Function rename_current 

pub fn rename_current(
    branch_name: &str,
    repo: Option<&Repository>,
) -> Result<()>

Rename the current local branch.

Mirrors git branch -m <branch_name> semantics: the rename is not forced, so it fails when the target branch already exists.

Errors

• Repository discovery fails.
• HEAD is detached or the current branch cannot be resolved.
• The current local branch cannot be found.
• The branch rename fails.