Function get_modifications 

pub(crate) fn get_modifications(
    pristine: &Directory<CustomMetadata>,
    current: &Directory<CustomMetadata>,
    pristine_leaves: &[Leaf<CustomMetadata>],
    current_leaves: &[Leaf<CustomMetadata>],
    new: &Directory<CustomMetadata>,
    current_path: PathBuf,
    diff: &mut Diff,
) -> Result<()>