[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: nesting of unwind-protect and atomic-change-group
From: |
Stefan Monnier |
Subject: |
Re: nesting of unwind-protect and atomic-change-group |
Date: |
Mon, 04 Feb 2008 10:21:38 -0500 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.0.50 (gnu/linux) |
> fun1 throws an error and puts point at the buffer location the error
> refers to. fun2 does not put point at the buffer location that
> corresponds to the error. The only difference between fun1 and fun2
> is the order of unwind-protect and atomic-change-group.
> (I find it counterintuitive that both functions put the message
> "search "foo"" in the *Messages* buffer before the error message,
> but I expect that this has to do with how the error is handled.)
When atomic-change-group undoes changes, it does it like "undo", which
means it also moves point. That's what you're seeing: the goto-char in
your unwind-protect is "ignored" because the subsequent undo moves
point elsewhere.
Maybe we should wrap cancel-change-group within save-excursion, as in
the patch below?
Stefan
--- orig/lisp/subr.el
+++ mod/lisp/subr.el
@@ -2008,6 +2008,7 @@
(defun cancel-change-group (handle)
"Finish a change group made with `prepare-change-group' (which see).
This finishes the change group by reverting all of its changes."
+ (save-excursion
(dolist (elt handle)
(with-current-buffer (car elt)
(setq elt (cdr elt))
@@ -2029,7 +2030,7 @@
(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)))))
+ (setq buffer-undo-list elt))))))
;;;; Display-related functions.
.