Prevent .NET Core 2.0 from leaving files in /tmp on RHEL7

Question

Edit: Martin provides a link below to a defect, which is now fixed and released.

I am a university student. I would like to use .NET Core for my coursework. To do so, my code needs to compile and run on the department Linux cluster, because that is what my instructors test my submissions on.

My sysadmin installed the recently-released .NET Core 2.0 RHEL package for me on a trial basis. I created, built, and ran the sample CLI projects Microsoft provides, and they worked. But my sysadmin was displeased because dotnet created at least one file in (global) /tmp, which remained there after I logged off.

-rw------- myuser mygroup /tmp/.NETCoreApp,Version=v2.0.AssemblyAttributes.cs

In principle, he'd prefer dotnet not create any files in /tmp that it doesn't clean up when its process is done. More than that, when he tried to build Microsoft's samples himself, it failed; dotnet tried to access the above file, which his user did not have read permissions for!

Ideally, dotnet wouldn't create any files with a lifetime different from the project it is building. To achieve this, any such files could live in the project directory — maybe under the bin subdirectory, so that a clean will purge them. Is there a way to make dotnet write these files there instead? Otherwise, can it least use transient filenames, to avoid the permissions conflict we encountered?

Whatever the solution is, it has to be systemwide, and it cannot depend on the good behavior of users. So something like asking the user to set $TMPDIR will not work.

Answer 1

The easiest way would be to set the TMPDIR environment variable to a different location as MSBuild uses it to construct the path.

Another way to make msbuild use a local path for this file is to add a target like this to the csproj file:

<Target Name="SetTFMAssemblyAttributesPath"
      BeforeTargets="GenerateTargetFrameworkMonikerAttribute">
  <PropertyGroup>
    <TargetFrameworkMonikerAssemblyAttributesPath>$(IntermediateOutputPath)$(TargetFrameworkMoniker).AssemblyAttributes$(DefaultLanguageSourceExtension)</TargetFrameworkMonikerAssemblyAttributesPath>
  </PropertyGroup>
  <ItemGroup>
    <!-- GenerateTargetFrameworkMonikerAttribute doesn't add to @(FileWrites) for the global path -->
    <FileWrites Include="$(TargetFrameworkMonikerAssemblyAttributesPath)" />
  </ItemGroup>
</Target>

This will put it into the IntermediateOutputPath which is obj/{Debug/Release}/{TargetFramework}/. The added FileWrites item allows it to be cleaned on dotnet clean, which is not done for the global location to avoid race conditions during clean.

You can create a Directory.Build.targets file in your user directory / in the directory hierarchy your projects are in to wire up the target to all projects (unless they don't already contain a file with this name). Just surround the target with a <Project> element for this file.

There is a GitHub issue on changing the default location.