..", animated);
+				return page;
+			}
+      
 			protected override void OnRemovePage(Page page)
 			{
 				if (!_owner.IsVisibleSection || _owner.Shell.NavigationManager.AccumulateNavigatedEvents)
@@ -1149,4 +1211,4 @@ namespace Xamarin.Forms
 			}
 		}
 	}
-}
+}

Xamarin.Forms.Core/Shell/ShellUriHandler.cs

@@ -284,12 +284,16 @@ namespace Xamarin.Forms
 					continue;
 
 				var url = possibleRoutePath.PathFull;
+				var currentLocation = possibleRoutePath.GetNodeLocation();
+
+				if (currentLocation.Content == null)
+					continue;
 
 				var globalRouteMatches =
 					SearchForGlobalRoutes(
 						possibleRoutePath.RemainingSegments,
 						new ShellNavigationState(url, false).FullLocation,
-						possibleRoutePath.GetNodeLocation(),
+						currentLocation,
 						routeKeys);
 
 				if (globalRouteMatches.Count != 1)