From 6ad5f3625037b075961415f3cbabfaf7ee8f1417 Mon Sep 17 00:00:00 2001
From: Sarah Oslund <sfoslund@microsoft.com>
Date: Mon, 19 Jul 2021 14:32:14 -0700
Subject: [PATCH] Set pre-net5 win-arm64 to x64 by default

---
 .../targets/Microsoft.NET.RuntimeIdentifierInference.targets  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.RuntimeIdentifierInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.RuntimeIdentifierInference.targets
index 3bdab8eddd39..14a7a9066341 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.RuntimeIdentifierInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.RuntimeIdentifierInference.targets
@@ -137,6 +137,10 @@ Copyright (c) .NET Foundation. All rights reserved.
     <DefaultAppHostRuntimeIdentifier Condition="$(DefaultAppHostRuntimeIdentifier.EndsWith('arm64')) and
                                   $(DefaultAppHostRuntimeIdentifier.StartsWith('osx')) and
                                   $([MSBuild]::VersionLessThan('$(_TargetFrameworkVersionWithoutV)', '6.0'))">$(DefaultAppHostRuntimeIdentifier.Replace("arm64", "x64"))</DefaultAppHostRuntimeIdentifier>
+    <!-- If we are running on win-arm64 and the TFM is < 5.0, we have to use a x64 apphost since there are no win-arm64 apphosts previous to .NET 5.0. -->
+    <DefaultAppHostRuntimeIdentifier Condition="$(DefaultAppHostRuntimeIdentifier.EndsWith('arm64')) and
+                                  $(DefaultAppHostRuntimeIdentifier.StartsWith('win')) and
+                                  $([MSBuild]::VersionLessThan('$(_TargetFrameworkVersionWithoutV)', '5.0'))">$(DefaultAppHostRuntimeIdentifier.Replace("arm64", "x64"))</DefaultAppHostRuntimeIdentifier>
   </PropertyGroup>
 
   <Target Name="_CheckForUnsupportedAppHostUsage"