From 201e9e124f84369b42ed16fa622be430e34cb618 Mon Sep 17 00:00:00 2001
From: Jan Jones <janjones@microsoft.com>
Date: Thu, 18 Jul 2024 14:03:06 +0200
Subject: [PATCH] Avoid UsingTask when the target does not exist

---
 .../targets/Microsoft.NET.Sdk.targets                     | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
index 11553b16df38..e713fe096c38 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
@@ -232,9 +232,11 @@ Copyright (c) .NET Foundation. All rights reserved.
   </PropertyGroup>
 
   <!-- NOTE: Keep in sync with https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.Common.tasks -->
-  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.CopyRefAssembly" AssemblyFile="$(RoslynTargetsPath)\Microsoft.Build.Tasks.CodeAnalysis.dll" />
-  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.Csc" AssemblyFile="$(RoslynTargetsPath)\Microsoft.Build.Tasks.CodeAnalysis.dll" />
-  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.Vbc" AssemblyFile="$(RoslynTargetsPath)\Microsoft.Build.Tasks.CodeAnalysis.dll" />
+  <!-- `Condition="Exists('$(RoslynTargetsPath)')` is needed because the package might not be yet downloaded during restore in VS
+        and we do not want to fail the restore phase because of that. -->
+  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.CopyRefAssembly" AssemblyFile="$(RoslynTargetsPath)\Microsoft.Build.Tasks.CodeAnalysis.dll" Condition="Exists('$(RoslynTargetsPath)')" />
+  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.Csc" AssemblyFile="$(RoslynTargetsPath)\Microsoft.Build.Tasks.CodeAnalysis.dll" Condition="Exists('$(RoslynTargetsPath)')" />
+  <UsingTask TaskName="Microsoft.CodeAnalysis.BuildTasks.Vbc" AssemblyFile="$(RoslynTargetsPath)\Microsoft.Build.Tasks.CodeAnalysis.dll" Condition="Exists('$(RoslynTargetsPath)')" />
 
   <ItemGroup Condition="'$(_NeedToDownloadMicrosoftNetSdkCompilersToolsetPackage)' == 'true'">
     <PackageDownload Include="Microsoft.Net.Sdk.Compilers.Toolset" Version="[$(NETCoreSdkVersion)]" />