report file location on error (#6024)

Xamarin.Forms.Core/Internals/ResourceLoader.cs

@@ -54,6 +54,17 @@ namespace Xamarin.Forms.Internals
 			public bool UseDesignProperties { get; set; }
 		}
 
-		internal static Action<Exception> ExceptionHandler { get; set; }
+		static Action<Exception> exceptionHandler1;
+
+		[Obsolete("2 is better than 1")]
+		internal static Action<Exception> ExceptionHandler {
+			get => exceptionHandler1;
+			set {
+				exceptionHandler1 = value;
+				ExceptionHandler2 = value != null ? ((Exception exception, string filepath) err) => exceptionHandler1(err.exception) : (Action<(Exception, string)>)null;
+			}
+		}
+
+		internal static Action<(Exception exception, string filepath)> ExceptionHandler2 { get; set; }
 	}
-}
+}

Xamarin.Forms.Core/NameScopeExtensions.cs

@@ -10,8 +10,8 @@ namespace Xamarin.Forms
 			try {
 				return (T)element.FindByName(name);
 			}
-			catch (InvalidCastException ice) when (ResourceLoader.ExceptionHandler != null) {
-				ResourceLoader.ExceptionHandler(ice);
+			catch (InvalidCastException ice) when (ResourceLoader.ExceptionHandler2 != null) {
+				ResourceLoader.ExceptionHandler2((ice, null));
 				return default(T);
 			}
 		}

Xamarin.Forms.Xaml.UnitTests/DesignTimeLoaderTests.cs

@@ -23,8 +23,8 @@ namespace Xamarin.Forms.Xaml.UnitTests
 			XamlLoader.FallbackTypeResolver = null;
 			XamlLoader.ValueCreatedCallback = null;
 			XamlLoader.InstantiationFailedCallback = null;
-			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = null;
 #pragma warning disable 0618
+			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = null;
 			Xamarin.Forms.Xaml.Internals.XamlLoader.DoNotThrowOnExceptions = false;
 #pragma warning restore 0618
 		}
@@ -365,7 +365,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 				</ContentPage>";
 
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 
 			var page = (ContentPage)XamlLoader.Create(xaml, true);
 			Assert.That(page.Content, Is.TypeOf<Button>());
@@ -533,7 +535,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 					</ContentPage>";
 
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 			Assert.DoesNotThrow(() => XamlLoader.Create(xaml, true));
 			Assert.That(exceptions.Count, Is.EqualTo(2));
 		}
@@ -549,7 +553,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 					</ContentPage>";
 
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 			Assert.DoesNotThrow(() => XamlLoader.Create(xaml, true));
 			Assert.That(exceptions.Count, Is.EqualTo(1));
 		}
@@ -568,7 +574,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 								</StackLayout>
 						</ContentPage>";
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 			Assert.DoesNotThrow(() => XamlLoader.Create(xaml, true));
 			Assert.That(exceptions.Count, Is.GreaterThan(1));
 		}
@@ -641,7 +649,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 						</StackLayout>
 					</ContentPage>";
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 			Assert.DoesNotThrow(() => XamlLoader.Create(xaml, true));
 			Assert.That(exceptions.Count, Is.GreaterThan(1));
 		}
@@ -656,7 +666,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 						</ContentPage>";
 
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 			var content = (ContentPage)XamlLoader.Create(xaml, true);
 			Assert.DoesNotThrow(() => content.FindByName<Button>("MyName"));
 			Assert.That(exceptions.Count, Is.GreaterThanOrEqualTo(1));
@@ -677,7 +689,9 @@ namespace Xamarin.Forms.Xaml.UnitTests
 						</ContentPage>";
 			XamlLoader.Create(xaml, true);
 			var exceptions = new List<Exception>();
+#pragma warning disable CS0618 // Type or member is obsolete
 			Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = exceptions.Add;
+#pragma warning restore CS0618 // Type or member is obsolete
 			Assert.DoesNotThrow(() => XamlLoader.Create(xaml, true));
 			Assert.That(exceptions.Count, Is.GreaterThanOrEqualTo(1));
 		}

