Package: emacs;
Reported by: Dave Abrahams <dave <at> boostpro.com>
Date: Sat, 28 Jul 2012 20:55:01 UTC
Severity: normal
Found in version 24.1
Done: martin rudalics <rudalics <at> gmx.at>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Alp Aker <alptekin.aker <at> gmail.com> To: martin rudalics <rudalics <at> gmx.at> Cc: Dave Abrahams <dave <at> boostpro.com>, 12081 <at> debbugs.gnu.org Subject: bug#12081: 24.1; buffer-predicate often not called Date: Sun, 29 Jul 2012 13:31:18 -0400
On Sun, Jul 29, 2012 at 1:08 PM, martin rudalics <rudalics <at> gmx.at> wrote:
> I see. But `kill-buffer' calls `replace-buffer-in-windows' which
> doesn't call `other-buffer'. Only if the buffer to be killed is still
> current after that, `kill-buffer' calls `other-buffer'. In the scenario
> above it is not called.
>
> Why is showing the buffer visiting /tmp/xx bad in your scenario? Can
> you give a scenario where the present behavior really hurts you? In
> that case we can try to ignore such a buffer in `switch-to-prev-buffer'.
Well, note that it's a regression: replace-buffer-in-windows used to
call other-window (via window-loop).
As for how it hurts not to check buffer predicates in
swtich-to-prev-buffer: Buffer predicates are supposed to provide a
way of exercising some control over what buffers are automatically
selected for display. But if kill-buffer doesn't respect buffer
predicates, then there's not much point to setting up a buffer
predicate at all: why bother filtering buffers chosen for display, if
the filter isn't respected by one of the most common ways in which a
buffer is chosen for the user?
It seems like something like the following would restore the old functionality:
=== modified file 'lisp/window.el'
--- lisp/window.el 2012-07-18 10:02:54 +0000
+++ lisp/window.el 2012-07-29 16:59:18 +0000
@@ -2679,10 +2679,12 @@
(old-buffer (window-buffer window))
;; Save this since it's destroyed by `set-window-buffer'.
(next-buffers (window-next-buffers window))
+ (pred (frame-parameter frame 'buffer-predicate))
entry new-buffer killed-buffers visible)
(when (window-dedicated-p window)
(error "Window %s is dedicated to buffer %s" window old-buffer))
+ (unless
(catch 'found
;; Scan WINDOW's previous buffers first, skipping entries of next
;; buffers.
@@ -2692,6 +2694,7 @@
(not (setq killed-buffers
(cons new-buffer killed-buffers))))
(not (eq new-buffer old-buffer))
+ (or (null pred) (funcall pred new-buffer))
(or bury-or-kill
(not (memq new-buffer next-buffers))))
(if (and (not switch-to-visible-buffer)
@@ -2713,6 +2716,7 @@
(when (and (buffer-live-p buffer)
(not (eq buffer old-buffer))
(not (eq (aref (buffer-name buffer) 0) ?\s))
+ (or (null pred) (funcall pred buffer))
(or bury-or-kill (not (memq buffer next-buffers))))
(if (get-buffer-window buffer frame)
;; Try to avoid showing a buffer visible in some other window.
@@ -2731,16 +2735,22 @@
(not (setq killed-buffers
(cons buffer killed-buffers))))
(not (eq buffer old-buffer))
+ (or (null pred) (funcall pred buffer))
(setq entry (assq buffer (window-prev-buffers window))))
(setq new-buffer buffer)
(set-window-buffer-start-and-point
window new-buffer (nth 1 entry) (nth 2 entry))
- (throw 'found t))))
-
- ;; Show a buffer visible in another window.
- (when visible
- (setq new-buffer visible)
- (set-window-buffer-start-and-point window new-buffer)))
+ (throw 'found t)))))
+
+ ;; If we reach this, then either: (1) we have a
+ ;; candidate buffer that was skipped because it was already visible on
+ ;; the frame, in which case we switch to it now, or (2) no candidate
+ ;; was found, in which case we switch to *scratch*.
+ (if visible
+ (setq new-buffer visible)
+ (setq new-buffer (get-buffer-create "*scratch*")))
+ (set-window-buffer-start-and-point window new-buffer))
+
(if bury-or-kill
;; Remove `old-buffer' from WINDOW's previous and (restored list
@@ -2773,10 +2783,12 @@
(frame (window-frame window))
(old-buffer (window-buffer window))
(next-buffers (window-next-buffers window))
+ (pred (frame-parameter frame 'buffer-predicate))
new-buffer entry killed-buffers visible)
(when (window-dedicated-p window)
(error "Window %s is dedicated to buffer %s" window old-buffer))
+ (unless
(catch 'found
;; Scan WINDOW's next buffers first.
(dolist (buffer next-buffers)
@@ -2784,6 +2796,7 @@
(not (setq killed-buffers
(cons buffer killed-buffers))))
(not (eq buffer old-buffer))
+ (or (null pred) (funcall pred buffer))
(setq entry (assq buffer (window-prev-buffers window))))
(setq new-buffer buffer)
(set-window-buffer-start-and-point
@@ -2794,6 +2807,7 @@
(dolist (buffer (buffer-list frame))
(when (and (buffer-live-p buffer) (not (eq buffer old-buffer))
(not (eq (aref (buffer-name buffer) 0) ?\s))
+ (or (null pred) (funcall pred buffer))
(not (assq buffer (window-prev-buffers window))))
(if (get-buffer-window buffer frame)
;; Try to avoid showing a buffer visible in some other window.
@@ -2808,6 +2822,7 @@
(or (buffer-live-p new-buffer)
(not (setq killed-buffers
(cons new-buffer killed-buffers))))
+ (or (null pred) (funcall pred new-buffer))
(not (eq new-buffer old-buffer)))
(if (and (not switch-to-visible-buffer)
(get-buffer-window new-buffer frame))
@@ -2816,12 +2831,17 @@
(setq visible new-buffer))
(set-window-buffer-start-and-point
window new-buffer (nth 1 entry) (nth 2 entry))
- (throw 'found t))))
-
- ;; Show a buffer visible in another window.
- (when visible
- (setq new-buffer visible)
- (set-window-buffer-start-and-point window new-buffer)))
+ (throw 'found t)))))
+
+ ;; If we reach this, then either: (1) we have a candidate buffer that
+ ;; was skipped because it was already visible on the frame, in which
+ ;; case we switch to it now, or (2) no candidate was found, in which
+ ;; case we switch to *scratch*.
+ (if visible
+ (setq new-buffer visible)
+ (setq new-buffer (get-buffer-create "*scratch*")))
+ (set-window-buffer-start-and-point window new-buffer))
+
;; Remove `new-buffer' from and restore WINDOW's next buffers.
(set-window-next-buffers window (delq new-buffer next-buffers))
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