* lisp/follow.el: Rework, eliminating reliance on advice.

(set-process-filter, process-filter, sit-for): Advice deleted.
(follow-mode-off-hook): Obsolete hook removed.
(follow-avoid-tail-recenter-p, follow-process-filter-alist): Vars
deleted.
(follow-auto): Use a :set function.
(follow-mode): Rewritten.  Don't advise process filters.
(follow-switch-to-current-buffer-all, follow-scroll-up)
(follow-scroll-down): Assume follow-mode is bound.
(follow-comint-scroll-to-bottom)
(follow-align-compilation-windows): New functions.
(follow--window-sorter): New function.
(follow-all-followers): Use it to explicitly sort windows by their
positions; don't make assumptions about next-window order.
(follow-windows-start-end, follow-delete-other-windows-and-split)
(follow-calc-win-start): Doc fix.
(follow-windows-aligned-p, follow-select-if-visible): Don't call
vertical-motion unnecessarily.
(follow-adjust-window): New function.
(follow-post-command-hook): Use it.
(follow-call-set-process-filter, follow-call-process-filter)
(follow-intercept-process-output, follow-tidy-process-filter-alist)
(follow-stop-intercept-process-output, follow-generic-filter):
Functions deleted.
(follow-scroll-bar-toolkit-scroll, follow-scroll-bar-drag)
(follow-scroll-bar-scroll-up, follow-scroll-bar-scroll-down): New
functions, replacing advice on scroll-bar-* commands.

* lisp/comint.el (comint-adjust-point): New function.
(comint-postoutput-scroll-to-bottom): Use it.  Call
follow-comint-scroll-to-bottom for Follow mode buffers.

etc/NEWS

@@ -100,6 +100,13 @@ these commands now).
 ** erc will look up server/channel names via auth-source and use the
 channel keys found, if any.
 
+** Follow mode
+
+*** The obsolete variable `follow-mode-off-hook' has been removed.
+
+*** Follow mode no longer works by using advice.
+The option `follow-intercept-processes' has been removed.
+
 ** The `server-auth-key' variable can be used to set a permanent
 shared key for Emacs Server.
 

lisp/ChangeLog

+2012-05-01  Chong Yidong  <cyd@gnu.org>
+
+	* follow.el: Eliminate advice.
+	(set-process-filter, process-filter, sit-for): Advice deleted.
+	(follow-mode-off-hook): Obsolete hook removed.
+	(follow-avoid-tail-recenter-p, follow-process-filter-alist): Vars
+	deleted.
+	(follow-auto): Use a :set function.
+	(follow-mode): Rewritten.  Don't advise process filters.
+	(follow-switch-to-current-buffer-all, follow-scroll-up)
+	(follow-scroll-down): Assume follow-mode is bound.
+	(follow-comint-scroll-to-bottom)
+	(follow-align-compilation-windows): New functions.
+	(follow--window-sorter): New function.
+	(follow-all-followers): Use it to explicitly sort windows by their
+	positions; don't make assumptions about next-window order.
+	(follow-windows-start-end, follow-delete-other-windows-and-split)
+	(follow-calc-win-start): Doc fix.
+	(follow-windows-aligned-p, follow-select-if-visible): Don't call
+	vertical-motion unnecessarily.
+	(follow-adjust-window): New function.
+	(follow-post-command-hook): Use it.
+	(follow-call-set-process-filter, follow-call-process-filter)
+	(follow-intercept-process-output, follow-tidy-process-filter-alist)
+	(follow-stop-intercept-process-output, follow-generic-filter):
+	Functions deleted.
+	(follow-scroll-bar-toolkit-scroll, follow-scroll-bar-drag)
+	(follow-scroll-bar-scroll-up, follow-scroll-bar-scroll-down): New
+	functions, replacing advice on scroll-bar-* commands.
+
+	* comint.el (comint-adjust-point): New function.
+	(comint-postoutput-scroll-to-bottom): Use it.  Call
+	follow-comint-scroll-to-bottom for Follow mode buffers.
+
 2012-05-01  Glenn Morris  <rgm@gnu.org>
 
 	* term/AT386.el, term/apollo.el, term/bobcat.el, term/cygwin.el:

lisp/comint.el

@@ -2101,43 +2101,51 @@ This function should be a pre-command hook."
                        (select-window selected))))
 	       nil t))))))
 
+(defvar follow-mode)
+(declare-function follow-comint-scroll-to-bottom "follow" ())
+
 (defun comint-postoutput-scroll-to-bottom (_string)
   "Go to the end of buffer in some or all windows showing it.
-Does not scroll if the current line is the last line in the buffer.
+Do not scroll if the current line is the last line in the buffer.
 Depends on the value of `comint-move-point-for-output' and
 `comint-scroll-show-maximum-output'.
 
 This function should be in the list `comint-output-filter-functions'."
-  (let* ((selected (selected-window))
-	 (current (current-buffer))
-	 (process (get-buffer-process current))
-	 (scroll comint-move-point-for-output))
+  (let* ((current (current-buffer))
+	 (process (get-buffer-process current)))
     (unwind-protect
-	(if process
-	    (walk-windows
-             (lambda (window)
-               (when (eq (window-buffer window) current)
-                 (select-window window)
-                 (if (and (< (point) (process-mark process))
-                          (or (eq scroll t) (eq scroll 'all)
-                              ;; Maybe user wants point to jump to end.
-                              (and (eq scroll 'this) (eq selected window))
-                              (and (eq scroll 'others) (not (eq selected window)))
-                              ;; If point was at the end, keep it at end.
-                              (and (marker-position comint-last-output-start)
-                                   (>= (point) comint-last-output-start))))
-                     (goto-char (process-mark process)))
-                 ;; Optionally scroll so that the text
-                 ;; ends at the bottom of the window.
-                 (if (and comint-scroll-show-maximum-output
-                          (= (point) (point-max)))
-                     (save-excursion
-                       (goto-char (point-max))
-                       (recenter (- -1 scroll-margin))))
-                 (select-window selected)))
-	     nil t))
+	(cond
+	 ((null process))
+	 ((bound-and-true-p follow-mode)
+	  (follow-comint-scroll-to-bottom))
+	 (t
+	  (let ((selected (selected-window)))
+	    (dolist (w (get-buffer-window-list current nil t))
+	      (select-window w)
+	      (unwind-protect
+		  (progn
+		    (comint-adjust-point selected)
+		    ;; Optionally scroll to the bottom of the window.
+		    (and comint-scroll-show-maximum-output
+			 (eobp)
+			 (recenter (- -1 scroll-margin))))
+		(select-window selected))))))
       (set-buffer current))))
 
+(defun comint-adjust-point (selected)
+  "Move point in the selected window based on Comint settings.
+SELECTED is the window that was originally selected."
+  (let ((process (get-buffer-process (current-buffer))))
+    (and (< (point) (process-mark process))
+	 (or (memq comint-move-point-for-output '(t all))
+	     ;; Maybe user wants point to jump to end.
+	     (eq comint-move-point-for-output
+		 (if (eq (selected-window) selected) 'this 'others))
+	     ;; If point was at the end, keep it at end.
+	     (and (marker-position comint-last-output-start)
+		  (>= (point) comint-last-output-start)))
+	 (goto-char (process-mark process)))))
+
 (defun comint-truncate-buffer (&optional _string)
   "Truncate the buffer to `comint-buffer-maximum-size'.
 This function could be on `comint-output-filter-functions' or bound to a key."