bug#16804: 24.3.50; [PATCH] fix with-silent-modifications

[Leo Liu]

On 2014-02-19 22:28 +0800, Stefan Monnier wrote:
> Yes, that's the general understanding I already had, but the particulars
> are important as well.  Could you give details of the problem you
> bump into?  Maybe a backtrace showing the sequence of calls that leads
> to using buffer-file-name while it's rebound?

1. Emacs -q and eval the following code

;;;--------------------------------
(setq eldoc-idle-delay 0.2)
(add-hook 'js2-mode-hook #'bug)

(defun bug ()
  (setq-local eldoc-documentation-function #'bug-1)
  (setq js2-idle-timer-delay 0.2)
  (when buffer-file-name
    (eldoc-mode 1)))

(defun bug-1 ()
  (message "::%S::" buffer-file-name))
;;;--------------------------------

2. open a large javascript file (a few hundred lines) and switch its
   mode to js2-mode. For example

   backbone.js from git@github.com:jashkenas/backbone.git will do
   (sorry github is blocked today by my country so I cannot access it
   myself)

3. edit the file and see ::nil:: echoed

This means if function bug-1 needs buffer-file-name, directly or
indirectly, it won't work.

Leo