bug#1655: 23.0.60; visiting tarball marks the buffer as modified

bug#1655: 23.0.60; visiting tarball marks the buffer as modified

[Sven Joachim]

Visiting a tar archive results in the buffer containing its contents
being marked as modified.


In GNU Emacs 23.0.60.2 (x86_64-unknown-linux-gnu, GTK+ Version 2.12.11)
 of 2008-12-21 on turtle
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: C
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Group

Minor modes in effect:
  gnus-undo-mode: t
  display-time-mode: t
  auto-image-file-mode: t
  show-paren-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  temp-buffer-resize-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x d / t m p <return> <down> <down> <down> <down> 
<return> <escape> ~ <f10> C-x k <return> g <up> <down> 
<return> <escape> ~ C-x k <return> M-x g n u s <return> 
M-x r e p o r t - e m <tab> <return>

Recent messages:
Reading active file from archive via nnfolder...
Opening nnfolder server on archive...done
Reading active file from archive via nnfolder...done
Opening nnfolder server...done
No new newsgroups
Checking new news...
Opening nnfolder server on archive...done
Opening nntp server on news.gnus.org...done
Opening nntp server on news.motzarella.org...done
Checking new news...done

bug#1655: 23.0.60; visiting tarball marks the buffer as modified

[Sven Joachim]

On 2008-12-21 10:13 +0100, Sven Joachim wrote:

> Visiting a tar archive results in the buffer containing its contents
> being marked as modified.

While this showed up fairly recently, the problem probably has existed
for much longer, but had been hidden by bug #1509 (epa-find-file-hook
marking the buffer as unmodified).

Will investigate this issue further if time permits.

Sven

bug#1655: 23.0.60; visiting tarball marks the buffer as modified

[Sven Joachim]

tags 1655 + patch
thanks

On 2008-12-23 12:44 +0100, Sven Joachim wrote:

> On 2008-12-21 10:13 +0100, Sven Joachim wrote:
>
>> Visiting a tar archive results in the buffer containing its contents
>> being marked as modified.
>
> While this showed up fairly recently, the problem probably has existed
> for much longer, but had been hidden by bug #1509 (epa-find-file-hook
> marking the buffer as unmodified).
>
> Will investigate this issue further if time permits.

Found out that the problem is in the buffer-swap-text calls in tar-mode
and tar-change-major-mode-hook that change the buffer.  The following
patch works for me:

2008-12-23  Sven Joachim  <svenjoac@gmx.de>

	* tar-mode.el (tar-mode, tar-change-major-mode-hook): Avoid
	marking buffer as modified.

--8<---------------cut here---------------start------------->8---
--- tar-mode.el.~1.130.~	2008-06-01 10:42:56.000000000 +0200
+++ tar-mode.el	2008-12-23 17:11:12.000000000 +0100
@@ -577,8 +577,10 @@
 (put 'tar-subfile-mode 'mode-class 'special)
 
 (defun tar-change-major-mode-hook ()
-  ;; Bring the actual Tar data back into the main buffer.
-  (when (tar-data-swapped-p) (buffer-swap-text tar-data-buffer))
+  (let ((modified-p (buffer-modified-p)))
+    ;; Bring the actual Tar data back into the main buffer.
+    (when (tar-data-swapped-p) (buffer-swap-text tar-data-buffer))
+    (restore-buffer-modified-p modified-p))
   ;; Throw away the summary.
   (when (buffer-live-p tar-data-buffer) (kill-buffer tar-data-buffer)))
 
@@ -630,8 +632,10 @@
        (generate-new-buffer (format " *tar-data %s*"
                                     (file-name-nondirectory
                                      (or buffer-file-name (buffer-name))))))
-  (buffer-swap-text tar-data-buffer)
-  (tar-summarize-buffer)
+  (let ((modified-p (buffer-modified-p)))
+    (buffer-swap-text tar-data-buffer)
+    (tar-summarize-buffer)
+    (restore-buffer-modified-p modified-p))
   (tar-next-line 0))
--8<---------------cut here---------------end--------------->8---

Processed: Re: bug#1655: 23.0.60; visiting tarball marks the buffer as modified

[Emacs bug Tracking System]

Processing commands for control@emacsbugs.donarmstrong.com:

> tags 1655 + patch
bug#1655: 23.0.60; visiting tarball marks the buffer as modified
There were no tags set.
Tags added: patch

> thanks
Stopping processing here.

Please contact me if you need assistance.

Don Armstrong
(administrator, Emacs bugs database)

bug#1655: marked as done (23.0.60; visiting tarball marks the buffer as modified)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 864 bytes --]


Your message dated Fri, 26 Dec 2008 21:36:40 +0100
with message-id <878wq2n06f.fsf@turtle.gmx.de>
and subject line fixed in tar-mode.el 1.131
has caused the Emacs bug report #1655,
regarding 23.0.60; visiting tarball marks the buffer as modified
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@emacsbugs.donarmstrong.com
immediately.)


-- 
1655: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=1655
Emacs Bug Tracking System
Contact owner@emacsbugs.donarmstrong.com with problems

[-- Attachment #2: Type: message/rfc822, Size: 3875 bytes --]

From: Sven Joachim <svenjoac@gmx.de>
To: emacs-pretest-bug@gnu.org
Subject: 23.0.60; visiting tarball marks the buffer as modified
Date: Sun, 21 Dec 2008 10:13:16 +0100
Message-ID: <87r641x55f.fsf@turtle.gmx.de>


Visiting a tar archive results in the buffer containing its contents
being marked as modified.


In GNU Emacs 23.0.60.2 (x86_64-unknown-linux-gnu, GTK+ Version 2.12.11)
 of 2008-12-21 on turtle
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: C
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Group

Minor modes in effect:
  gnus-undo-mode: t
  display-time-mode: t
  auto-image-file-mode: t
  show-paren-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  temp-buffer-resize-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x d / t m p <return> <down> <down> <down> <down> 
<return> <escape> ~ <f10> C-x k <return> g <up> <down> 
<return> <escape> ~ C-x k <return> M-x g n u s <return> 
M-x r e p o r t - e m <tab> <return>

Recent messages:
Reading active file from archive via nnfolder...
Opening nnfolder server on archive...done
Reading active file from archive via nnfolder...done
Opening nnfolder server...done
No new newsgroups
Checking new news...
Opening nnfolder server on archive...done
Opening nntp server on news.gnus.org...done
Opening nntp server on news.motzarella.org...done
Checking new news...done



[-- Attachment #3: Type: message/rfc822, Size: 1467 bytes --]

From: Sven Joachim <svenjoac@gmx.de>
To: 1655-done@emacsbugs.donarmstrong.com
Subject: fixed in tar-mode.el 1.131
Date: Fri, 26 Dec 2008 21:36:40 +0100
Message-ID: <878wq2n06f.fsf@turtle.gmx.de>

Andreas Schwab's recent changes to tar-mode.el fixed this issue.