Xamarin.Forms.Xaml.UnitTests/XStaticException.xaml.cs

@@ -35,8 +35,8 @@ namespace Xamarin.Forms.Xaml.UnitTests
 				Device.PlatformServices = new MockPlatformServices();
 
 				//there's a test not resetting the values correctly, but can't find which one...
-				Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = null;
 #pragma warning disable 0618
+				Xamarin.Forms.Internals.ResourceLoader.ExceptionHandler = null;
 				Xamarin.Forms.Xaml.Internals.XamlLoader.DoNotThrowOnExceptions = false;
 #pragma warning restore 0618
 			}

Xamarin.Forms.Xaml/XamlFilePathAttribute.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Linq;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 
 namespace Xamarin.Forms.Xaml
@@ -6,8 +8,10 @@ namespace Xamarin.Forms.Xaml
 	[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
 	public sealed class XamlFilePathAttribute : Attribute
 	{
-		public XamlFilePathAttribute([CallerFilePath] string filePath = "")
-		{
-		}
+		public XamlFilePathAttribute([CallerFilePath] string filePath = "") => FilePath = filePath;
+
+		public string FilePath { get; }
+
+		internal static string GetFilePathForObject(object view) => (view?.GetType().GetTypeInfo().GetCustomAttributes(typeof(XamlFilePathAttribute), false).FirstOrDefault() as XamlFilePathAttribute)?.FilePath;
 	}
 }

Xamarin.Forms.Xaml/XamlLoader.cs

@@ -88,11 +88,14 @@ namespace Xamarin.Forms.Xaml
 
 					var rootnode = new RuntimeRootNode(new XmlType(reader.NamespaceURI, reader.Name, null), view, (IXmlNamespaceResolver)reader);
 					XamlParser.ParseXaml(rootnode, reader);
+#pragma warning disable 0618
+					var doNotThrow = ResourceLoader.ExceptionHandler2 != null || Internals.XamlLoader.DoNotThrowOnExceptions;
+#pragma warning restore 0618
+					void ehandler(Exception e) => ResourceLoader.ExceptionHandler2?.Invoke((e, XamlFilePathAttribute.GetFilePathForObject(view)));
 					Visit(rootnode, new HydrationContext {
 						RootElement = view,
-#pragma warning disable 0618
-						ExceptionHandler = ResourceLoader.ExceptionHandler ?? (Internals.XamlLoader.DoNotThrowOnExceptions ? e => { } : (Action<Exception>)null)
-#pragma warning restore 0618
+
+						ExceptionHandler = doNotThrow ? ehandler : (Action<Exception>)null
 					}, useDesignProperties);
 					break;
 				}
@@ -103,8 +106,9 @@ namespace Xamarin.Forms.Xaml
 
 		public static object Create(string xaml, bool doNotThrow, bool useDesignProperties)
 		{
-			doNotThrow = doNotThrow || ResourceLoader.ExceptionHandler != null;
-			var exceptionHandler = doNotThrow ? (ResourceLoader.ExceptionHandler ?? (e => { })) : null;
+			doNotThrow = doNotThrow || ResourceLoader.ExceptionHandler2 != null;
+			void ehandler(Exception e) => ResourceLoader.ExceptionHandler2?.Invoke((e, null));
+
 			object inflatedView = null;
 			using (var textreader = new StringReader(xaml))
 			using (var reader = XmlReader.Create(textreader)) {
@@ -123,7 +127,7 @@ namespace Xamarin.Forms.Xaml
 					var rootnode = new RuntimeRootNode(new XmlType(reader.NamespaceURI, reader.Name, typeArguments), null, (IXmlNamespaceResolver)reader);
 					XamlParser.ParseXaml(rootnode, reader);
 					var visitorContext = new HydrationContext {
-						ExceptionHandler = exceptionHandler,
+						ExceptionHandler = doNotThrow ? ehandler : (Action<Exception>)null,
 					};
 					var cvv = new CreateValuesVisitor(visitorContext);
 					cvv.Visit((ElementNode)rootnode, null);