Subject: bug#13197: 24.3.50; org-odt.el code that kills modified buffers

From: "Drew Adams" <[email-masked]>
Date: Sat, 15 Dec 2012 14:35:45 -0800

This is a question, but it might also be a bug report regarding the code
cited.
 
IIUC, `set-buffer-modified-p' (and also `restore-buffer-modified-p',
which is a lousy name BTW) always acts on the current buffer.  There is
no way to tell it which buffer to act on, other than, say, using
`with-current-buffer'.
 
I use `find-file-noselect' over a large set of files, and at a later
point I kill many such visited-file buffers.  But even just
`find-file-no-select' can cause visiting to modify some buffers.  So
when I go to kill them I need to prevent the user being queried about
killing a modified buffer.
 
I was grepping some source files to see how other code handles this kind
of thing, and I came across this in org-odt.el (in
`org-odt-cleanup-xml-buffers'):
 
(mapc (lambda (file)
        (let ((buf (find-file-noselect
                     (expand-file-name file org-odt-zip-dir) t)))
          (when (buffer-name buf)
            (set-buffer-modified-p nil)
            (kill-buffer buf))))
      xml-files)
 
I don't see how that can work properly, since `find-file-noselect' does
not make the visited-file buffer current, and `set-buffer-modified-p'
acts only on the current buffer.
 
Am I missing something here, or is that a bug?
 
In any case, I would like to learn more about this.  Currently I am
doing this (since this code is for Emacs 23+, which has
`restore-buffer-modified-p'):
 
(with-current-buffer buf
  (restore-buffer-modified-p nil)
  (kill-buffer buf))
 
Is there a way to accomplish that without making BUF current?

In GNU Emacs 24.3.50.1 (i386-mingw-nt5.1.2600)
 of 2012-12-13 on ODIEONE
Bzr revision: 111211 [email-masked]
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.7) --no-opt --enable-checking --cflags
 -IC:/Devel/emacs/build/include -Wall -Wextra -Wno-sign-compare
 -Wno-type-limits -Wno-missing-field-initializers -Wno-pointer-sign
 -Wdeclaration-after-statement --ldflags -LC:/Devel/emacs/build/lib'