PRI workaround is needed to fix missing file errors

[nickrandolph]

Current behavior

Developers run into errors where the build is complaining about missing files (often xbf files but can also apply to other content files). The fix is to add the following code to the class library.

	<!-- Workaround to avoid including Uno.Toolkit.UI XBFs in the PRI file -->
	<Target Name="AdjustGetPackagingOutput1" AfterTargets="GetMrtPackagingOutputs">
		<Message Importance="high" Text="Applying NuGet packaging workaround for dependent PRI files exclusion" />
		<ItemGroup>
			<_OtherPriFiles Include="@(PackagingOutputs)" Condition="'%(Extension)' == '.pri' and ('%(PackagingOutputs.ReferenceSourceTarget)' == 'ProjectReference' or '%(PackagingOutputs.NugetSourceType)'=='Package')" />
			<PackagingOutputs Remove="@(_OtherPriFiles)" />
		</ItemGroup>
	</Target>
	<Target Name="AdjustGetPackagingOutput2" BeforeTargets="AddPriPayloadFilesToCopyToOutputDirectoryItems">
		<Message Importance="high" Text="Applying NuGet packaging workaround for dependent PRI files exclusion" />
		<ItemGroup>
			<_OtherPriFiles1 Include="@(_ReferenceRelatedPaths)" Condition="'%(Extension)' == '.pri' and ('%(_ReferenceRelatedPaths.ReferenceSourceTarget)' == 'ProjectReference' or '%(_ReferenceRelatedPaths.NugetSourceType)'=='Package')" />
			<_ReferenceRelatedPaths Remove="@(_OtherPriFiles1)" />
			<_OtherPriFiles2 Include="@(ReferenceCopyLocalPaths)" Condition="'%(Extension)' == '.pri' and ('%(ReferenceCopyLocalPaths.ReferenceSourceTarget)' == 'ProjectReference' or '%(ReferenceCopyLocalPaths.NugetSourceType)'=='Package')" />
			<ReferenceCopyLocalPaths Remove="@(_OtherPriFiles2)" />
		</ItemGroup>
	</Target>

Expected behavior

No response

How to reproduce it (as minimally and precisely as possible)

No response

Workaround

No response

Works on UWP/WinUI

None

Environment

No response

NuGet package version(s)

No response

Affected platforms

No response

IDE

No response

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

Suggestion is to apply this workaround either as a .target in uno.winui, or as a separate nuget package

[jeromelaban]

I opened an issue in microsoft/microsoft-ui-xaml#8857

[nickrandolph]

@jeromelaban in the meantime, did we want to include the workaround within Uno?

[jeromelaban]

I don't think we should be including it, as it may cause double inclusion. I think the route is still to make a separate package.