[Core] Fixes '0*' RowDefinition/ColumnDefinition in Grid (#2926) fixes #2767

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue2767.cs

@@ -0,0 +1,51 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 2767, "ArgumentException: NaN not valid for height", PlatformAffected.All)]
+	public class Issue2767 : TestContentPage
+	{
+		protected override void Init()
+		{
+			var grid = new Grid
+			{
+				RowDefinitions =
+				{
+					new RowDefinition { Height = new GridLength(0, GridUnitType.Star) },
+					new RowDefinition { Height = new GridLength(60, GridUnitType.Star) },
+				},
+				ColumnDefinitions =
+				{
+					new ColumnDefinition { Width = new GridLength(0, GridUnitType.Star) },
+					new ColumnDefinition { Width = new GridLength(10, GridUnitType.Star) },
+				}
+			};
+			grid.AddChild(new Label { Text = "Collapsed" }, 0, 0);
+			grid.AddChild(new Label { Text = "Collapsed" }, 0, 1);
+			grid.AddChild(new Label { Text = "Collapsed" }, 1, 0);
+			grid.AddChild(new Label { Text = "Label 1:1" }, 1, 1);
+			
+			Content = new Frame
+			{
+				HorizontalOptions = LayoutOptions.CenterAndExpand,
+				Content = grid
+			};
+		}
+
+#if UITEST
+		[Test]
+		public void Issue2767Test()
+		{
+			RunningApp.WaitForElement("Label 1:1");
+			Assert.IsEmpty(RunningApp.Query("Collapsed"));
+		}
+#endif
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -239,6 +239,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla59580.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Effects\AttachedStateEffect.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Effects\AttachedStateEffectList.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue2767.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)GitHub1878.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Helpers\ISampleNativeControl.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Helpers\ViewHelper.cs" />

Xamarin.Forms.Core/GridCalc.cs

@@ -468,7 +468,7 @@ namespace Xamarin.Forms
 				ColumnDefinition col = _columns[index];
 				if (!col.Width.IsStar)
 					continue;
-				starColWidth = Math.Max(starColWidth, col.ActualWidth / col.Width.Value);
+				starColWidth = col.Width.Value != 0 ? Math.Max(starColWidth, col.ActualWidth / col.Width.Value) : 0;
 			}
 
 			return starColWidth;
@@ -567,7 +567,7 @@ namespace Xamarin.Forms
 				RowDefinition row = _rows[index];
 				if (!row.Height.IsStar)
 					continue;
-				starRowHeight = Math.Max(starRowHeight, row.ActualHeight / row.Height.Value);
+				starRowHeight = row.Height.Value != 0 ? Math.Max(starRowHeight, row.ActualHeight / row.Height.Value) : 0;
 			}
 
 			return starRowHeight;