Ever came across this error on publishing a dotnet project that includes libs of your own:

error NETSDK1097: It is not supported to publish an application to a single-file without specifying a RuntimeIdentifier. You must either specify a RuntimeIdentifier or set PublishSingleFile to false.

E.g. using urho.net with this vs-code setup:

                "publish",
                "-c","Release",
                "-r","linux-x64",
                "--self-contained","true",
                "/property:PublishFlavor=linux-x64",
                "/property:PublishSingleFile=true",
                "/property:PublishTrimmed=true",
                "/property:DefineConstants=_DESKTOP_PUBLISHED_BINARY_",
                "${workspaceFolder}/${workspaceFolderBasename}.csproj",
                "/property:GenerateFullPaths=true",
                "/consoleloggerparameters:NoSummary"

Adding this to the referenced project's csproj fixed the issue:

  <PropertyGroup>
    <RuntimeIdentifiers>win-x64;osx-x64;linux-x64</RuntimeIdentifiers>
  </PropertyGroup>

I'm quite sure the problem is that I had created the subprojects as console-application and not as library and that this is actually the problem....

Btw, found a hint on how to handle this here