Port infra from release/3.1 to setup internal feeds correctly

Author: dseefeld

repos/Directory.Build.targets

@@ -113,8 +113,10 @@
       <NuGetConfigFiles Include="$(NuGetConfigFile)" />
     </ItemGroup>
 
-    <RemoveInternetSourcesFromNuGetConfig NuGetConfigFile="%(NuGetConfigFiles.Identity)"
-                                          OfflineBuild="$(OfflineBuild)" />
+    <RemoveInternetSourcesFromNuGetConfig
+      NuGetConfigFile="%(NuGetConfigFiles.Identity)"
+      OfflineBuild="$(OfflineBuild)"
+      KeepFeedPrefixes="@(KeepFeedPrefixes)" />
 
     <AddSourceToNuGetConfig NuGetConfigFile="%(NuGetConfigFiles.Identity)"
                             SourceName="prebuilt"
@@ -140,6 +142,18 @@
                             SourcePath="$(ExtraRestoreSourcePath)"
                             Condition="'$(ExtraRestoreSourcePath)' != ''" />
 
+    <!--
+      The internal transport feed is dynamically added by Arcade by a script called directly in the
+      official pipeline, so in some cases we need to do the same here.
+    -->
+    <AddSourceToNuGetConfig
+      Condition="
+        '$(VSS_NUGET_EXTERNAL_FEED_ENDPOINTS)' != '' and
+        '$(SetUpInternalTransportFeed)' == 'true'"
+      NuGetConfigFile="%(NuGetConfigFiles.Identity)"
+      SourceName="dotnet5-internal-transport"
+      SourcePath="https://pkgs.dev.azure.com/dnceng/internal/_packaging/dotnet5-internal-transport/nuget/v3/index.json" />
+
     <!-- Update NuGet.Config files that have deprecated myget feeds -->
     <ItemGroup>
       <LegacyFeedMapping

repos/installer.proj

@@ -63,6 +63,9 @@
     <!-- This project builds zips, not NuGet packages. -->
     <SkipEnsurePackagesCreated>true</SkipEnsurePackagesCreated>
     <NuGetConfigFile>$(ProjectDirectory)/NuGet.config</NuGetConfigFile>
+
+    <!-- This repo uses text-only template packages from the internal transport feed. -->
+    <SetUpInternalTransportFeed>true</SetUpInternalTransportFeed>
   </PropertyGroup>
 
   <ItemGroup>
@@ -89,6 +92,15 @@
     <RepositoryReference Include="xliff-tasks" />
   </ItemGroup>
 
+  <!--
+    If we have authentication, keep the templating internal feed (if one exists) to acquire the
+    text-only prebuilt. The source-build repo as a whole should depend on the same internal feed as
+    this repo does, so authentication should already be set up in the global endpoints json.
+  -->
+  <ItemGroup Condition="'$(VSS_NUGET_EXTERNAL_FEED_ENDPOINTS)' != ''">
+    <KeepFeedPrefixes Include="darc-int-dotnet-aspnetcore-" />
+  </ItemGroup>
+
   <ItemGroup>
     <EnvironmentVariables Include="CLIBUILD_SKIP_TESTS=true" />
 

tools-local/tasks/Microsoft.DotNet.SourceBuild.Tasks.XPlat/RemoveInternetSourcesFromNuGetConfig.cs

@@ -27,6 +27,13 @@ public class RemoveInternetSourcesFromNuGetConfig : Task
         /// </summary>
         public bool OfflineBuild { get; set; }
 
+        /// <summary>
+        /// A list of prefix strings that make the task keep a package source unconditionally. For
+        /// example, a source named 'darc-pub-dotnet-aspnetcore-e81033e' will be kept if the prefix
+        /// 'darc-pub-dotnet-aspnetcore-' is in this list.
+        /// </summary>
+        public string[] KeepFeedPrefixes { get; set; }
+
         public override bool Execute()
         {
             XDocument d = XDocument.Load(NuGetConfigFile);
@@ -36,6 +43,14 @@ public override bool Execute()
             {
                 if (e.Name == "add")
                 {
+                    string feedName = e.Attribute("key").Value;
+                    if (KeepFeedPrefixes
+                        ?.Any(prefix => feedName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+                        == true)
+                    {
+                        return true;
+                    }
+
                     string feedUrl = e.Attribute("value").Value;
                     if (OfflineBuild)
                     {