Use real SdkResolver APIs to set .NET environment variables for .NET TaskHost purposes by baronfel · Pull Request #50091 · dotnet/sdk

baronfel · 2025-08-06T17:32:17Z

This uses the proper APIs for reporting Environment Variables to be set by the SdkResolvers, but because it requires a newer version of the MSBuild APIs and those APIs have brought increased dependency bumps we probably need to take a deeper look at the coordination involved here.

…ations, report all VS-env validation errors in one batch

Copilot

Pull Request Overview

This PR updates the MSBuild SDK resolver to use proper SDK resolver APIs for setting .NET environment variables, specifically moving from using the deprecated DOTNET_EXPERIMENTAL_HOST_PATH property to the newer DOTNET_HOST environment variable through the SDK resolver's EnvironmentVariablesToAdd property.

Key changes:

Migrates from properties-based to environment variables-based approach for passing .NET host information
Updates MSBuild dependencies to newer versions to support the enhanced SDK resolver APIs
Updates tests to verify the new environment variable approach instead of the old property-based approach

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
MSBuildSdkResolver.cs	Core implementation change from properties to environment variables for DOTNET_HOST
GivenAnMSBuildSdkResolver.cs	Test updates to verify environment variables instead of properties
Microsoft.DotNet.MSBuildSdkResolver.csproj	Updated dependency versions and error handling for dependency validation
Versions.props	Updated MSBuild and related package versions to support new APIs
build.sh/build.cmd	Added build summary logging flags

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

Copilot · 2025-08-06T17:32:55Z

eng/Versions.props

    <MicrosoftBuildVersion>17.15.0-preview-25377-103</MicrosoftBuildVersion>
    <MicrosoftBuildLocalizationVersion>17.15.0-preview-25377-103</MicrosoftBuildLocalizationVersion>
-    <MicrosoftBuildMinimumVersion Condition="'$(DotNetBuildSourceOnly)' != 'true'">17.11.4</MicrosoftBuildMinimumVersion>
+    <!-- TODO: ensure the right version actually gets inserted -->


The TODO comment indicates uncertainty about version handling. This should be resolved before merging to ensure the correct MSBuild version is being used.

Suggested change

baronfel · 2025-08-06T18:09:03Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

+      <ExpectedDependencies Include="Microsoft.Bcl.AsyncInterfaces, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
      <ExpectedDependencies Include="Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
-      <ExpectedDependencies Include="System.Collections.Immutable, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
-      <ExpectedDependencies Include="System.Memory, Version=4.0.1.2, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
-      <ExpectedDependencies Include="Microsoft.Bcl.AsyncInterfaces, Version=8.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
-      <ExpectedDependencies Include="System.Runtime.CompilerServices.Unsafe, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
-      <ExpectedDependencies Include="System.Numerics.Vectors, Version=4.1.4.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
-      <ExpectedDependencies Include="System.Buffers, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="Microsoft.Deployment.DotNet.Releases, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
+      <ExpectedDependencies Include="System.Buffers, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Collections.Immutable, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+      <!-- <ExpectedDependencies Include="System.Diagnostics.DiagnosticSource, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" /> -->
+      <ExpectedDependencies Include="System.IO.Pipelines, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Memory, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Numerics.Vectors, Version=4.1.6.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+      <ExpectedDependencies Include="System.Runtime.CompilerServices.Unsafe, Version=6.0.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+      <ExpectedDependencies Include="System.Text.Encodings.Web, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Text.Json, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />


These expected versions need checking

per @marcpopMSFT's comment here, use the versions from https://github.com/dotnet/msbuild/blob/vs17.15/src/MSBuild/app.amd64.config for checking these.

baronfel · 2025-08-06T18:09:31Z

eng/Versions.props

+    <MicrosoftBclAsyncInterfacesToolsetPackageVersion>9.0.0</MicrosoftBclAsyncInterfacesToolsetPackageVersion>
    <MicrosoftDeploymentDotNetReleasesToolsetPackageVersion>2.0.0-preview.1.24427.4</MicrosoftDeploymentDotNetReleasesToolsetPackageVersion>
    <SystemBuffersToolsetPackageVersion>4.5.1</SystemBuffersToolsetPackageVersion>
-    <SystemCollectionsImmutableToolsetPackageVersion>8.0.0</SystemCollectionsImmutableToolsetPackageVersion>
+    <SystemCollectionsImmutableToolsetPackageVersion>9.0.0</SystemCollectionsImmutableToolsetPackageVersion>
    <SystemMemoryToolsetPackageVersion>4.5.5</SystemMemoryToolsetPackageVersion>
-    <SystemReflectionMetadataLoadContextToolsetPackageVersion>8.0.0</SystemReflectionMetadataLoadContextToolsetPackageVersion>
-    <SystemReflectionMetadataToolsetPackageVersion>8.0.0</SystemReflectionMetadataToolsetPackageVersion>
-    <SystemTextJsonToolsetPackageVersion>8.0.5</SystemTextJsonToolsetPackageVersion>
+    <SystemReflectionMetadataLoadContextToolsetPackageVersion>9.0.0</SystemReflectionMetadataLoadContextToolsetPackageVersion>
+    <SystemReflectionMetadataToolsetPackageVersion>9.0.0</SystemReflectionMetadataToolsetPackageVersion>
+    <SystemTextJsonToolsetPackageVersion>9.0.0</SystemTextJsonToolsetPackageVersion>
    <SystemThreadingTasksExtensionsToolsetPackageVersion>4.5.4</SystemThreadingTasksExtensionsToolsetPackageVersion>
-    <SystemResourcesExtensionsToolsetPackageVersion>8.0.0</SystemResourcesExtensionsToolsetPackageVersion>
+    <SystemResourcesExtensionsToolsetPackageVersion>9.0.0</SystemResourcesExtensionsToolsetPackageVersion>


