Fix workload advertising manifest extraction with WiX v4+ built MSIs

[Copilot]

On MSI-based installs, dotnet workload install fails to refresh the microsoft.net.workloads advertising manifest and silently falls back to stale manifests:

Failed to update the advertising manifest microsoft.net.workloads: Could not find a part of the path 'C:\Users...\AppData\Local\Temp\0nwvv1w2.pwu\msi\dotnet\sdk-manifests'.

Root cause

Workload set packages don't ship a data\extractedManifest folder (manifest MSI packages do), so WindowsMsiManifestInstaller.ExtractManifestAsync falls back to an administrative install — ACTION=ADMIN TARGETDIR=<tmp>\msi — and then reads a hardcoded <tmp>\msi\dotnet\sdk-manifests.

Workload MSI generation moved from WiX v3 to WiX v5, which changed the MSI Directory table and therefore the admin-image layout:

	Directory table	Admin image path
WiX v3	ProgramFiles64Folder | TARGETDIR | .	<tmp>\msi\dotnet\sdk-manifests\...
WiX v5	ProgramFiles6432Folder | ProgramFiles64Folder | . ProgramFiles64Folder | TARGETDIR | PFiles64	<tmp>\msi\PFiles64\dotnet\sdk-manifests\...

(Confirmed by exporting the Directory table from the shipped preview.6 and preview.7 workload MSIs.) During an administrative install directories are resolved from TARGETDIR using DefaultDir, so the v3 . collapsed away while v5 adds a PFiles64 level. The hardcoded path then throws DirectoryNotFoundException. Zip/tar installs are unaffected — they never touch an MSI.

Changes

• WindowsMsiManifestInstaller: new FindExtractedManifestFolder helper locates sdk-manifests by name under the admin-install target rather than assuming a fixed depth, so both layouts work (and PFiles vs PFiles64 across architectures). The existing "descend two single-child levels" behavior is unchanged.
• Error surface: when the folder can't be located, the existing ExpectedSingleManifest GracefulException is raised instead of an unhandled DirectoryNotFoundException.
• Tests: cover the WiX v3 layout, the WiX v4+ layout, and the missing/not-found cases.

-var manifestsFolder = Path.Combine(msiExtractionPath, "dotnet", "sdk-manifests");
-
-string? manifestFolder = null;
-string? manifestsFeatureBandFolder = Directory.GetDirectories(manifestsFolder).SingleOrDefault();
-if (manifestsFeatureBandFolder != null)
-{
-    manifestFolder = Directory.GetDirectories(manifestsFeatureBandFolder).SingleOrDefault();
-}
+string? manifestFolder = FindExtractedManifestFolder(msiExtractionPath);

Notes for reviewers

• The changed source file and its test file are Windows-only (Compile Remove elsewhere), so they compile and run on Windows CI only.
• A complementary fix in arcade — having WorkloadSetMsi emit data\extractedManifest like WorkloadManifestMsi does — would remove the admin-install dependency entirely, but is out of scope for this repo.

• Fixes NETSDKE2E][Regression] With .NET 11.0.100-preview.7.26379.122 installed by exe installer, failed to update the advertising manifest microsoft.net.workloads: Could not find a part of the path %appdata%\Local\Temp\2igunvgq.qkc\msi\dotnet\sdk-manifests when installing workloads #55548

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[joeloff]

This is fine. WiX4 introduced a new StandardDirectory that is used to eliminate authoring custom conditionals to select the appropriate ProgramFiles folder. This adds an additional entry in the directory table which is what the SDK is hitting. Since we have a mix of both v3 and v4+ built installers for workloads, we should take this fix

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[Copilot]

Pull request overview

Fixes dotnet workload install advertising-manifest refresh on Windows MSI-based installs when the admin-image layout differs (WiX v4+/v5 adding a PFiles* directory level), avoiding a hardcoded msi\dotnet\sdk-manifests assumption.

Changes:

• Updates WindowsMsiManifestInstaller.ExtractManifestAsync to locate the extracted sdk-manifests folder via a new helper instead of a fixed path.
• Adds FindExtractedManifestFolder to search for the admin-image manifest layout across WiX variants and return null when not found.
• Adds Windows-only tests covering WiX v3 layout, WiX v4+ layout, and missing-manifest cases.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/Cli/dotnet/Commands/Workload/Install/WindowsMsiManifestInstaller.cs	Adds helper to locate sdk-manifests under MSI admin-image output and uses it during extraction.
test/dotnet.Tests/CommandTests/Workload/Install/GivenAWindowsMsiManifestInstaller.cs	Adds unit tests validating the helper against WiX v3 vs v4+ layouts and not-found behavior.