Emacs Lisp buffer not running font lock mode until opened by user

My problem is I am opening a buffer using (set-buffer (find-tag-noselect (current-word))) and then I try to copy some text out of that buffer. The text that I get back has only the properties (fontified nil). find-tag-noselect automatically opens the buffer found in the TAGS file but it seems it does not run the font lock mode over it. When I manually switch to this buffer after it has been opened and then run the function again when it copies the text it has all the co开发者_开发百科rrect text properties attached. So what do I need to do to have this buffer completely initialized so that the correct syntax highlighting will be copied in?

(defvar newline-string "
")

(defun get-initial-indent-regexp-python()
  "Gets the initial amount of spaces for the function we are looking at, does not account for tabs"
  (concat "^" (get-current-indent-string) (concat "[^ #" newline-string "]")))


(defun get-end-of-function-python(spaces-regex)
  "Gets the point at the end of a python block"
  (save-excursion
    (forward-line 1)
    (while (and (not (looking-at spaces-regex)) (equal (forward-line 1) 0)))
    (point)))

(defun get-point-at-end-of-function ()
  "This might be better served checking the major mode."
  (setq extension (file-name-extension (buffer-file-name)))
  (if (equal extension "py")
      (get-end-of-function-python (get-initial-indent-regexp-python))))
(defun inline-function ()
  "Must change to overlays, be able to toggle visibility"
  (interactive)
  (let (text indent-string)
                    ; clean all overlays without attached buffer
    (save-excursion
      (set-buffer (find-tag-noselect (current-word)))
      (setq text (buffer-substring (point) (get-point-at-end-of-function))))

    (setq text (concat newline-string text))
    (save-excursion
      (move-end-of-line nil)
      (let (overlay)
    (setq overlay (make-overlay (point) (+ (point) 1) (current-buffer)))
    (overlay-put overlay 'display text)
    (setq inline-func-overlays (cons overlay inline-func-overlays))))))

What's happening is that font-lock is done on-the-fly, so only the displayed parts of the buffer get "fontified". If you want/need to overrule this optimization, you need different functions depending on the circumstance (depending on how font-lock happens to be configured). We should add a new font-lock-ensure-fontified function for that, but in the mean time, you can take ps-print-.el as an example:

(defun ps-print-ensure-fontified (start end)
  (cond ((and (boundp 'jit-lock-mode) (symbol-value 'jit-lock-mode))
     (jit-lock-fontify-now start end))
    ((and (boundp 'lazy-lock-mode) (symbol-value 'lazy-lock-mode))
     (lazy-lock-fontify-region start end))))

I'm not exactly sure what you're trying to do, but set-buffer does not display the buffer, so its effect ends when the current command terminates. It's generally useful only for temporary buffer switches inside a function and I guess this is the reason it doesn't run font-lock on the buffer. When you manually go to the buffer you're probably using a different function - switch-to-buffer.

Try explicitly calling 'font-lock-fontify-buffer'.