These bumps were necessary IIRC because the higher MSBuild version below dragged them upwards.

baronfel

Quick pass through the versions in the vs17.15 branch of msbuild and noting what's out of sync

baronfel · 2025-08-08T19:48:13Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

-      <ExpectedDependencies Include="System.Numerics.Vectors, Version=4.1.4.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
-      <ExpectedDependencies Include="System.Buffers, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="Microsoft.Deployment.DotNet.Releases, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
+      <ExpectedDependencies Include="System.Buffers, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />


out of sync with msbuild: 4.0.4.0

baronfel · 2025-08-08T19:49:04Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

+      <ExpectedDependencies Include="System.Collections.Immutable, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+      <!-- <ExpectedDependencies Include="System.Diagnostics.DiagnosticSource, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" /> -->
+      <ExpectedDependencies Include="System.IO.Pipelines, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Memory, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />


out of sync with msbuild: 4.0.2.0

baronfel · 2025-08-08T19:49:42Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

+      <!-- <ExpectedDependencies Include="System.Diagnostics.DiagnosticSource, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" /> -->
+      <ExpectedDependencies Include="System.IO.Pipelines, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Memory, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Numerics.Vectors, Version=4.1.6.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />


out of sync with msbuild: 4.1.5.0

baronfel · 2025-08-08T19:50:13Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

+      <ExpectedDependencies Include="System.IO.Pipelines, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Memory, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Numerics.Vectors, Version=4.1.6.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+      <ExpectedDependencies Include="System.Runtime.CompilerServices.Unsafe, Version=6.0.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />


out of sync with msbuild: 6.0.1.0

baronfel · 2025-08-08T19:50:56Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/Microsoft.DotNet.MSBuildSdkResolver.csproj

+      <ExpectedDependencies Include="Microsoft.Deployment.DotNet.Releases, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
+      <ExpectedDependencies Include="System.Buffers, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
+      <ExpectedDependencies Include="System.Collections.Immutable, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+      <!-- <ExpectedDependencies Include="System.Diagnostics.DiagnosticSource, Version=9.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" /> -->


This one is present, can uncomment it

baronfel · 2025-08-08T22:04:24Z

for now we are going to roll back most of the actual version updates and direct usage of the MSBuild API in this PR, because bumping the MSBuild version here to 17.15 will make all of the SdkResolver tests in the Full-Framework CI leg fail. This is because those legs test the SdkResolver in situ - using msbuild.exe from the curently-released version of VS. In this case that's 17.14, and the 17.15 MSBuild DLLs will not load in this environment at all.

To get the functionality in while not blocking the entire Full-Framework CI leg, we're instead going to use a cached reflection lookup to see if we can find the new factory function overload with the environment variable parameter. If we can, we will call that. If we cannot, we will call use the previous logic. We will also skip the tests that I added for this functionality.

When there is an updated VS version available in the Full-Framework leg we will

remove the reflection usage,
bump versions,
reenable the tests

In the meantime, the MSBuild team dogfooding this via the SDK will let us know if there are any regressions in this area.

baronfel · 2025-08-09T19:01:59Z

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/MSBuildSdkResolver.cs

+        private const string SdkResolverGlobalJsonPath = "SdkResolverGlobalJsonPath";
        private static CachingWorkloadResolver _staticWorkloadResolver = new();

+        /// <summary>


@dsplaisted I've made that change we talked about now - want to check me? I did load the updated MSBuild dll in an FSI session and made sure that the reflection-based lookup below does in fact resolve.

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/MSBuildSdkResolver.cs

baronfel added 3 commits August 6, 2025 12:29

use TL summary all the time beacuse we have a big build

47acf59

bump MSBuild API versions and dependencies, hack through VS-env valid…

61825e3

…ations, report all VS-env validation errors in one batch

set env vars from resolver APIs

ea55de9

baronfel requested review from a team, Copilot and rainersigwald August 6, 2025 17:32

Copilot AI reviewed Aug 6, 2025

View reviewed changes

baronfel assigned dsplaisted Aug 6, 2025

align versions - this needs review

52f3db2

baronfel commented Aug 6, 2025

View reviewed changes

This was referenced Aug 6, 2025

The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008

Open

[dotnet watch] Cannot open project Lib.fsproj because extension fsproj is not associated with a language #46378

Closed

baronfel commented Aug 8, 2025

View reviewed changes

use reflection to find capable API if present

ea7eee9

baronfel commented Aug 9, 2025

View reviewed changes

keep older fallback for VS backcompat

9e64a2c

dsplaisted reviewed Aug 10, 2025

View reviewed changes

src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/MSBuildSdkResolver.cs Outdated Show resolved Hide resolved

use a delegate and doc it!

cb45b92

YuliiaKovalova approved these changes Aug 11, 2025

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dsplaisted approved these changes Aug 11, 2025

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dsplaisted merged commit 0062d0a into dotnet:main Aug 11, 2025
27 checks passed

YuliiaKovalova mentioned this pull request Aug 22, 2025

Set DOTNET_HOST_PATH from property after MSBuildSdkResolver resolution dotnet/msbuild#12017

Closed

baronfel mentioned this pull request Sep 24, 2025

Make the new SdkResolver set the proper DOTNET_HOST_PATH env var instead of the non-functional DOTNET_HOST env var dotnet/dotnet#2592

Merged

	<!-- TODO: ensure the right version actually gets inserted -->
	<!-- The correct MSBuild version is set via MicrosoftBuildVersion; ensure this matches the intended minimum version for non-source-only builds. -->

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