Package: emacs;
Reported by: Tino Calancha <tino.calancha <at> gmail.com>
Date: Sat, 5 Aug 2017 13:02:02 UTC
Severity: normal
Tags: patch
Found in version 26.0.50
Done: Tino Calancha <tino.calancha <at> gmail.com>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Tino Calancha <tino.calancha <at> gmail.com> To: 27968 <at> debbugs.gnu.org Cc: stephen berman <stephen.berman <at> gmx.net> Subject: bug#27968: 26.0.50; dired-revert: Saved positions might change if a dired header changes Date: Sat, 05 Aug 2017 22:01:34 +0900
X-Debbugs-CC: Stephen Berman <stephen.berman <at> gmx.net>
Tag: patch
Dired headers also changes; if you add/deleted some files,
the used space shown changes: that will mess up the saved
buffer positions if the length of the header is different.
This problem causes dired-test-bug27243-01 to fail in hydra.
One possible solution is the patch below. It saves line numbers
instead of positions. Line numbers won't change if a dired header
changes its length.
--8<-----------------------------cut here---------------start------------->8---
commit a6799f27a9d18618f3046a1db7ffebc480310e8f
Author: Tino Calancha <tino.calancha <at> gmail.com>
Date: Sat Aug 5 21:59:06 2017 +0900
dired-revert: save line numbers instead of positions
Positions might change if the length of one dired header line
changes; this happen, for instance, if we add new files.
https://lists.gnu.org/archive/html/emacs-devel/2017-07/msg01092.html
* lisp/dired.el (dired-save-positions): Save the line numbers at point.
(dired-restore-positions): Use forward-line to restore the original
position (Bug#27968).
* test/lisp/dired-tests.el (dired-test-bug27968): Add test.
diff --git a/lisp/dired.el b/lisp/dired.el
index 24759c6c9b..d04bd6fe03 100644
--- a/lisp/dired.el
+++ b/lisp/dired.el
@@ -1444,18 +1444,22 @@ dired-save-positions
The positions have the form (BUFFER-POSITION WINDOW-POSITIONS).
BUFFER-POSITION is the point position in the current Dired buffer.
-It has the form (BUFFER DIRED-FILENAME BUFFER-POINT).
+It has the form (BUFFER DIRED-FILENAME BUFFER-LINE-NUMBER).
WINDOW-POSITIONS are current positions in all windows displaying
this dired buffer. The window positions have the form (WINDOW
-DIRED-FILENAME WINDOW-POINT)."
+DIRED-FILENAME WINDOW-LINE-NUMBER).
+
+We store line numbers instead of point positions because the header
+lines might change as well: when this happen the line number doesn't
+change; the point does."
(list
- (list (current-buffer) (dired-get-filename nil t) (point))
+ (list (current-buffer) (dired-get-filename nil t) (line-number-at-pos))
(mapcar (lambda (w)
- (list w
- (with-selected-window w
- (dired-get-filename nil t))
- (window-point w)))
+ (with-selected-window w
+ (list w
+ (dired-get-filename nil t)
+ (line-number-at-pos (window-point w)))))
(get-buffer-window-list nil 0 t))))
(defun dired-restore-positions (positions)
@@ -1464,7 +1468,8 @@ dired-restore-positions
(buffer (nth 0 buf-file-pos)))
(unless (and (nth 1 buf-file-pos)
(dired-goto-file (nth 1 buf-file-pos)))
- (goto-char (nth 2 buf-file-pos))
+ (goto-char (point-min))
+ (forward-line (1- (nth 2 buf-file-pos)))
(dired-move-to-filename))
(dolist (win-file-pos (nth 1 positions))
;; Ensure that window still displays the original buffer.
@@ -1472,7 +1477,8 @@ dired-restore-positions
(with-selected-window (nth 0 win-file-pos)
(unless (and (nth 1 win-file-pos)
(dired-goto-file (nth 1 win-file-pos)))
- (goto-char (nth 2 win-file-pos))
+ (goto-char (point-min))
+ (forward-line (1- (nth 2 win-file-pos)))
(dired-move-to-filename)))))))
(defun dired-remember-marks (beg end)
diff --git a/test/lisp/dired-tests.el b/test/lisp/dired-tests.el
index b14bbc6360..4bbf72ab74 100644
--- a/test/lisp/dired-tests.el
+++ b/test/lisp/dired-tests.el
@@ -308,5 +308,44 @@ dired-dwim-target
(should (eq 2 (current-column))))
(dired-hide-details-mode orig))))
+(ert-deftest dired-test-bug27968 ()
+ (let* ((top-dir (make-temp-file "top-dir" t))
+ (subdir (expand-file-name "subdir" top-dir))
+ (header-len-fn (lambda ()
+ (save-excursion
+ (goto-char 1)
+ (forward-line 1)
+ (- (point-at-eol) (point)))))
+ orig-len len diff pos)
+ (make-directory subdir 'parents)
+ (unwind-protect
+ (with-current-buffer (dired-noselect subdir)
+ (setq orig-len (funcall header-len-fn)
+ pos (point))
+ ;; Bug arises when the header line changes its length; this may
+ ;; happen if the used space has changed: for instance, with the
+ ;; creation of additional files.
+ (make-directory "subdir" t)
+ (dired-revert)
+ ;; Change the header line.
+ (save-excursion
+ (goto-char 1)
+ (forward-line 1)
+ (let ((inhibit-read-only t))
+ (delete-region (point) (point-at-eol))
+ (insert " test-bug27968")))
+ (setq len (funcall header-len-fn)
+ diff (- len orig-len))
+ (should-not (zerop diff)) ; Header length has changed.
+ ;; If diff > 0, then the point moves back.
+ ;; If diff < 0, then the point moves forward.
+ ;; If diff = 0, then the point doesn't move.
+ ;; We correct `point' with diff to obtain the right line number.
+ (should (equal (line-number-at-pos (+ (point) diff))
+ (line-number-at-pos pos)))
+ ;; After revert, the point must be in 'subdir' line.
+ (should (equal "subdir" (dired-get-filename nil t))))
+ (delete-directory top-dir t))))
+
(provide 'dired-tests)
;; dired-tests.el ends here
--8<-----------------------------cut here---------------end--------------->8---
In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
of 2017-08-05 built on calancha-pc
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