[iOS] Allow Forms gestures on custom renderers for controls which already have gestures (#990)

* Repro 57114 with UI test; fix for 57114 on iOS

* Repro/UI test for Windows

* Add helpful comment for posterity

* Remove stray TODO

* Only do ShouldReceiveTouch on mobile

* Explicitly require wrapped UIView to have gesture recognizers

2 files changed, 111 insertions, 0 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla57114.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla57114.cs
new file mode 100644
index 00000000..353939ea
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla57114.cs
@@ -0,0 +1,110 @@
+using System;
+using System.Diagnostics;
+
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.Forms.Core.UITests;
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.Gestures)]
+#endif
+
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 57114, "Forms gestures are not supported on UIViews that have native gestures", PlatformAffected.iOS)]
+	public class Bugzilla57114 : TestContentPage
+	{
+		public static string _57114NativeGestureFiredMessage = "_57114NativeGestureFiredMessage";
+
+		Label _results;
+		bool _nativeGestureFired;
+		bool _formsGestureFired;
+
+		const string Testing = "Testing...";
+		const string Success = "Success";
+		const string AutomationId = "_57114View";
+
+		protected override void Init()
+		{
+			var instructions = new Label
+			{
+				Text = $"Tap the Aqua View below. If the label below changes from '{Testing}' to '{Success}', the test has passed."
+			};
+
+			_results = new Label { Text = Testing };
+
+			var view = new _57114View
+			{
+				AutomationId = AutomationId,
+				HeightRequest = 200, WidthRequest = 200,
+				BackgroundColor = Color.Aqua,
+				HorizontalOptions = LayoutOptions.Fill,
+				VerticalOptions = LayoutOptions.Fill
+			};
+
+			var tap = new TapGestureRecognizer
+			{
+				Command = new Command(() =>
+				{
+					_formsGestureFired = true;
+					UpdateResults();
+				})
+			};
+
+			MessagingCenter.Subscribe<object>(this, _57114NativeGestureFiredMessage, NativeGestureFired);
+
+			view.GestureRecognizers.Add(tap);
+
+			var layout = new StackLayout()
+			{
+				HorizontalOptions = LayoutOptions.Fill,
+				VerticalOptions = LayoutOptions.Fill,
+				Children =
+				{
+					instructions, _results, view
+				}
+			};
+
+			Content = layout;
+		}
+
+		void NativeGestureFired(object obj)
+		{
+			_nativeGestureFired = true;
+			UpdateResults();
+		}
+
+		void UpdateResults()
+		{
+			if (_nativeGestureFired && _formsGestureFired)
+			{
+				_results.Text = Success;
+			}
+			else
+			{
+				_results.Text = Testing;
+			}
+		}
+
+		[Preserve(AllMembers = true)]
+		public class _57114View : View
+		{
+		}
+
+#if UITEST
+		[Test]
+		public void _57114BothTypesOfGesturesFire()
+		{
+			RunningApp.WaitForElement(Testing);
+			RunningApp.Tap(AutomationId);
+			RunningApp.WaitForElement(Success);
+		}
+#endif
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index 97f26f7f..62b97166 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -208,6 +208,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla56609.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla55912.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla57317.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla57114.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)CarouselAsync.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34561.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34727.cs" />