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* lisp/subr.el (cancel-change-group): Reset cell in case of error

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Since the setcdr/setcdr is supposed to be temporary, use unwind-protect
to make sure we properly undo the temporary change even in case of error.
This commit is contained in:
Stefan Monnier 2016-07-26 13:14:50 -04:00
parent c54238db6a
commit 682fdae7ef
1 changed files with 21 additions and 20 deletions
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41
lisp/subr.el
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@ -2535,26 +2535,27 @@ This finishes the change group by reverting all of its changes."
;; Widen buffer temporarily so if the buffer was narrowed within
;; the body of `atomic-change-group' all changes can be undone.
(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))))))
(let ((old-car (car-safe elt))
(old-cdr (cdr-safe elt)))
(unwind-protect
(progn
;; 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)))
;; Revert the undo info to what it was when we grabbed
;; the state.
(setq buffer-undo-list elt))
;; Reset the modified cons cell ELT to its original content.
(when (consp elt)
(setcar elt old-car)
(setcdr elt old-cdr))))))))
;;;; Display-related functions.