Remove Polyfill NuGet package dependency by Evangelink · Pull Request #7597 · microsoft/testfx

Evangelink · 2026-03-24T10:32:34Z

Replace the Polyfill NuGet package with a self-contained eng/Polyfills.cs file and project-specific polyfill extension methods.

Changes

Remove Polyfill PackageReference from all 35 csproj files
Remove Polyfill configuration (PolyEnsure, PolyGuard, PolyStringInterpolation, PolyUseEmbeddedAttribute) from Directory.Build.props
Remove PackageVersion entry from Directory.Packages.props
Remove global <Using Include="Polyfills" /> directives from 12 csproj files
Remove explicit using Polyfills; from source files
Remove Polyfill-specific GlobalSuppressions entry

Replacements

eng/Polyfills.cs — Shared polyfill types and attributes for older TFMs (netstandard2.0, net462): nullable attributes, compiler attributes, ExperimentalAttribute, Index/Range, Lock, OperatingSystem, UnreachableException, Ensure helper, etc.
Project-specific polyfill extensions — Extension methods scoped to projects that need them to avoid IVT ambiguity:
- src/Platform/Microsoft.Testing.Platform/Helpers/KeyValuePairDeconstruct.cs
- src/Platform/Microsoft.Testing.Extensions.TrxReport.Abstractions/PolyfillExtensions.cs
- src/TestFramework/TestFramework/Internal/PolyfillExtensions.cs
- src/Adapter/MSTestAdapter.PlatformServices/PolyfillExtensions.cs
- src/Analyzers/MSTest.Analyzers/RoslynAnalyzerHelpers/AnalyzerPolyfillExtensions.cs

Call-site fixes

Fixed code that relied on Polyfill-provided APIs not available on older TFMs: SHA256.HashData, Convert.ToHexStringLower, Environment.ProcessId, File.Move (3-arg), File.ReadAllTextAsync, Enum.Parse<T>, Enum.GetNames<T>, Enum.IsDefined<T>, Enum.GetValues<T>, XElement.LoadAsync, XDocument.SaveAsync, Type.IsGenericMethodParameter, string.Join(char, ...), ConcurrentBag.Clear, ConcurrentDictionary.GetOrAdd (3-arg), and TextWriter.FlushAsync(CancellationToken).

Fixes #7596

Replace the Polyfill NuGet package with a self-contained eng/Polyfills.cs file and project-specific polyfill extensions. - Remove Polyfill PackageReference from all 35 csproj files - Remove Polyfill configuration (PolyEnsure, PolyGuard, etc.) from Directory.Build.props - Remove PackageVersion from Directory.Packages.props - Remove global using Polyfills directives from csproj files - Add eng/Polyfills.cs with type stubs and attributes for older TFMs - Add project-specific polyfill extension methods where needed - Fix call sites for APIs not available on netstandard2.0/net462 Fixes #7596

Copilot

Pull request overview

This PR removes the third-party Polyfill NuGet dependency across the repo and replaces it with a shared, source-included polyfill implementation (eng/Polyfills.cs) plus a few project-scoped polyfill extension files to keep older TFMs building cleanly.

Changes:

Removed Polyfill PackageReference entries (and related MSBuild config/global usings) across projects.
Added eng/Polyfills.cs and wired it into builds via Directory.Build.props.
Updated call sites to avoid APIs/overloads not available on older TFMs (e.g., Enum.Parse<T>, Environment.ProcessId, async XML load/save, etc.).

