Function publication_store 

pub fn publication_store(
    project_state: &Path,
    repo: &Path,
) -> Result<PathBuf, String>

The private repository publications are built in: a bare repository in the project’s state directory that borrows the project’s objects (objects/info/alternates), so the tip a publication is parented on resolves there while the held-out tests themselves never enter the project’s repository. Every attempt can read that repository’s refs and objects (git show, git fsck --unreachable, a script a check runs); none can read the state directory.

Errors

The repository cannot be created, or the project’s objects not found.