Add Support for Popups inside a Modal NavigationPage

src/CommunityToolkit.Maui.UnitTests/Views/Popup/PopupPageTests.cs

@@ -296,6 +296,45 @@ void HandlePopupPageClosed(object? sender, IPopupResult e)
 		}
 	}
 
+	[Fact]
+	public async Task ShowPopupAsync_FromModalNavigationPage_ShouldCloseSuccessfully()
+	{
+		// Remove shell navigation
+		var rootPage = new ContentPage { Title = "Root" };
+
+		if (Application.Current is null)
+		{
+			throw new InvalidOperationException("Application.Current is null. Unable to set the root page.");
+		}
+
+		if (Application.Current.Windows.Count == 0)
+		{
+			throw new InvalidOperationException("No application windows found. Unable to set the root page.");
+		}
+
+		Application.Current.Windows[0].Page = rootPage;
+		var modalNavigationPage = new NavigationPage(new ContentPage { Title = "Modal Navigation Page" });
+		var popup = new Popup<string>();
+
+		// Act - Push modal navigation page
+		await rootPage.Navigation.PushModalAsync(modalNavigationPage, false);
+
+		// Assert - Verify modal stack has the modal navigation page
+		Assert.Single(rootPage.Navigation.ModalStack);
+		Assert.Same(modalNavigationPage, rootPage.Navigation.ModalStack[0]);
+
+		// Act
+		var showPopupAsyncTask = modalNavigationPage.ShowPopupAsync<string>(popup, token: TestContext.Current.CancellationToken);
+		await popup.CloseAsync("Hello", TestContext.Current.CancellationToken);
+		var result = await showPopupAsyncTask;
+
+		// Assert
+		result.Result.Should().Be("Hello");
+
+		// Cleanup
+		await rootPage.Navigation.PopModalAsync(false);
+	}
+
 	[Fact]
 	public void PopupPageT_Close_ShouldThrowOperationCanceledException_WhenTokenIsCancelled()
 	{
@@ -615,6 +654,87 @@ public async Task Close_ShouldThrowException_WhenCalledOnNonModalPopup()
 		await Assert.ThrowsAsync<PopupNotFoundException>(async () => await popupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
 	}
 
+	[Fact]
+	public async Task CloseAsync_ShouldThrowPopupBlockedException_WhenPopupIsBehindModalNavigationPage()
+	{
+		// Arrange
+		if (Application.Current?.Windows[0].Page?.Navigation is not INavigation navigation)
+		{
+			throw new InvalidOperationException("Unable to locate Navigation page");
+		}
+
+		bool wasPopupPageClosed = false;
+
+		var popupPage = new PopupPage<string>(new ContentView(), new MockPopupOptions());
+		popupPage.PopupClosed += HandlePopupPageClosed;
+
+		var modalNavigationPage = new NavigationPage(new ContentPage());
+
+		// Act
+
+		// Push popup, then push a modal NavigationPage on top
+		// Modal stack: [PopupPage, NavigationPage(ContentPage)]
+		await navigation.PushModalAsync(popupPage);
+		await navigation.PushModalAsync(modalNavigationPage);
+
+		// Assert
+
+		// When the top of the modal stack is an IPageContainer whose CurrentPage is NOT a PopupPage,
+		// CloseAsync should throw PopupBlockedException because PopModalAsync would pop the
+		// visible NavigationPage instead of the PopupPage, leaving the PopupPage stranded on the
+		// modal stack while still incorrectly firing PopupClosed/NotifyPopupIsClosed.
+		await Assert.ThrowsAsync<PopupBlockedException>(async () => await popupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
+		await Assert.ThrowsAnyAsync<InvalidPopupOperationException>(async () => await popupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
+		await Assert.ThrowsAnyAsync<InvalidOperationException>(async () => await popupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
+
+		// Verify popup was NOT closed — it should still be on the modal stack
+		Assert.False(wasPopupPageClosed);
+		Assert.Contains(popupPage, navigation.ModalStack);
+
+		void HandlePopupPageClosed(object? sender, IPopupResult e)
+		{
+			wasPopupPageClosed = true;
+			popupPage.PopupClosed -= HandlePopupPageClosed;
+		}
+	}
+
+	[Fact]
+	public async Task CloseAsync_ShouldThrowPopupBlockedException_WhenPopupIsHiddenBehindAnotherPopupAndNavigationPage()
+	{
+		// Arrange
+		if (Application.Current?.Windows[0].Page?.Navigation is not INavigation navigation)
+		{
+			throw new InvalidOperationException("Unable to locate Navigation page");
+		}
+
+		bool wasPopupPageClosed = false;
+
+		var firstPopupPage = new PopupPage<string>(new ContentView(), new MockPopupOptions());
+		firstPopupPage.PopupClosed += HandlePopupPageClosed;
+
+		var secondPopupPage = new PopupPage<string>(new Button(), new MockPopupOptions());
+		var navigationPageOnTop = new NavigationPage(new ContentPage());
+
+		// Act
+
+		// Push first popup, second popup, then NavigationPage on top
+		await navigation.PushModalAsync(firstPopupPage);
+		await navigation.PushModalAsync(secondPopupPage);
+		await navigation.PushModalAsync(navigationPageOnTop);
+
+		// Assert
+		await Assert.ThrowsAsync<PopupBlockedException>(async () => await firstPopupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
+		await Assert.ThrowsAnyAsync<InvalidPopupOperationException>(async () => await firstPopupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
+		await Assert.ThrowsAnyAsync<InvalidOperationException>(async () => await firstPopupPage.CloseAsync(new PopupResult(false), TestContext.Current.CancellationToken));
+		Assert.False(wasPopupPageClosed);
+
+		void HandlePopupPageClosed(object? sender, IPopupResult e)
+		{
+			wasPopupPageClosed = true;
+			firstPopupPage.PopupClosed -= HandlePopupPageClosed;
+		}
+	}
+
 	[Fact]
 	public void PopupPage_ShouldRespectLayoutOptions()
 	{