Reviewed changes

Copilot reviewed 67 out of 67 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
test/Utilities/TestFramework.ForTestingMSTest/TestFramework.ForTestingMSTest.csproj	Removes Polyfill package reference.
test/Utilities/Microsoft.Testing.TestInfrastructure/Microsoft.Testing.TestInfrastructure.csproj	Removes Polyfill package reference and Polyfills using.
test/Utilities/Automation.CLI/Automation.CLI.csproj	Removes Polyfill package reference.
test/UnitTests/TestFramework.UnitTests/TestFramework.UnitTests.csproj	Removes Polyfill package reference.
test/UnitTests/TestFramework.UnitTests/Assertions/AssertTests.AreEqualTests.cs	Switches to `Split(char)` overload for compatibility.
test/UnitTests/Microsoft.Testing.Platform.UnitTests/Microsoft.Testing.Platform.UnitTests.csproj	Removes Polyfill package reference and Polyfills using.
test/UnitTests/Microsoft.Testing.Extensions.VSTestBridge.UnitTests/Microsoft.Testing.Extensions.VSTestBridge.UnitTests.csproj	Removes Polyfill package reference.
test/UnitTests/Microsoft.Testing.Extensions.UnitTests/Microsoft.Testing.Extensions.UnitTests.csproj	Removes Polyfill package reference.
test/UnitTests/MSTestAdapter.UnitTests/MSTestAdapter.UnitTests.csproj	Removes Polyfill package reference.
test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/ObjectModel/UnitTestElementTests.cs	Replaces `Enum.GetValues<T>()` with non-generic overload for older TFMs.
test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/MSTestAdapter.PlatformServices.UnitTests.csproj	Removes Polyfill package reference.
test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/Discovery/TypeEnumeratorTests.MockedMethodInfoWithExtraAttributes.cs	Removes conditional `using Polyfills;`.
test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj	Removes Polyfill package reference.
test/IntegrationTests/Microsoft.Testing.Platform.Acceptance.IntegrationTests/Microsoft.Testing.Platform.Acceptance.IntegrationTests.csproj	Removes Polyfill package reference.
test/IntegrationTests/MSTest.IntegrationTests/Utilities/TestCaseFilterFactory.cs	Removes `using Polyfills;`.
test/IntegrationTests/MSTest.IntegrationTests/MSTest.IntegrationTests.csproj	Removes Polyfill package reference.
test/IntegrationTests/MSTest.Acceptance.IntegrationTests/MSTest.Acceptance.IntegrationTests.csproj	Removes Polyfill package reference.
src/TestFramework/TestFramework/TestFramework.csproj	Removes Polyfill package reference and Polyfills using.
src/TestFramework/TestFramework/Internal/TestDataSourceUtilities.cs	Replaces `string.Join(char, …)` with string separator overload for older TFMs.
src/TestFramework/TestFramework/Internal/PolyfillExtensions.cs	Adds TestFramework-scoped polyfill extensions.
src/TestFramework/TestFramework.Extensions/TestFramework.Extensions.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Platform/Services/ExecutableInfo.cs	Replaces `string.Join(char, …)` usage with string separator overload.
src/Platform/Microsoft.Testing.Platform/ServerMode/JsonRpc/TcpMessageHandler.cs	Adjusts flush logic to avoid `FlushAsync(CancellationToken)` dependency.
src/Platform/Microsoft.Testing.Platform/ServerMode/JsonRpc/ServerModePerCallOutputDevice.cs	Replaces `ConcurrentBag.Clear()` with fallback loop for non-NETCOREAPP.
src/Platform/Microsoft.Testing.Platform/ServerMode/JsonRpc/SerializerUtilities.cs	Replaces `string.Join(char, …)` usage with string separator overload.
src/Platform/Microsoft.Testing.Platform/Microsoft.Testing.Platform.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Platform/Helpers/System/SystemFileSystem.cs	Adds polyfilled `File.Move(overwrite)` and async file-read fallback.
src/Platform/Microsoft.Testing.Platform/Helpers/System/SystemEnvironment.cs	Adds `Environment.ProcessId` fallback for older TFMs.
src/Platform/Microsoft.Testing.Platform/Helpers/Sha256Hasher.cs	Adds hashing/hex formatting fallbacks for older TFMs.
src/Platform/Microsoft.Testing.Platform/Helpers/KeyValuePairDeconstruct.cs	Adds Platform-scoped `KeyValuePair` `Deconstruct` polyfill.
src/Platform/Microsoft.Testing.Platform/Builder/TestApplication.cs	Replaces `Enum.Parse<T>` with non-generic overload for older TFMs.
src/Platform/Microsoft.Testing.Platform.MSBuild/Tasks/InvokeTestingPlatformTask.cs	Replaces `Enum.Parse<T>` with non-generic overloads for older TFMs.
