[Android] Handle fragment removal inside of the RemovePage method (#1053)

* Repro

* Handle fragment removal inside of RemovePage method

* Fix class name for test

* Split long strings

2 files changed, 87 insertions, 0 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/PopAfterRemove.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/PopAfterRemove.cs
new file mode 100644
index 00000000..c7508fbd
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/PopAfterRemove.cs
@@ -0,0 +1,86 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.Navigation)]
+#endif
+
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.None, 0101100101, 
+		"PopAsync crashing after RemovePage when support packages are updated to 25.1.1",
+		PlatformAffected.Android)]
+	public class PopAfterRemove : TestNavigationPage
+	{
+		ContentPage _intermediate1;
+		ContentPage _intermediate2;
+
+		protected override async void Init()
+		{
+			_intermediate1 = Intermediate();
+			_intermediate2 = Intermediate();
+
+			await PushAsync(Root());
+			await PushAsync(_intermediate1);
+			await PushAsync(_intermediate2);
+			await PushAsync(Last());
+		}
+
+		const string StartTest = "Start Test";
+		const string RootLabel = "Root";
+
+		ContentPage Last()
+		{
+			var test = new Button { Text = StartTest };
+
+			var instructions = new Label
+			{
+				Text =
+					$"Tap the button labeled '{StartTest}'. The app should navigate to a page displaying the label " 
+					+ $"'{RootLabel}'. If the application crashes, the test has failed."
+			};
+
+			var layout = new StackLayout();
+
+			layout.Children.Add(instructions);
+			layout.Children.Add(test);
+
+			test.Clicked += (sender, args) =>
+			{
+				Navigation.RemovePage(_intermediate2);
+				Navigation.RemovePage(_intermediate1);
+				
+				Navigation.PopAsync(true);
+			};
+
+			return new ContentPage { Content = layout };
+		}
+
+		static ContentPage Root()
+		{
+			return new ContentPage { Content = new Label { Text = RootLabel } };
+		}
+
+		static ContentPage Intermediate()
+		{
+			return new ContentPage { Content = new Label { Text = "Page" } };
+		}
+
+#if UITEST
+		[Test]
+		public void PopAsyncAfterRemovePageDoesNotCrash()
+		{
+			RunningApp.WaitForElement(StartTest);
+			RunningApp.Tap(StartTest);
+			RunningApp.WaitForElement(RootLabel);
+		}
+#endif
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index b4155f62..04954748 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -271,6 +271,7 @@
       <DependentUpon>PlatformSpecifics_iOSTranslucentNavBarX.xaml</DependentUpon>
       <SubType>Code</SubType>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)PopAfterRemove.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)TestPages\ScreenshotConditionalApp.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41842.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42277.cs" />