From fe47e42e7dfb5a09d10f74075701cd974c0f723d Mon Sep 17 00:00:00 2001
From: jnm2 <me@jnm2.com>
Date: Thu, 2 Jan 2020 22:11:13 -0500
Subject: [PATCH 1/2] Skip copying documentation file when target already
 exists

---
 .../AnnotatorBuildTask.cs                           |  9 ++++++++-
 .../WindowsErrorCode.cs                             | 13 +++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 TunnelVisionLabs.ReferenceAssemblyAnnotator/WindowsErrorCode.cs

diff --git a/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs b/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs
index 20f6c71..3258d0e 100644
--- a/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs
+++ b/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs
@@ -104,7 +104,14 @@ public override bool Execute()
             string targetDocumentation = Path.ChangeExtension(outputAssembly, ".xml");
             if (File.Exists(sourceDocumentation))
             {
-                File.Copy(sourceDocumentation, targetDocumentation);
+                try
+                {
+                    File.Copy(sourceDocumentation, targetDocumentation);
+                }
+                catch (IOException ex) when ((WindowsErrorCode)ex.HResult == WindowsErrorCode.FileExists)
+                {
+                }
+
                 GeneratedDocumentationFiles = new[] { new TaskItem(targetDocumentation) };
             }
             else
diff --git a/TunnelVisionLabs.ReferenceAssemblyAnnotator/WindowsErrorCode.cs b/TunnelVisionLabs.ReferenceAssemblyAnnotator/WindowsErrorCode.cs
new file mode 100644
index 0000000..64e8d7d
--- /dev/null
+++ b/TunnelVisionLabs.ReferenceAssemblyAnnotator/WindowsErrorCode.cs
@@ -0,0 +1,13 @@
+// Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+namespace TunnelVisionLabs.ReferenceAssemblyAnnotator
+{
+    internal enum WindowsErrorCode : ushort
+    {
+        /// <summary>
+        /// https://docs.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499-#error_file_exists
+        /// </summary>
+        FileExists = 80,
+    }
+}

From 890b1174b6546b3373c734c45d231f3b1289b753 Mon Sep 17 00:00:00 2001
From: Joseph Musser <me@jnm2.com>
Date: Fri, 3 Jan 2020 13:11:52 -0500
Subject: [PATCH 2/2] Avoid letting an exception be thrown when possible

Co-Authored-By: Sam Harwell <sam@tunnelvisionlabs.com>
---
 .../AnnotatorBuildTask.cs                                       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs b/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs
index 3258d0e..04bbdb6 100644
--- a/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs
+++ b/TunnelVisionLabs.ReferenceAssemblyAnnotator/AnnotatorBuildTask.cs
@@ -102,7 +102,7 @@ public override bool Execute()
 
             string sourceDocumentation = Path.ChangeExtension(unannotatedReferenceAssembly, ".xml");
             string targetDocumentation = Path.ChangeExtension(outputAssembly, ".xml");
-            if (File.Exists(sourceDocumentation))
+            if (File.Exists(sourceDocumentation) && !File.Exists(targetDocumentation))
             {
                 try
                 {