Make private runtime-only dependencies on .NET Standard 2.0. by teo-tsirpanis · Pull Request #11109 · dotnet/msbuild

teo-tsirpanis · 2024-12-07T22:48:54Z

Context

Since #6148 we produce only reference assemblies for .NET Standard 2.0, which means that several of the our NuGet packages' dependencies when targeting .NET Standard 2.0 are unused.

Changes Made

The project files for Microsoft.Build.Framework, Utilities.Core and Tasks were updated to apply PrivateAssets="all" to all package references that are not exposed in the package's public API, when targeting .NET Standard 2.0.

Testing

I ran dotnet pack on these projects and validated manually that on .NET Standard 2.0, Microsoft.Build.Framework has zero dependencies, Utilities.Core depends only on Framework, and Tasks depends only on the previous two.

Because Roslyn keeps some internal APIs in reference assemblies, these reference assemblies still reference some assemblies whose respective package is not depended upon. I manually validated with ILSpy that the types in these assemblies are used only by internal APIs.

Notes

This is going to be a (minor) source-breaking change if a .NET Standard 2.0 project uses APIs from on one of the removed packages and transitively depended on it. They will have to directly depend on them, and it's not the first time we do a change like this (#9055).

I don't think that this is a binary-breaking change because the .NET Standard 2.0 binaries are not being used at runtime.

The reference to immutable collections is surfaced to `Framework`. This lightens the NS2.0 reference assembly.

rainersigwald · 2024-12-10T16:54:35Z

Nice, I've been planning to do something like this (and likely even going further). Will look shortly.

teo-tsirpanis · 2024-12-10T18:37:54Z

and likely even going further

Let me know how further this can go, happy to do it now or in a subsequent PR.

JanProvaznik · 2025-07-08T09:17:06Z

sorry for letting this be stale for such a long time. The spirit of the change is good, though it breaks CI now (not sure if it ever passed or just accumulated divergence from December). @teo-tsirpanis are you interested in finishing it?

teo-tsirpanis · 2025-07-10T19:56:29Z

This failure is interesting:

There was a conflict between "System.Memory, Version=4.0.1.2, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" and "System.Memory, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51".
    "System.Memory, Version=4.0.1.2, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" was chosen because it was primary and "System.Memory, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" was not.
    References which depend on "System.Memory, Version=4.0.1.2, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" [D:\a\1\s\.packages\system.memory\4.5.5\lib\netstandard2.0\System.Memory.dll].
        D:\a\1\s\.packages\system.memory\4.5.5\lib\netstandard2.0\System.Memory.dll
          Project file item includes which caused reference "D:\a\1\s\.packages\system.memory\4.5.5\lib\netstandard2.0\System.Memory.dll".
            D:\a\1\s\.packages\system.memory\4.5.5\lib\netstandard2.0\System.Memory.dll
    References which depend on or have been unified to "System.Memory, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" [].
        D:\a\1\s\artifacts\bin\Microsoft.Build.Framework\Debug\netstandard2.0\Microsoft.Build.Framework.dll
          Project file item includes which caused reference "D:\a\1\s\artifacts\bin\Microsoft.Build.Framework\Debug\netstandard2.0\Microsoft.Build.Framework.dll".
            D:\a\1\s\artifacts\bin\Microsoft.Build.Framework\Debug\netstandard2.0\Microsoft.Build.Framework.dll
            D:\a\1\s\artifacts\bin\Microsoft.Build.Utilities\Debug\netstandard2.0\Microsoft.Build.Utilities.Core.dll
        D:\a\1\s\artifacts\bin\Microsoft.Build.Utilities\Debug\netstandard2.0\Microsoft.Build.Utilities.Core.dll
          Project file item includes which caused reference "D:\a\1\s\artifacts\bin\Microsoft.Build.Utilities\Debug\netstandard2.0\Microsoft.Build.Utilities.Core.dll".
            D:\a\1\s\artifacts\bin\Microsoft.Build.Utilities\Debug\netstandard2.0\Microsoft.Build.Utilities.Core.dll

Could it be because we inject references to specific versions of maintainenance packages in test projects?

….NET Standard 2.0.

teo-tsirpanis · 2025-07-12T17:43:56Z

@JanProvaznik CI is now green.

Most failures were due to my moving of the Microsoft.CodeAnalysis.Collections dependency to Build; that package had its own Strings.resx file, which caused name clashes with Build's own Strings.resx (Framework didn't have a Strings.resx, hence no clashes).

The solution is to update MS.CA.C to a version with dotnet/roslyn#78576, but because it is a more involved change, I rolled back that commit for now, and opened #12161.

