I have a feeling the particular approach in 50feda0 is non-viable. It is not necessarily a safe assumption that any local relative path in command arguments to execute inside a Docker container which matches a real local relative path on the host should be transformed, especially if, for example, --workdir is being changed and the path is meant to refer to a known path in the container which "just so happens" to match one on the host.

I think the solution must constrain itself to the specific inputs known to potentially contain local relative paths, requires and requirement_installer_args.