[Bug]: Satellite assemblies with un-predefined cultures are not copied correctly into depended projects

[PopSlime]

Issue Description

Satellite assemblies with un-predefined cultures in a project are not copied correctly into the projects that depends on it.

Steps to Reproduce

Assume that yue is not a predefined language in the system.

1. Create a project (Project A) with two resources named Test.resx and Test.yue.resx respectively.
2. Add the following metadata into Project A:

   <PropertyGroup>
   	<RespectAlreadyAssignedItemCulture>True</RespectAlreadyAssignedItemCulture>
   </PropertyGroup>
   <ItemGroup>
   	<EmbeddedResource Update="Test.resx">
   		<Generator>ResXFileCodeGenerator</Generator>
   	</EmbeddedResource>
   	<EmbeddedResource Update="Test.yue.resx">
   		<Culture>yue</Culture>
   		<LogicalName>Test.yue.resources</LogicalName>
   	</EmbeddedResource>
   </ItemGroup>

3. Create another project (Project B) that has a project reference to Project A.
4. Create another project (Project C) that has a project reference to Project B.
5. Build the projects.

Expected Behavior

The satellite assembly for the culture yue is correctly copied into Project B and Project C, and also written into their .deps.json.

Actual Behavior

• The satellite assembly for the culture yue is not copied into Project C at all.
• The .deps.json in both Project B and Project C do not include the satellite assembly for the culture yue.

Analysis

Suspicious related method: ReferenceTable.FindSatellites()

msbuild/src/Tasks/AssemblyDependency/ReferenceTable.cs

Line 974 in 4bb8d03

if (CultureInfoCache.IsValidCultureString(cultureName))

This method cannot find satellite assemblies with unusual cultures because it is still checking the satellite directory name against CultureInfoCache only.

Related issues and PRs:

• [Bug]: Valid BCP 47 tags in the resource file name not recognized #9954
  (Fixed by Update AssignCulture Task to support existing Culture metadata #10026)

Versions & Configurations

MSBuild version: 17.11.2.32701

[PopSlime]

Switching to another resource workflow as this issue seems to be put aside for now