Remove Polyfill NuGet package dependency

[Evangelink]

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

[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.

[Copilot]

Pull request overview

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