ci: run the Windows leg on the fleet's Windows VM

.github/workflows/main.yml

@@ -14,15 +14,19 @@ jobs:
   build:
     name: build-${{ matrix.platform }}
     # TRACE_CI_RUNNERS picks GitHub-hosted runners (unset) or the local fleet (`self-hosted`); see
-    # docs/self-hosted-runners.md in Trace Arena. Under the flag only the legs the local fleet can host exist:
-    # there is no Windows machine, and the arm64 Linux pool is a 1.5 GB container that cannot build the native
-    # runtime. Hosted CI keeps all four legs.
-    runs-on: ${{ vars.TRACE_CI_RUNNERS == 'self-hosted' && (matrix.platform == 'macos' && fromJSON('["self-hosted","macOS","ARM64"]') || fromJSON('["self-hosted","Linux","X64","yiazmat-linux-x64-native"]')) || (matrix.platform == 'windows' && 'windows-latest' || matrix.platform == 'macos' && 'macos-latest' || matrix.platform == 'linux-arm' && 'ubuntu-24.04-arm' || 'ubuntu-latest') }}
+    # docs/self-hosted-runners.md in Trace Arena. Under the flag the legs the local fleet can host exist: the Windows VM on the
+    # Linux server, the native x64 Linux server and the macOS machine. The arm64 Linux pool is a 1.5 GB container that cannot build
+    # the native runtime, so that leg stays hosted-only. Hosted CI keeps all four legs.
+    runs-on: ${{ vars.TRACE_CI_RUNNERS == 'self-hosted' && (matrix.platform == 'windows' && fromJSON('["self-hosted","Windows","X64"]') || matrix.platform == 'macos' && fromJSON('["self-hosted","macOS","ARM64"]') || fromJSON('["self-hosted","Linux","X64","yiazmat-linux-x64-native"]')) || (matrix.platform == 'windows' && 'windows-latest' || matrix.platform == 'macos' && 'macos-latest' || matrix.platform == 'linux-arm' && 'ubuntu-24.04-arm' || 'ubuntu-latest') }}
     env:
-      MONOGAME_WINDOWS_PLATFORM_TOOLSET: ${{ matrix.platform == 'windows' && 'v145' || '' }}
+      # The VSIX templates project needs the full Visual Studio IDE SDK, which the fleet's VM (Build Tools) does not have. The hosted
+      # legs keep building it.
+      MONOGAME_SKIP_VS_TEMPLATES: ${{ vars.TRACE_CI_RUNNERS == 'self-hosted' && matrix.platform == 'windows' && '1' || '' }}
+      # v145 ships with the newest Visual Studio; the fleet's Windows VM has VS 2022 Build Tools, whose toolset is v143.
+      MONOGAME_WINDOWS_PLATFORM_TOOLSET: ${{ matrix.platform == 'windows' && (vars.TRACE_CI_RUNNERS == 'self-hosted' && 'v143' || 'v145') || '' }}
     strategy:
       matrix:
-        platform: ${{ fromJSON(vars.TRACE_CI_RUNNERS == 'self-hosted' && '["macos","linux"]' || '["windows","macos","linux","linux-arm"]') }}
+        platform: ${{ fromJSON(vars.TRACE_CI_RUNNERS == 'self-hosted' && '["windows","macos","linux"]' || '["windows","macos","linux","linux-arm"]') }}
       fail-fast: false
     defaults:
       run:

MonoGame.Framework.Content.Pipeline/MonoGame.Framework.Content.Pipeline.csproj

@@ -141,7 +141,8 @@
     <PropertyGroup>
       <NativePlatformToolsetArgument Condition="'$(MONOGAME_WINDOWS_PLATFORM_TOOLSET)' != ''"> /p:PlatformToolset=$(MONOGAME_WINDOWS_PLATFORM_TOOLSET)</NativePlatformToolsetArgument>
     </PropertyGroup>
-    <Exec Command="&quot;$(MSBuildProgramFiles32)\Microsoft Visual Studio\Installer\vswhere.exe&quot; -latest -requires Microsoft.Component.MSBuild -find MSBuild\**\Bin\MSBuild.exe" ConsoleToMSBuild="true">
+    <!-- -products * so a Build Tools-only machine (the fleet's Windows VM) is found: vswhere's default product filter skips it. -->
+    <Exec Command="&quot;$(MSBuildProgramFiles32)\Microsoft Visual Studio\Installer\vswhere.exe&quot; -latest -products * -requires Microsoft.Component.MSBuild -find MSBuild\**\Bin\MSBuild.exe" ConsoleToMSBuild="true">
       <Output TaskParameter="ConsoleOutput" PropertyName="MGMSBuild" />
     </Exec>
     <!-- Generate Multi-Arch Solution -->

