 or an <a href="#def_object">object</a>
that can be recursively dereferenced to a tree object.
Dereferencing a <a href="#def_commit_object">commit object</a> yields the
tree object corresponding to the <a href="#def_revision">revision</a>'s
top <a href="#def_directory">directory</a>.
The following are all tree-ishes:
a <a href="#def_commit-ish">commit-ish</a>,
a tree object,
a <a href="#def_tag_object">tag object</a> that points to a tree object,
a tag object that points to a tag object that points to a tre