src/Platform/Microsoft.Testing.Platform.MSBuild/Microsoft.Testing.Platform.MSBuild.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Platform.AI/Microsoft.Testing.Platform.AI.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.VSTestBridge/Microsoft.Testing.Extensions.VSTestBridge.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Extensions.TrxReport/TrxReportEngine.cs	Adds async XML save fallback for non-NETCOREAPP.
src/Platform/Microsoft.Testing.Extensions.TrxReport/TrxCompareTool.cs	Adds async XML load fallback for non-NETCOREAPP.
src/Platform/Microsoft.Testing.Extensions.TrxReport/Microsoft.Testing.Extensions.TrxReport.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Extensions.TrxReport/Hashing/EmbeddedAttribute.cs	Removes local EmbeddedAttribute in favor of shared polyfills file.
src/Platform/Microsoft.Testing.Extensions.TrxReport.Abstractions/PolyfillExtensions.cs	Adds Abstractions-scoped polyfill extensions (`StringBuilder.AppendJoin`).
src/Platform/Microsoft.Testing.Extensions.TrxReport.Abstractions/Microsoft.Testing.Extensions.TrxReport.Abstractions.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Extensions.TrxReport.Abstractions/GlobalSuppressions.cs	Removes Polyfill-specific suppression entry.
src/Platform/Microsoft.Testing.Extensions.Telemetry/Microsoft.Testing.Extensions.Telemetry.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Extensions.Retry/Microsoft.Testing.Extensions.Retry.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.OpenTelemetry/Microsoft.Testing.Extensions.OpenTelemetry.csproj	Removes Polyfill package reference and Polyfills using.
src/Platform/Microsoft.Testing.Extensions.MSBuild/Microsoft.Testing.Extensions.MSBuild.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.HotReload/Microsoft.Testing.Extensions.HotReload.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.HangDump/Microsoft.Testing.Extensions.HangDump.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.CrashDump/Microsoft.Testing.Extensions.CrashDump.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.AzureFoundry/Microsoft.Testing.Extensions.AzureFoundry.csproj	Removes Polyfill package reference.
src/Platform/Microsoft.Testing.Extensions.AzureDevOpsReport/Microsoft.Testing.Extensions.AzureDevOpsReport.csproj	Removes Polyfill package reference.
src/Analyzers/MSTest.SourceGeneration/Helpers/SystemPolyfills.cs	Removes local type polyfills in favor of shared `eng/Polyfills.cs`.
src/Analyzers/MSTest.Analyzers/RoslynAnalyzerHelpers/AnalyzerPolyfillExtensions.cs	Adds analyzer-scoped polyfill extensions.
src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj	Removes Polyfill package reference.
src/Analyzers/MSTest.Analyzers.CodeFixes/MSTest.Analyzers.CodeFixes.csproj	Removes Polyfill package reference.
src/Adapter/MSTestAdapter.PlatformServices/Utilities/DeploymentUtility.cs	Replaces `Environment.ProcessId` usage with fallback.
src/Adapter/MSTestAdapter.PlatformServices/Services/TestSourceHost.cs	Replaces `string.Join(char, …)` with string separator overload in updated call site.
src/Adapter/MSTestAdapter.PlatformServices/Services/TestDataSource.cs	Replaces `Enum.Parse<T>` with non-generic overload.
src/Adapter/MSTestAdapter.PlatformServices/PolyfillExtensions.cs	Adds adapter-scoped polyfill extensions (including CTS.CancelAsync for < net8).
src/Adapter/MSTestAdapter.PlatformServices/MSTestSettings.cs	Replaces generic Enum APIs with non-generic overloads for older TFMs.
src/Adapter/MSTestAdapter.PlatformServices/MSTestAdapter.PlatformServices.csproj	Removes Polyfill package reference and Polyfills using.
src/Adapter/MSTestAdapter.PlatformServices/Extensions/MethodInfoExtensions.cs	Replaces `Type.IsGenericMethodParameter` usage with portable logic.
src/Adapter/MSTest.TestAdapter/MSTest.TestAdapter.csproj	Removes Polyfill package reference and Polyfills using.
src/Adapter/MSTest.Engine/MSTest.Engine.csproj	Removes Polyfill package reference.
eng/Polyfills.cs	Adds shared repo-wide polyfill implementations and (conditionally) extension polyfills.
Directory.Packages.props	Removes Polyfill package version entry.
Directory.Build.props	Removes Polyfill MSBuild config and adds compilation of `eng/Polyfills.cs`.