Tools/MonoGame.Tools.Tests/BuilderTests.cs

@@ -45,7 +45,10 @@ public void CommandLineParserTests()
             Assert.AreEqual(MakePath(Directory.GetCurrentDirectory(), "obj\\Content"), args.RootedIntermediateDirectory);
 
             args = ContentBuilderParams.Parse("build", "-s", "C:/This/Does/Not/Exist");
-            Assert.AreEqual(MakePath("C:/This/Does/Not/Exist"), args.SourceDirectory);
+            // The parser stores the directory relative to the working directory. On a different drive it cannot, and the path stays
+            // absolute (the hosted runners work on D:); on the same drive it relativizes (the fleet's VM works on C:). Assert the
+            // round trip, not the hosted image's drive layout.
+            Assert.AreEqual(MakePath(Path.GetRelativePath(Directory.GetCurrentDirectory(), "C:/This/Does/Not/Exist")), args.SourceDirectory);
 
             args = ContentBuilderParams.Parse(
                 "build",

build/BuildTemplatesTasks/BuildVSTemplatesTask.cs

@@ -6,7 +6,10 @@ namespace BuildScripts;
 [IsDependentOn(typeof(BuildDotNetTemplatesTask))]
 public sealed class BuildVSTemplatesTask : FrostingTask<BuildContext>
 {
-    public override bool ShouldRun(BuildContext context) => context.IsRunningOnWindows();
+    // The VSIX project needs the full Visual Studio IDE SDK (VSSDK1077: no extensions directory on a Build Tools-only machine).
+    // The workflow sets the variable for the self-hosted Windows VM, which has the Build Tools; the hosted legs keep building it.
+    public override bool ShouldRun(BuildContext context) =>
+        context.IsRunningOnWindows() && Environment.GetEnvironmentVariable("MONOGAME_SKIP_VS_TEMPLATES") != "1";
 
     public override void Run(BuildContext context)
     {

build/TestNuGetsTasks/TestMonoGameTemplateTaskBase.cs

@@ -190,6 +190,25 @@ private void UninstallExistingTemplates(BuildContext context)
 
     private void InstallTemplates(BuildContext context, string templateVersion, string nugetSourcePath)
     {
+        // `dotnet new uninstall` removes the template but leaves its package in ~/.templateengine/packages, and the next
+        // `dotnet new install` of the same version fails with "File ... already exists" (templating exit code 106) instead of
+        // reinstalling. Clear the cached package so a rerun on the same machine starts from a clean template store.
+        var templateCache = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".templateengine", "packages");
+        if (Directory.Exists(templateCache))
+        {
+            foreach (var cached in Directory.GetFiles(templateCache, "MonoGame.Templates.CSharp.*.nupkg"))
+            {
+                try
+                {
+                    File.Delete(cached);
+                }
+                catch (IOException)
+                {
+                    // A package held open by another dotnet process: the install below will report it if it matters.
+                }
+            }
+        }
+
         context.Information($"Installing MonoGame templates version {templateVersion}...");
         context.StartProcess("dotnet", new ProcessSettings
         {

build/Utils/StaticLibCheck.cs

@@ -48,7 +48,8 @@ public static class StaticLibCheck
     public static void CheckWindows(BuildContext context, string filePath)
     {
         var vswhere = new VSWhereLatest(context.FileSystem, context.Environment, context.ProcessRunner, context.Tools);
-        var devcmdPath = vswhere.Latest(new VSWhereLatestSettings()).FullPath + @"\Common7\Tools\vsdevcmd.bat";
+        // Products = "*" so a Build Tools-only machine (the fleet's Windows VM) is found: the default product filter skips it.
+        var devcmdPath = vswhere.Latest(new VSWhereLatestSettings { Products = "*" }).FullPath + @"\Common7\Tools\vsdevcmd.bat";
 
         context.StartProcess(
             devcmdPath,