Fix Entry issue using TextColor and ClearButton in iOS < 13 (#14566)

Co-authored-by: Gerald Versluis <gerald.versluis@microsoft.com>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue14523.xaml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<local:TestContentPage
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:d="http://xamarin.com/schemas/2014/forms/design"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Title="Test 14523" xmlns:local="using:Xamarin.Forms.Controls"
+    x:Class="Xamarin.Forms.Controls.Issues.Issue14523">
+    <StackLayout>
+        <Label
+            Padding="12"
+            BackgroundColor="Black"
+            TextColor="White"
+            Text="Without exceptions, the test has passed."/>
+        <Entry 
+            ClearButtonVisibility="WhileEditing"
+            TextColor="Red" />
+    </StackLayout>
+</local:TestContentPage>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue14523.xaml.cs

@@ -0,0 +1,35 @@
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Windows.Input;
+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.CarouselView)]
+#endif
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 14523,
+		"[Bug] NullReferenceException in EntryRenderer on iOS versions <14.X with ClearButtonVisibility.WhileEditing and non-default TextColor",
+		PlatformAffected.iOS)]
+	public partial class Issue14523 : TestContentPage
+	{
+		public Issue14523()
+		{
+#if APP
+			InitializeComponent();
+#endif
+		}
+
+		protected override void Init()
+		{
+		}
+	}
+}

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

@@ -23,6 +23,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue13551.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13819.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13916.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue14523.xaml.cs">
+      <DependentUpon>Issue14523.xaml</DependentUpon>
+    </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Issue14428.xaml.cs">
       <DependentUpon>Issue14428.xaml</DependentUpon>
     </Compile>
@@ -2755,6 +2758,10 @@
     </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue14523.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue14428.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>

Xamarin.Forms.Platform.iOS/Renderers/EntryRenderer.cs

@@ -571,7 +571,7 @@ void UpdateClearButtonColor()
 				if(_defaultClearImage == null)
 					_defaultClearImage = clearButton.ImageForState(UIControlState.Highlighted);
 
-				if(Element.TextColor == Color.Default)
+				if (Element.TextColor == Color.Default)
 				{
 					clearButton.SetImage(_defaultClearImage, UIControlState.Normal);
 					clearButton.SetImage(_defaultClearImage, UIControlState.Highlighted);
@@ -580,14 +580,20 @@ void UpdateClearButtonColor()
 				{
 					var tintedClearImage = GetClearButtonTintImage(_defaultClearImage, Element.TextColor.ToUIColor());
 
-					clearButton.SetImage(tintedClearImage, UIControlState.Normal);
-					clearButton.SetImage(tintedClearImage, UIControlState.Highlighted);
+					if (tintedClearImage != null)
+					{
+						clearButton.SetImage(tintedClearImage, UIControlState.Normal);
+						clearButton.SetImage(tintedClearImage, UIControlState.Highlighted);
+					}
 				}
 			}
 		}
 
 		UIImage GetClearButtonTintImage(UIImage image, UIColor color)
 		{
+			if (image == null)
+				return null;
+
 			var size = image.Size;
 
 			UIGraphics.BeginImageContextWithOptions(size, false, UIScreen.MainScreen.Scale);