Publish fails from VS, because `project.assets.json` not found

Describe the bug When I create a new Solution with an empty WinUI 3 Desktop app in VS 16.10.2. The project works both in Debug and Release configuration without error. However, when I use VS to create MSIX packages, the creation fails.

1>------ Publish started: Project: App10 (Package), Configuration: Release x86 ------
1>Determining projects to restore...
1>Restored C:\Users\Marvin\source\repos\App10\App10\App10.csproj (in 478 ms).
1>Assets file 'C:\Users\Marvin\source\repos\App10\App10\obj\wappublish\win10-x86\project.assets.json' not found. Run a NuGet package restore to generate this file.
========== Publish: 0 succeeded, 1 failed, 0 skipped ==========
========== Package: 0 succeeded, 2 failed ===========

This seems indeed correct, as the file project.assets.json it is looking for is in the path C:\Users\Marvin\source\repos\App10\App10\obj\wappublish\win-x86\project.assets.json (Notice the win-x86 instead of win10-x86)

Can I tell VS to look in the right directory?

Project source App10.zip

Build bin logs logs.zip

Version Info

NuGet package version:

WinUI 3 - Project Reunion 0.5: 0.5.7

Windows app type:

UWP	Win32
	Yes

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
May 2021 Update (19043)	Yes
October 2020 Update (19042)
May 2020 Update (19041)
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context This is how I created MSIX packages in VS: Right click in Solution Explorer on the Packaging project -> Publish -> Create App Packages. I select Sideloading, disable automatic updates, select my certificate for signing, select Release (x86) only. Generate app bundle “Always”.

[edwardskrod]

We are going to try to take this for 16.10.4. I will keep you posted.

[edwardskrod]

@Marv51 Thanks for reporting this issue. We fixed this in 16.11 Preview 3, which will ship in the middle of July. https://visualstudio.microsoft.com/vs/preview/

As a workaround, you can build and publish your application from the command line.