awesome-tags.el

(defun locate-tags-file (&optional dir)
  "Locate a TAGS or TAGS.gz file in DIR or a parent directory."
  (let ((dir (or dir default-directory))
        (tag-files '("TAGS" "TAGS.gz"))
        (tag-dir)
        (tag-file))

    (while (and (not tag-file) tag-files)
      (let ((potential-file (car tag-files)))
        (setq tag-files (cdr tag-files))
        (when (setq tag-dir (locate-dominating-file dir potential-file))
          (setq tag-file (concat tag-dir
                                 (if (not (equal (substring dir -1) "/")) "/" "")
                                 potential-file)))))
    tag-file))

(defmacro with-project-tags (&rest body)
  "Temporarily bind tags file to the closest tags file, then execute BODY."
  `(let* ((local-tags (locate-tags-file))
          (tags-file-name (or locate-tags-file tags-file-name))
          (tags-revert-without-query t)
          (tags-table-list (if local-tags nil tags-table-list)))
     ,@body))

(defadvice find-tag (around use-local-tags first activate)
  "Force find-tag to use the closest tag file."
  (with-project-tags
   ad-do-it))

(defadvice find-tag-regexp (around use-local-tags first activate)
  "Force find-tag-regexp to use the closest tag file."
  (with-project-tags
   ad-do-it))

(defadvice tags-apropos (around use-local-tags first activate)
  "Force tags-apropos to use the closest tag file."
  (with-project-tags
   ad-do-it))