From dc35216f410259f7da2d3babe66b7b0cfda8a5cd Mon Sep 17 00:00:00 2001
From: H1Gdev <h1g.z.ouroboros+github@gmail.com>
Date: Sat, 31 Aug 2019 23:30:02 +0900
Subject: [PATCH]  Do not copy None, Inherit and NotSet at DeepCopy  (#565)

* Do not copy None, Inherit and NotSet at DeepCopy.
* Add test.
---
 Source/Painting/SvgColourServer.cs            | 3 +++
 Tests/Svg.UnitTests/SvgElementDeepCopyTest.cs | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/Source/Painting/SvgColourServer.cs b/Source/Painting/SvgColourServer.cs
index eabb462..d38f734 100644
--- a/Source/Painting/SvgColourServer.cs
+++ b/Source/Painting/SvgColourServer.cs
@@ -73,6 +73,9 @@ namespace Svg
 
         public override SvgElement DeepCopy<T>()
         {
+            if (this == None || this == Inherit || this == NotSet)
+                return this;
+
             var newObj = base.DeepCopy<T>() as SvgColourServer;
             newObj.Colour = this.Colour;
             return newObj;
diff --git a/Tests/Svg.UnitTests/SvgElementDeepCopyTest.cs b/Tests/Svg.UnitTests/SvgElementDeepCopyTest.cs
index 9a9f350..6ab3540 100644
--- a/Tests/Svg.UnitTests/SvgElementDeepCopyTest.cs
+++ b/Tests/Svg.UnitTests/SvgElementDeepCopyTest.cs
@@ -71,6 +71,14 @@ namespace Svg.UnitTests
             Assert.IsInstanceOf<T>(dest);
         }
 
+        [Test]
+        public void TestDoNotDeepCopy()
+        {
+            Assert.AreSame(SvgPaintServer.None, SvgPaintServer.None.DeepCopy());
+            Assert.AreSame(SvgColourServer.Inherit, SvgColourServer.Inherit.DeepCopy());
+            Assert.AreSame(SvgColourServer.NotSet, SvgColourServer.NotSet.DeepCopy());
+        }
+
         /// <summary>
         /// Tests that the deep copy of a <see cref="SvgText"/> is done correctly where the
         /// text element has contains only text and now other elements like <see cref="SvgTextSpan"/>.