Actually, the Git data model supports empty directories, however, the index doesn't since it only maps names to files but not to directories. You can even create a commit with a root directory using --allow-empty, and it will use the hardcoded empty tree object (4b825dc642cb6eb9a060e54bf8d69288fbee4904).

yep! Had to check to be sure:

    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.02s
     Running `target/debug/tvc decompress f854e0b307caf47dee5c09c34641c41b8d5135461fcb26096af030f80d23b0e5`

=== args === decompress f854e0b307caf47dee5c09c34641c41b8d5135461fcb26096af030f80d23b0e5 === tvcignore === ./target ./.git ./.tvc

=== subcommand === decompress ------------------ tree ./src/empty-folder e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 blob ./src/main.rs fdc4ccaa3a6dcc0d5451f8e5ca8aeac0f5a6566fe32e76125d627af4edf2db97