This reverts commit 60122d6.

src/Build/Microsoft.Build.csproj

src/Framework/Microsoft.Build.Framework.csproj

Copilot

Pull Request Overview

This PR modifies three MSBuild project files to mark runtime-only dependencies as private when targeting .NET Standard 2.0, reducing transitive dependencies in reference assemblies. Since #6148 introduced reference-only assemblies for .NET Standard 2.0, many package dependencies are no longer needed at runtime.

Applied PrivateAssets="all" to packages not exposed in public APIs for .NET Standard 2.0 targets
Removed explicit package references that are now handled by the private assets pattern
Validated that dependency chains are simplified (Framework has zero dependencies, Utilities.Core depends only on Framework, Tasks depends only on the previous two)

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/Framework/Microsoft.Build.Framework.csproj	Marks System.Collections.Immutable and System.Diagnostics.DiagnosticSource as private assets, removes Microsoft.Win32.Registry reference
src/Utilities/Microsoft.Build.Utilities.csproj	Marks multiple dependencies as private assets including StringTools project reference and several System packages, removes System.Text.Encoding.CodePages reference
src/Tasks/Microsoft.Build.Tasks.csproj	Consolidates and marks multiple dependencies as private assets, moves some package references from conditional to private assets pattern

Comments suppressed due to low confidence (1)

src/Utilities/Microsoft.Build.Utilities.csproj:35

The removal of System.Text.Encoding.CodePages package reference is not replaced with a private assets equivalent in the new ItemGroup below. If this package is still needed for .NET Standard 2.0, it should be included with PrivateAssets="all" in the conditional ItemGroup.

  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETStandard'">

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rainersigwald

This is fantastic, thank you! Sorry for the delayed merge.

Make private runtime-only dependencies on .NET Standard 2.0.

75356a3

teo-tsirpanis force-pushed the ns2.0-refs branch from f220ecc to 16f3b06 Compare December 8, 2024 01:33

Move MS.CA.Collections dependency to Build.

60122d6

The reference to immutable collections is surfaced to `Framework`. This lightens the NS2.0 reference assembly.

teo-tsirpanis force-pushed the ns2.0-refs branch from 16f3b06 to 60122d6 Compare December 8, 2024 09:30

YuliiaKovalova requested a review from rainersigwald December 10, 2024 10:54

ghost assigned JanProvaznik Jul 7, 2025

Merge branch 'main' into ns2.0-refs

5bf12bb

JanProvaznik added the needs-more-info Issues that need more info to continue investigation. label Jul 10, 2025

teo-tsirpanis added 2 commits July 12, 2025 17:20

Merge branch 'main' into ns2.0-refs

142f76d

Make private the System.Diagnostics.DiagnosticSource dependency on …

ae35bb6

….NET Standard 2.0.

teo-tsirpanis mentioned this pull request Jul 12, 2025

Update Microsoft.CodeAnalysis.Collections et al. #12161

Merged

Revert "Move MS.CA.Collections dependency to Build."

0170975

This reverts commit 60122d6.

teo-tsirpanis force-pushed the ns2.0-refs branch from 434f802 to 0170975 Compare July 13, 2025 15:40

Merge branch 'main' into ns2.0-refs

f39701f

JanProvaznik approved these changes Jul 14, 2025

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JanProvaznik added the backlog label Jul 17, 2025

teo-tsirpanis added 2 commits July 17, 2025 15:08

Address PR feedback.

d4f875a

Fix typo.

cfe02d2

JanProvaznik removed the needs-more-info Issues that need more info to continue investigation. label Jul 17, 2025

JanProvaznik added 2 commits July 17, 2025 14:28

Merge branch 'main' into ns2.0-refs

d57367b

Merge branch 'main' into ns2.0-refs

9768c04

Copilot AI review requested due to automatic review settings August 18, 2025 08:38

Copilot AI reviewed Aug 18, 2025

View reviewed changes

Merge branch 'main' into ns2.0-refs

4e69da5

rainersigwald approved these changes Sep 5, 2025

View reviewed changes

JanProvaznik merged commit 0bc107d into dotnet:main Sep 5, 2025
9 checks passed

teo-tsirpanis deleted the ns2.0-refs branch September 5, 2025 14:42

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Make private runtime-only dependencies on .NET Standard 2.0.#11109

Make private runtime-only dependencies on .NET Standard 2.0.#11109
JanProvaznik merged 12 commits intodotnet:mainfrom
teo-tsirpanis:ns2.0-refs

teo-tsirpanis commented Dec 7, 2024

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rainersigwald commented Dec 10, 2024

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teo-tsirpanis commented Dec 10, 2024

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teo-tsirpanis commented Dec 7, 2024

Context

Changes Made

Testing

Notes

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rainersigwald commented Dec 10, 2024

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teo-tsirpanis commented Dec 10, 2024

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JanProvaznik commented Jul 8, 2025

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teo-tsirpanis commented Jul 10, 2025

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teo-tsirpanis commented Jul 12, 2025

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