autorevert and excessive verbosity.

[Luc Teirlinck]

If global-auto-revert-mode _and_ global-auto-revert-non-file-buffers
are enabled, the buffer-menu updates automatically every
auto-revert-interval seconds.  A buffer-stale-function which does that
should _never_ cause auto-revert-mode to print revert messages even if
auto-revert-verbose is t.  Otherwise Emacs becomes essentially
unusable.  Hence I propose the following patches to autorevert.el,
files.el and buff-menu.el, which are essentially just changes to my
own prior changes.  They would allow for a special return value `fast'
of buffer-stale-function, indicating that the function just returned
non-nil without really checking the need for reverting, because
reverting is fast anyway.  If there are no objections, I will install
these patches.

autorevert-diff2 assumes that autorevert-diff1 has been applied.  (See
the related thread autorevert and vc.)

===File ~/autorevert-diff2==================================
diff -c /home/teirllm/emacscvsdir/emacs/lisp/autorevert.el 
/home/teirllm/autorevert.latest.el
*** /home/teirllm/emacscvsdir/emacs/lisp/autorevert.el  Mon Mar 29 19:39:15 2004
--- /home/teirllm/autorevert.latest.el  Mon Mar 29 19:30:48 2004
***************
*** 293,309 ****
  This is an internal function used by Auto-Revert Mode."
    (unless (buffer-modified-p)
      (let (revert)
!       (when (or (and (buffer-file-name)
!                    (file-readable-p (buffer-file-name))
!                    (not (verify-visited-file-modtime (current-buffer))))
!               (and (or auto-revert-mode global-auto-revert-non-file-buffers)
!                    revert-buffer-function
!                    (boundp 'buffer-stale-function)
!                    (functionp buffer-stale-function)
!                    (funcall buffer-stale-function t)))
!       (setq revert t))
        (when revert
!       (when auto-revert-verbose
          (message "Reverting buffer `%s'." (buffer-name)))
        (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes))
        ;; `preserve-modes' avoids changing the (minor) modes.  But we
--- 293,310 ----
  This is an internal function used by Auto-Revert Mode."
    (unless (buffer-modified-p)
      (let (revert)
!       (or (and (buffer-file-name)
!              (file-readable-p (buffer-file-name))
!              (not (verify-visited-file-modtime (current-buffer)))
!              (setq revert t))
!         (and (or auto-revert-mode global-auto-revert-non-file-buffers)
!              revert-buffer-function
!              (boundp 'buffer-stale-function)
!              (functionp buffer-stale-function)
!              (setq revert (funcall buffer-stale-function t))))
        (when revert
!       (when (and auto-revert-verbose
!                  (not (eq revert 'fast)))
          (message "Reverting buffer `%s'." (buffer-name)))
        (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes))
        ;; `preserve-modes' avoids changing the (minor) modes.  But we

Diff finished.  Mon Mar 29 19:41:32 2004
============================================================

===File ~/files.el-diff=====================================
*** files.el    26 Mar 2004 21:55:58 -0600      1.686
--- files.el    29 Mar 2004 19:51:38 -0600      
***************
*** 3458,3465 ****
    "Function to check whether a non-file buffer needs reverting.
  This should be a function with one optional argument NOCONFIRM.
  Auto Revert Mode sets NOCONFIRM to t.  The function should return
! non-nil if the buffer should be reverted.  The buffer is current
! when this function is called.
  
  The idea behind the NOCONFIRM argument is that it should be
  non-nil if the buffer is going to be reverted without asking the
--- 3458,3467 ----
    "Function to check whether a non-file buffer needs reverting.
  This should be a function with one optional argument NOCONFIRM.
  Auto Revert Mode sets NOCONFIRM to t.  The function should return
! non-nil if the buffer should be reverted.  A return value of
! `fast' means that the need for reverting was not checked, but
! that reverting the buffer is fast.  The buffer is current when
! this function is called.
  
  The idea behind the NOCONFIRM argument is that it should be
  non-nil if the buffer is going to be reverted without asking the
============================================================

===File ~/buff-menu.el-diff=================================
*** buff-menu.el        26 Mar 2004 19:53:00 -0600      1.65
--- buff-menu.el        29 Mar 2004 19:48:59 -0600      
***************
*** 185,191 ****
    (set (make-local-variable 'revert-buffer-function)
         'Buffer-menu-revert-function)
    (set (make-local-variable 'buffer-stale-function)
!        #'(lambda (&optional noconfirm) t))
    (setq truncate-lines t)
    (setq buffer-read-only t)
    (run-hooks 'buffer-menu-mode-hook))
--- 185,191 ----
    (set (make-local-variable 'revert-buffer-function)
         'Buffer-menu-revert-function)
    (set (make-local-variable 'buffer-stale-function)
!        #'(lambda (&optional noconfirm) 'fast))
    (setq truncate-lines t)
    (setq buffer-read-only t)
    (run-hooks 'buffer-menu-mode-hook))
============================================================