bug#45941: 28.0.50; rmail doesn't set modified flag when changing 'unseen' flag

bug#45941: 28.0.50; rmail doesn't set modified flag when changing 'unseen' flag

[Andrea G. Monaco]

Hello,


when I read a message for the first time in rmail, the unseen flag gets
cleared, but this does not set the modified flag of the buffer:
therefore the buffer can't be saved, nor Emacs offers to save it when I
close the program, and information about read messages gets usually
lost.

These are the relevant lines in rmail.el, inside rmail-show-message-1:

  ;; Mark the message as seen, but preserve buffer modified flag.
  (let ((modiff (buffer-modified-p)))
    (rmail-set-attribute rmail-unseen-attr-index nil)
    (unless modiff
      (restore-buffer-modified-p modiff)))


I'd prefer no special treatment of 'unseen' flag modification, so that
it set the modified flag.

I think that some users might prefer the current behavior, so we could
add a variable, maybe named rmail-unseen-change-set-modified, to
customize this.


Warmly,
Andrea Monaco



In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.5, cairo version 1.16.0)
 of 2020-12-01 built on agm
Repository revision: 90a543e630012cc58c175d5bf3ffd42bb156c6b6
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description: Debian GNU/Linux 10 (buster)

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY
INOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON
PDUMPER LCMS2

Important settings:
  value of $LC_MONETARY: it_IT.UTF-8
  value of $LC_NUMERIC: it_IT.UTF-8
  value of $LC_TIME: it_IT.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: RMAIL Summary

Minor modes in effect:
  display-time-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug sendmail shr-color color eieio-opt
cl-extra speedbar ezimage dframe find-func shortdoc help-fns radix-tree
help-mode misearch multi-isearch rmailsum shr kinsoku svg xml dom
browse-url url url-proxy url-privacy url-expand url-methods url-history
url-cookie url-domsuf url-util url-parse url-vars mailcap qp rmailmm
message rmc puny dired dired-loaddefs rfc822 mml easymenu mml-sec epa
derived epg epg-config gnus-util text-property-search time-date
mm-decode mm-bodies mm-encode mailabbrev gmm-utils mailheader mail-parse
rfc2231 rmail rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs cl-loaddefs cl-lib password-cache json subr-x map seq
byte-opt gv bytecomp byte-compile cconv rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils time tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese composite charscript charprop case-table epa-hook
jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button
loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote threads dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 191396 51037)
 (symbols 48 8932 2)
 (strings 32 128911 15394)
 (string-bytes 1 12255982)
 (vectors 16 118062)
 (vector-slots 8 1212654 84005)
 (floats 8 190 282)
 (intervals 56 5799 1278)
 (buffers 984 16))

bug#45941: [PATCH] add option to mark buffer as modified after reading new message

[Andrea G. Monaco]

Hello,


this patch from current rmail.el adds an option for marking buffer as
modified when a message is read for the first time. The variable defaults
to nil, so it should not change current behavior.


diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 29460cc20f..d800dce671 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -686,6 +686,10 @@ rmail-show-mime-function
 This function is called when `rmail-enable-mime' is non-nil.
 The package providing MIME support should set this.")
 
+(defvar rmail-read-new-message-trigger-modified nil
+  "If true, reading a message for the first time and thus clearing
+its unseen attribute triggers the modified flag for the RMAIL buffer.")
+
 ;;;###autoload
 (defvar rmail-insert-mime-forwarded-message-function nil
   "Function to insert a message in MIME format so it can be forwarded.
@@ -2747,10 +2751,11 @@ rmail-show-message-1
            (t (setq rmail-current-message msg)))
       (with-current-buffer rmail-buffer
        (setq header-style rmail-header-style)
-       ;; Mark the message as seen, but preserve buffer modified flag.
-       (let ((modiff (buffer-modified-p)))
+        ;; Mark the message as seen, but preserve buffer modified flag,
+       ;; unless rmail-read-new-message-trigger-modified is t
+        (let ((modiff (buffer-modified-p)))
          (rmail-set-attribute rmail-unseen-attr-index nil)
-         (unless modiff
+         (unless rmail-read-new-message-trigger-modified
            (restore-buffer-modified-p modiff)))
        ;; bracket the message in the mail
        ;; buffer and determine the coding system the transfer encoding.



-- 
Andrea G. Monaco
Hacker, mathematician, lgbt+ activist
"Hope will never be silent!", H. Milk

bug#45941: [PATCH] add option to mark buffer as modified after reading new message

[Andreas Schwab]

On Jan 27 2021, Andrea G. Monaco wrote:

> diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
> index 29460cc20f..d800dce671 100644
> --- a/lisp/mail/rmail.el
> +++ b/lisp/mail/rmail.el
> @@ -686,6 +686,10 @@ rmail-show-mime-function
>  This function is called when `rmail-enable-mime' is non-nil.
>  The package providing MIME support should set this.")
>  
> +(defvar rmail-read-new-message-trigger-modified nil
> +  "If true, reading a message for the first time and thus clearing

The first line of the docstring should be a complete sentence.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#45941: [PATCH] add option to mark buffer as modified after reading new message

[Andrea G. Monaco]

  > The first line of the docstring should be a complete sentence.
  > Andreas.

Thanks, I didn't know that. I fixed it and also chose a more fitting
name for the variable.


diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 29460cc20f..749cdd5891 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -686,6 +686,9 @@ rmail-show-mime-function
 This function is called when `rmail-enable-mime' is non-nil.
 The package providing MIME support should set this.")
 
+(defvar rmail-showing-new-message-sets-modified nil
+  "If non-nil, showing a new message sets the modified flag for the RMAIL buffer.")
+
 ;;;###autoload
 (defvar rmail-insert-mime-forwarded-message-function nil
   "Function to insert a message in MIME format so it can be forwarded.
@@ -2747,10 +2750,11 @@ rmail-show-message-1
            (t (setq rmail-current-message msg)))
       (with-current-buffer rmail-buffer
        (setq header-style rmail-header-style)
-       ;; Mark the message as seen, but preserve buffer modified flag.
-       (let ((modiff (buffer-modified-p)))
+        ;; Mark the message as seen, but preserve buffer modified flag,
+       ;; unless rmail-showing-new-message-sets-modified is non-nil
+        (let ((modiff (buffer-modified-p)))
          (rmail-set-attribute rmail-unseen-attr-index nil)
-         (unless modiff
+         (unless rmail-showing-new-message-sets-modified
            (restore-buffer-modified-p modiff)))
        ;; bracket the message in the mail
        ;; buffer and determine the coding system the transfer encoding.


-- 
Andrea G. Monaco
Hacker, mathematician, lgbt+ activist
"Hope will never be silent!", H. Milk

bug#45941: [PATCH] add option to mark buffer as modified after reading new message

[Eli Zaretskii]

> From: "Andrea G. Monaco" <andrea.monaco@autistici.org>
> Date: Wed, 27 Jan 2021 18:47:06 +0100
> 
> 
>   > The first line of the docstring should be a complete sentence.
>   > Andreas.
> 
> Thanks, I didn't know that. I fixed it and also chose a more fitting
> name for the variable.

Thanks, I installed this with some changes: the variable is now a user
option customizable via Custom, and I also added a NE|W|S entry about
it.

With that, I close the bug report.  Thank you for your contribution to
Emacs.