Function dir_size_skipping_git 

pub fn dir_size_skipping_git<'a, I: IntoIterator<Item = &'a Path>>(
    roots: I,
) -> u64

Sum the real on-disk size of every file under roots, skipping any .git/ subtree. Hardlinks are deduplicated per-walk by (dev, ino) on Unix. Silently ignores missing roots so callers don’t have to pre-filter.