src/CommunityToolkit.Maui/Views/Popup/PopupPage.shared.cs

@@ -77,27 +77,37 @@ public async Task CloseAsync(PopupResult result, CancellationToken token = defau
 		token.ThrowIfCancellationRequested();
 
 		// Handle edge case where a Popup was pushed inside a custom IPageContainer (e.g. a NavigationPage) on the Modal Stack
-		var customPageContainer = Navigation.ModalStack.OfType<IPageContainer<Page>>().LastOrDefault();
-		if (customPageContainer is not null && customPageContainer.CurrentPage is not PopupPage)
+		var navigationPageOnModalStackContainingPopupPage = Navigation.ModalStack.OfType<IPageContainer<Page>>().LastOrDefault();
+		if (navigationPageOnModalStackContainingPopupPage is not null && navigationPageOnModalStackContainingPopupPage.CurrentPage is not PopupPage)
 		{
-			throw new PopupNotFoundException();
+			navigationPageOnModalStackContainingPopupPage = null;
 		}
 
-		var popupPageToClose = customPageContainer?.CurrentPage as PopupPage
+		var popupPageToClose = navigationPageOnModalStackContainingPopupPage?.CurrentPage as PopupPage
 							   ?? Navigation.ModalStack.OfType<PopupPage>().LastOrDefault()
 							   ?? throw new PopupNotFoundException();
 
 		// PopModalAsync will pop the last (top) page from the ModalStack
 		// Ensure that the PopupPage the user is attempting to close is the last (top) page on the Modal stack before calling Navigation.PopModalAsync
-		if (Navigation.ModalStack[^1] is IPageContainer<Page> { CurrentPage: PopupPage visiblePopupPageInCustomPageContainer }
-			 && visiblePopupPageInCustomPageContainer.Content != Content)
+		switch (Navigation.ModalStack[^1])
 		{
-			throw new PopupBlockedException(visiblePopupPageInCustomPageContainer);
+			// Handle the edge case where the visible modal page is a navigation page containing a Popup that is not the Popup to be closed 
+			case IPageContainer<Page> { CurrentPage: PopupPage visiblePopupPageInCustomPageContainer } when visiblePopupPageInCustomPageContainer.Content != Content:
+				throw new PopupBlockedException(visiblePopupPageInCustomPageContainer);
+
+			// Handle edge case where the top of the modal stack is an IPageContainer whose CurrentPage is NOT a PopupPage
+			// (e.g. a modal NavigationPage pushed after showing a popup).
+			case IPageContainer<Page> { CurrentPage: not PopupPage }:
+				throw new PopupBlockedException(Navigation.ModalStack[^1]);
+
+			// Handle edge case where the visible modal page is not the Popup to be closed 
+			case ContentPage currentVisibleModalPage when currentVisibleModalPage.Content != Content:
+				throw new PopupBlockedException(currentVisibleModalPage);
 		}
-		else if (Navigation.ModalStack[^1] is ContentPage currentVisibleModalPage
-				 && currentVisibleModalPage.Content != Content)
+
+		if (popupPageToClose.Content != Content)
 		{
-			throw new PopupBlockedException(currentVisibleModalPage);
+			throw new PopupBlockedException(popupPageToClose);
 		}
 
 		// We call `.ThrowIfCancellationRequested()` again to avoid a race condition where a developer cancels the CancellationToken after we check for an InvalidOperationException