Cannot use embeded PackageReadmeFile when using snupkg for symbols

[meziantou]

Details about Problem

NuGet product used: dotnet.exe

Product version: 6.0.0-preview.3.21201.4

Worked before? If so, with which NuGet version: 🤷‍♀️

Repro steps and/or sample project

• dotnet new classlib
• Create a non-empty readme.md file
• Edit the csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <RootNamespace>New_folder</RootNamespace>        
    <IncludeSymbols>true</IncludeSymbols>
    <SymbolPackageFormat>snupkg</SymbolPackageFormat>
  </PropertyGroup>
  
  <PropertyGroup>
    <PackageReadmeFile>readme.md</PackageReadmeFile>
</PropertyGroup>

<ItemGroup>
    <None Include="readme.md" Pack="true" PackagePath="\" />
</ItemGroup>

</Project>

• dotnet pack

Microsoft (R) Build Engine version 16.10.0-preview-21181-07+073022eb4 for .NET
Copyright (C) Microsoft Corporation. All rights reserved.

  Determining projects to restore...
  All projects are up-to-date for restore.
  You are using a preview version of .NET. See: https://aka.ms/dotnet-core-preview
  NewFolder -> C:\Users\mezia\Desktop\NewFolder\bin\Debug\net6.0\NewFolder.dll
  Successfully created package 'C:\Users\mezia\Desktop\NewFolder\bin\Debug\NewFolder.1.0.0.nupkg'.
C:\Program Files\dotnet\sdk\6.0.100-preview.3.21202.5\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(221,5): error NU5039: The readme file 'readme.md' does not exist in the package. [C:\Users\mezia\Desktop\NewFolder\NewFolder.csproj]

Additional information

• It can generate the package if you remove <SymbolPackageFormat>
• There is no issue with the <PackageIcon> nor <PackageLicenseFile> properties, so it seams to be only for the PackageReadmeFile

[BlackGad]

snupkg package format strongly limited with content filter by extensions (*.pdb and some more)

[zkat]

We need to look into what we do here for licenses.

[MarkStega]

Confirming the same issue with a Net5 project and "Microsoft (R) Build Engine version 16.10.0-preview-21175-01+afd0b6210 for .NET" as the build engine.

[campersau]

Maybe this is check !PackageTypes.Contains(PackageType.SymbolsPackage) which is already in ValidateLicenseFile
and ValidateIconFile needs to be added to ValidateReadmeFile too.

Also in PackageMetadataXmlExtensions the readme element is always added whereas the elements for licenseUrl and icon are not because of the same check here !PackageTypes.Contains(PackageType.SymbolsPackage).