(defun locate-dominating-file (file name)
"Look up the directory hierarchy from FILE for a file named NAME.
Stop at the first parent directory containing a file NAME,
-and return the directory. Return nil if not found."
+and return the directory. Return nil if not found.
+
+This function only tests if FILE exists. If you care about whether
+it is readable, regular, etc., you should test the result."
;; We used to use the above locate-dominating-files code, but the
;; directory-files call is very costly, so we're much better off doing
;; multiple calls using the code in here.