from TAGS if present."
(let ((result-tags (copy-sequence tags)))
(dolist (tag-change tag-changes)
- (let ((tag (and (not (string= tag-change ""))
+ (let ((tag (and (not (string-empty-p tag-change))
(substring tag-change 1))))
(cl-case (aref tag-change 0)
(?+ (unless (member tag result-tags)