Note that (:root "../") should be the same as (:root) since the root's parent is itself (if defined at all).
If you want getcwd's parent, you should probably use (parent-directory-pathname (getcwd)). truename will presumably merge with *default-pathname-defaults* which can be something altogether different (and itself a relative pathname).
Note that (:root "../") should be the same as (:root) since the root's parent is itself (if defined at all).
If you want getcwd's parent, you should probably use (parent- directory- pathname (getcwd)). truename will presumably merge with *default- pathname- defaults* which can be something altogether different (and itself a relative pathname).