Subject: bug#810: 23.0.60; atomic-change-group narrowing problem

From: martin rudalics <[email-masked]>
Date: Mon, 01 Sep 2008 19:56:54 +0200

> When using atomic-change-group I got the message
 >
 >   undo-more: Changes to be undone are outside visible portion of buffer
 >
 > The changes are also not undone. This seems wrong to me.

The attached patch now also tries to restore any narrowing in force
before the atomic change.

martin
*** subr.el.~1.604.~	2008-08-31 09:48:50.531250000 +0200
--- subr.el	2008-09-01 19:52:32.843750000 +0200
***************
*** 1907,1912 ****
--- 1907,1917 ----
  
  ;;; Atomic change groups.
  
+ (defvar atomic-change-point-min nil
+   "Value returned by `point-min' before an atomic change.")
+ (defvar atomic-change-point-max nil
+   "Value returned by `point-max' before an atomic change.")
+ 
  (defmacro atomic-change-group (&rest body)
    "Perform BODY as an atomic change group.
  This means that if BODY exits abnormally,
***************
*** 1920,1925 ****
--- 1925,1932 ----
    (let ((handle (make-symbol "--change-group-handle--"))
  	(success (make-symbol "--change-group-success--")))
      `(let ((,handle (prepare-change-group))
+ 	   (atomic-change-point-min (point-min))
+ 	   (atomic-change-point-max (point-max))
  	   ;; Don't truncate any undo data in the middle of this.
  	   (undo-outer-limit nil)
  	   (undo-limit most-positive-fixnum)
***************
*** 1992,2017 ****
    (dolist (elt handle)
      (with-current-buffer (car elt)
        (setq elt (cdr elt))
!       (let ((old-car
!              (if (consp elt) (car elt)))
!             (old-cdr
!              (if (consp elt) (cdr elt))))
!         ;; Temporarily truncate the undo log at ELT.
!         (when (consp elt)
!           (setcar elt nil) (setcdr elt nil))
!         (unless (eq last-command 'undo) (undo-start))
!         ;; Make sure there's no confusion.
!         (when (and (consp elt) (not (eq elt (last pending-undo-list))))
!           (error "Undoing to some unrelated state"))
!         ;; Undo it all.
!         (save-excursion
!           (while (listp pending-undo-list) (undo-more 1)))
!         ;; Reset the modified cons cell ELT to its original content.
!         (when (consp elt)
!           (setcar elt old-car)
!           (setcdr elt old-cdr))
!         ;; Revert the undo info to what it was when we grabbed the state.
!         (setq buffer-undo-list elt)))))
  
  ;;;; Display-related functions.
  
--- 1999,2030 ----
    (dolist (elt handle)
      (with-current-buffer (car elt)
        (setq elt (cdr elt))
!       (save-restriction
! 	(widen)
! 	(let ((old-car
! 	       (if (consp elt) (car elt)))
! 	      (old-cdr
! 	       (if (consp elt) (cdr elt))))
! 	  ;; Temporarily truncate the undo log at ELT.
! 	  (when (consp elt)
! 	    (setcar elt nil) (setcdr elt nil))
! 	  (unless (eq last-command 'undo) (undo-start))
! 	  ;; Make sure there's no confusion.
! 	  (when (and (consp elt) (not (eq elt (last pending-undo-list))))
! 	    (error "Undoing to some unrelated state"))
! 	  ;; Undo it all.
! 	  (save-excursion
! 	    (while (listp pending-undo-list) (undo-more 1)))
! 	  ;; Reset the modified cons cell ELT to its original content.
! 	  (when (consp elt)
! 	    (setcar elt old-car)
! 	    (setcdr elt old-cdr))
! 	  ;; Revert the undo info to what it was when we grabbed the state.
! 	  (setq buffer-undo-list elt)))
!       (unless (and (= (point-min) atomic-change-point-min)
! 		   (= (point-max) atomic-change-point-max))
! 	;; Try to restore narrowing in force before atomic change.
! 	(narrow-to-region atomic-change-point-min atomic-change-point-max)))))
  
  ;;;; Display-related functions.