Function add_worktree 

pub fn add_worktree(
    repo: &Repository,
    branch_name: &str,
    explicit_worktree_name: Option<&str>,
    branch_type: BranchType,
    base_branch: Option<&str>,
    lock: bool,
) -> Result<WorktreeDescriptor>

Create a new worktree for the given branch.

The worktree directory is placed under the workon root (see workon_root). Branch names containing / are supported; parent directories are created automatically and the worktree is named after the final path component.

When explicit_worktree_name is Some, that value is used as the worktree directory name and filesystem path instead of deriving it from branch_name. This allows the worktree directory and the branch to have different names.

Branch types

• BranchType::Normal — uses an existing local branch, creates a local branch from a matching remote tracking branch (setting upstream automatically), or creates a new branch from base_branch (or HEAD if base_branch is None).
• BranchType::Orphan — creates an independent branch with no shared history, seeded with an empty initial commit.
• BranchType::Detached — creates a worktree with a detached HEAD pointing to the current HEAD commit.