Fix Unix pipe timeout test failure by handling ConnectionReset exception

.github/copilot-instructions.md

@@ -99,6 +99,9 @@ When making change to resource files, you MUST:
 - Public API for MSTest and Microsoft.Testing.Platform MUST NOT use `init` accessors.
   - Exception: Existing APIs in Microsoft.Testing.Platform, because changing them right now would be a breaking change. However, we MUST NOT introduce **new** APIs using `init` accessors.
   - IMPORTANT: Make sure to apply this rule strictly both during PR review and when working on code changes.
+- Every API marked with `[Experimental]` MUST include this sentence in its XML documentation `<remarks>`: `This API is experimental. It may change, break, or be removed at any time without notice.` Documentation tooling does not reliably surface the attribute itself.
+  - Add the sentence in a `<para>` when `<remarks>` already contains other text; otherwise, add a new `<remarks>` block.
+  - Apply this rule to experimental members as well as types.
 
 ## Testing Guidelines
 

.github/workflows/shared/build-failure-analysis-fetch.md

@@ -504,11 +504,10 @@ jobs:
           # than guessing its artifact name from its display name. Artifact
           # naming is configurable per job group and does not necessarily match
           # the timeline display name. Name matching reported healthy legs as
-          # missing on real builds — every macOS failure, and every
-          # `msbuild_cache_seed` job. Arcade's
+          # missing on real builds — including every macOS failure. Arcade's
           # `Publish logs` task record answers the question directly, so no
           # spelling has to be inferred. A failed job carrying no such task
-          # (the `Detect changed paths` classifier, the cache-seed stage) does
+          # (the `Detect changed paths` classifier) does
           # not publish logs at all and is not treated as a missing leg.
           #
           # `canceled` and `abandoned` legs count alongside `failed`: they also

Directory.Build.props

@@ -11,41 +11,6 @@
     <ExtrasEnableEmbeddedResourceCodeGenerator>false</ExtrasEnableEmbeddedResourceCodeGenerator>
   </PropertyGroup>
 
-  <!-- MSBuildCache only supports clean, Windows graph builds. Keep it opt-in so regular and incremental builds are unchanged. -->
-  <PropertyGroup>
-    <MSBuildCacheEnabled Condition="'$(MSBuildCacheEnabled)' == ''">false</MSBuildCacheEnabled>
-  </PropertyGroup>
-
-  <PropertyGroup Condition="'$(MSBuildCacheEnabled)' == 'true'">
-    <!-- Change this value to invalidate all existing testfx cache entries. -->
-    <!--
-      Azure Pipeline cache entries are immutable. Debug and Release are built in parallel in CI, and some
-      configuration-independent projects otherwise race to publish the same selector/output entries. Keep the
-      configurations in separate universes so one seed cannot fail the other with PipelineCacheItemAlreadyExists.
-    -->
-    <MSBuildCacheCacheUniverse Condition="'$(MSBuildCacheCacheUniverse)' == ''">testfx-v1-$(Configuration)</MSBuildCacheCacheUniverse>
-    <MSBuildCacheLocalCacheRootPath Condition="'$(MSBuildCacheLocalCacheRootPath)' == ''">$(RepoRoot)artifacts\msbuild-cache</MSBuildCacheLocalCacheRootPath>
-    <MSBuildCacheLocalCacheSizeInMegabytes Condition="'$(MSBuildCacheLocalCacheSizeInMegabytes)' == ''">20480</MSBuildCacheLocalCacheSizeInMegabytes>
-    <!--
-      By default MSBuildCache hardlinks every output into its content-addressable store and marks it read-only,
-      both when it materializes a cache hit and when it ingests the outputs of a cache miss. That leaves the whole
-      output tree read-only, so the Arcade restore/sign/pack pass that runs after the cached graph build cannot
-      rewrite files such as artifacts\bin\**\*.deps.json or the generated src\Package\MSTest.Sdk\Sdk\Sdk.props,
-      and fails with UnauthorizedAccessException. Clearing the read-only attribute is not a valid workaround: the
-      output file and the cache entry share an inode, so writing through it corrupts the cache and can silently
-      rewrite a same-content output belonging to another project.
-
-      Matching every output with '\**' switches MSBuildCache to CopyNoVerify, which copies instead of hardlinking
-      and leaves the outputs writable. It costs extra I/O, and it relaxes duplicate-output detection so that two
-      projects may write the same path when the content is identical - producing that path with different content
-      is still an error. The pattern participates in the fingerprint, so changing it invalidates every cache entry
-      until the next main-branch seed repopulates them.
-    -->
-    <MSBuildCacheIdenticalDuplicateOutputPatterns>$(MSBuildCacheIdenticalDuplicateOutputPatterns);\**</MSBuildCacheIdenticalDuplicateOutputPatterns>
-    <!-- Visual Studio telemetry writes outside the repository after the project that launched it has finished. -->
-    <MSBuildCacheAllowFileAccessAfterProjectFinishFilePatterns>$(MSBuildCacheAllowFileAccessAfterProjectFinishFilePatterns);$(WinDir)\**;\**\ApplicationInsights.config;\**\AppData\Local\Microsoft\VSApplicationInsights\**;\**\AppData\Local\Microsoft\Windows\INetCache\**</MSBuildCacheAllowFileAccessAfterProjectFinishFilePatterns>
-  </PropertyGroup>
-
   <!-- Language configuration -->
   <PropertyGroup>
     <!-- default to allowing all language features -->

Directory.Packages.props

@@ -11,15 +11,6 @@
     <!-- It also needs to be added to nuspec manually (for projects that use nuspec) so that the new version flows to consumers -->
     <CentralPackageTransitivePinningEnabled>false</CentralPackageTransitivePinningEnabled>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(MSBuildCachePackageEnabled)' == 'true'" Label="Build dependencies">
-    <MSBuildCachePackageName Condition="'$(TF_BUILD)' != ''">Microsoft.MSBuildCache.AzurePipelines</MSBuildCachePackageName>
-    <MSBuildCachePackageName Condition="'$(MSBuildCachePackageName)' == ''">Microsoft.MSBuildCache.Local</MSBuildCachePackageName>
-    <MSBuildCachePackageVersion>0.1.328-preview</MSBuildCachePackageVersion>
-  </PropertyGroup>
-  <ItemGroup Condition="'$(MSBuildCachePackageEnabled)' == 'true'" Label="Build dependencies">
-    <GlobalPackageReference Include="$(MSBuildCachePackageName)" Version="$(MSBuildCachePackageVersion)" />
-    <GlobalPackageReference Include="Microsoft.MSBuildCache.SharedCompilation" Version="$(MSBuildCachePackageVersion)" />
-  </ItemGroup>
   <PropertyGroup Label="Product dependencies">
     <!-- AspireHostingTestingVersion is consumed by the build and baked into the shipped MSTest.Sdk
          template. It MUST be kept in sync with the literal Aspire.Hosting.Testing PackageVersion

NuGet.config

@@ -38,8 +38,6 @@
       <package pattern="*" />
     </packageSource>
     <packageSource key="dotnet-public">
-      <package pattern="Microsoft.MSBuildCache.Local" />
-      <package pattern="Microsoft.MSBuildCache.SharedCompilation" />
       <package pattern="*" />
     </packageSource>
     <packageSource key="dotnet-tools">