Handle empty package enumeration during COM manual activation

[Ratin Gao (RatinCN)]

📖 Description

The initial sizing call to FindPackagesByPackageFamily returns ERROR_INSUFFICIENT_BUFFER when matching packages exist, but can validly return ERROR_SUCCESS with a count of zero when no package is registered for the current identity.

The current code passes that success result to a failure-only WIL macro, causing the calling process to CRASH through FAIL_FAST instead of receiving a normal HRESULT. This change accepts the valid empty result and lets the existing control flow return ERROR_PACKAGE_NOT_REGISTERED_FOR_USER instead.

The registered-package path and propagation of other Win32 errors remain unchanged. This is consistent with the handling established in #2922.

For the SYSTEM scenario in #4944, this prevents the direct CRASH caused by FAIL_FAST, but does not add OutOfProc COM support, enumerate packages registered to other users, or use staged packages.

🔗 References

• Related to COM API client FindPackages function fails in CreateInstance method when run under LOCAL SYSTEM Context. Unable to find WindowsPackageManagerServer.exe #4944; addresses the FAIL_FAST CRASH only.
• Similar empty-result handling was introduced in Fix GetFullNameFromFamilyName for non-elevated context #2922.
• FindPackagesByPackageFamily documentation

🔍 Validation

• Reproduced the existing SYSTEM CRASH with 0xC0000409 (FAIL_FAST).
• Confirmed that the API returns ERROR_SUCCESS with a package count of zero under SYSTEM.
• Built Microsoft.Management.Deployment.OutOfProc for x64 Debug with the production package family and CLSIDs.
• Verified the modified DLL as a normal user: exit code 0 and 237 packages enumerated.
• Verified the modified DLL under SYSTEM: caught COMException with HRESULT 0x80073D35; exit code 0 with no process crash.

✅ Checklist

• Signed the Contributor License Agreement
• Linked to an issue
• Updated Release Notes (not applicable)
• Updated documentation (not applicable)
• Updated Copilot instructions (not applicable)

📋 Issue Type

• Bug fix
• Feature
• Task

Microsoft Reviewers: Open in CodeFlow

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[JohnMcPMS]

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[JohnMcPMS]

This code is not relevant for SYSTEM use, but the change appears righteous for standard users.

[Ratin Gao (RatinCN)]

This code is not relevant for SYSTEM use, but the change appears righteous for standard users.

Agreed. SYSTEM is not supported for this OutOfProc path and was only used to reproduce the issue. This change handles the valid empty result by returning ERROR_PACKAGE_NOT_REGISTERED_FOR_USER instead of crashing through FAIL_FAST.