Function describe

pub fn describe<'name, Find, E>(
    commit: &oid,
    find: Find,
    _: Options<'name>,
) -> Result<Option<Outcome<'name>>, Error<E>>
where
    Find: for<'b> FnMut(&oid, &'b mut Vec<u8>) -> Result<Option<CommitRefIter<'b>>, E>,
    E: Error + Send + Sync + 'static,

Given a commit id, traverse the commit graph and collect candidate names from the name_by_oid mapping to produce an Outcome, which converted into_format() will produce a typical git describe string.

Note that the name_by_oid map is returned in the Outcome, which can be forcefully returned even if there was no matching candidate by setting fallback_to_oid to true.