src/Adapter/MSTestAdapter.PlatformServices/PolyfillExtensions.cs

src/Platform/Microsoft.Testing.Platform/Helpers/System/SystemEnvironment.cs

src/Adapter/MSTestAdapter.PlatformServices/Utilities/DeploymentUtility.cs

eng/Polyfills.cs

src/Platform/Microsoft.Testing.Platform/ServerMode/JsonRpc/TcpMessageHandler.cs

Copilot

Pull request overview

Copilot reviewed 73 out of 73 changed files in this pull request and generated 1 comment.

src/Platform/Microsoft.Testing.Extensions.TrxReport/TrxReportEngine.cs

…d param - Add Polyfills.Guard, Polyfills.Ensure, and Polyfills.Polyfill backward- compatible types in eng/Polyfills.cs (guarded by IS_CORE_MTP) to prevent TypeLoadException/MissingMethodException when old extension packages reference these types from the platform assembly via InternalsVisibleTo. - Fix unused cancellationToken parameter in TrxReportEngine constructor for netstandard2.0 builds (addresses PR review comment).

Youssef1313 · 2026-04-07T07:55:29Z

Directory.Build.props

+       CS0436 is suppressed because InternalsVisibleTo causes the same internal polyfill types
+       to be visible from referenced assemblies; the local copy is intentionally preferred. -->
+  <PropertyGroup Condition="'$(Language)' != 'F#'">
+    <NoWarn>$(NoWarn);CS0436</NoWarn>


We shouldn't suppress this.

Instead, we should ensure all polyfills have EmbeddedAttribute.

Youssef1313 · 2026-04-07T07:57:28Z

eng/Polyfills.cs

+{
+    internal static class IsExternalInit;
+
+    [global::System.AttributeUsage(global::System.AttributeTargets.Module | global::System.AttributeTargets.Class | global::System.AttributeTargets.Struct | global::System.AttributeTargets.Constructor | global::System.AttributeTargets.Method | global::System.AttributeTargets.Property | global::System.AttributeTargets.Event | global::System.AttributeTargets.Interface, Inherited = false)]


This should be class, struct, field, and property.
Looks like Field is missing, and Constructor/Method/Event are extra.

Youssef1313 · 2026-04-07T08:00:32Z

eng/Polyfills.cs

+    internal sealed class RequiredMemberAttribute : Attribute { }
+
+    [global::System.AttributeUsage(global::System.AttributeTargets.All, AllowMultiple = true, Inherited = false)]
+    internal sealed class CompilerFeatureRequiredAttribute : Attribute


Let's match the original definition fully, and keep the constants defined in this class.

Copilot AI review requested due to automatic review settings March 24, 2026 10:32

Copilot started reviewing on behalf of Evangelink March 24, 2026 10:33 View session

Copilot AI reviewed Mar 24, 2026

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Evangelink added 3 commits March 25, 2026 09:36

Fixes

a04524d

More issues

34e635a

Address review comments and fix WaitAsync polyfill timeout behavior

3cc434f

Copilot AI review requested due to automatic review settings March 26, 2026 11:19

Copilot started reviewing on behalf of Evangelink March 26, 2026 11:20 View session

Copilot AI reviewed Mar 26, 2026

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src/Platform/Microsoft.Testing.Extensions.TrxReport/TrxReportEngine.cs Show resolved Hide resolved

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[repo-status] Daily Repo Status — March 30, 2026 #7632

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[repo-status] Daily Repo Status — March 31, 2026 #7643

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Evangelink enabled auto-merge April 2, 2026 12:31

Youssef1313 reviewed Apr 7, 2026

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Remove Polyfill NuGet package dependency#7597

Remove Polyfill NuGet package dependency#7597
Evangelink wants to merge 5 commits intomainfrom
remove-polyfill-dependency

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Evangelink commented Mar 24, 2026

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