[Windows] Fixed StackLayout crashes on Windows with HeightRequest as 0

src/Controls/tests/TestCases.HostApp/Issues/Issue29919.cs

@@ -0,0 +1,35 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 29919, "StackLayout Throws Exception on Windows When Orientation Is Set with HeightRequest of 0, Padding, and Opposing Alignment", PlatformAffected.UWP)]
+public class Issue29919 : ContentPage
+{
+    public Issue29919()
+    {
+		var stack = new StackLayout();
+		var label = new Label
+		{
+			Text = "VerticalStackLayout and HorizontalStackLayout should not crash when WidthRequest or HeightRequest is explicitly set to 0, respectively.",
+			AutomationId = "29919DescriptionLabel",
+		};
+
+        var horizontalStack = new HorizontalStackLayout
+        {
+            Padding = new Thickness(5),
+            HeightRequest = 0,
+            VerticalOptions = LayoutOptions.Center
+        };
+
+		var verticalStack = new VerticalStackLayout
+		{
+			Padding = new Thickness(5),
+			WidthRequest = 0,
+			HeightRequest = 100,
+			HorizontalOptions = LayoutOptions.Center
+		};
+
+		stack.Children.Add(label);
+		stack.Children.Add(horizontalStack);
+		stack.Children.Add(verticalStack);
+		Content = stack;
+    }
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue29919.cs

@@ -0,0 +1,21 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue29919 : _IssuesUITest
+{
+    public Issue29919(TestDevice testDevice) : base(testDevice)
+    {
+    }
+
+    public override string Issue => "StackLayout Throws Exception on Windows When Orientation Is Set with HeightRequest of 0, Padding, and Opposing Alignment";
+
+    [Test]
+    [Category(UITestCategories.Layout)]
+    public void StackLayoutWindowsCrashWithZeroHeight()
+    {
+        App.WaitForElement("29919DescriptionLabel");
+    }
+}

src/Core/src/Layouts/HorizontalStackLayoutManager.cs

@@ -50,7 +50,7 @@ public override Size ArrangeChildren(Rect bounds)
 
 			double top = padding.Top + bounds.Top;
 
-			var height = bounds.Height - padding.VerticalThickness;
+			var height = Math.Max(0, bounds.Height - padding.VerticalThickness);
 
 			// Figure out where we're starting from 
 			double xPosition = padding.Left + bounds.Left;

src/Core/src/Layouts/VerticalStackLayoutManager.cs

@@ -49,7 +49,7 @@ public override Size ArrangeChildren(Rect bounds)
 
 			double stackHeight = padding.Top + bounds.Y;
 			double left = padding.Left + bounds.X;
-			double width = bounds.Width - padding.HorizontalThickness;
+			double width = Math.Max(0, bounds.Width - padding.HorizontalThickness);
 
 			for (int n = 0; n < Stack.Count; n++)
 			{