bug#58863: 29.0.50; Newly opened Dired buffers are usually modified

bug#58863: 29.0.50; Newly opened Dired buffers are usually modified

[daanturo]

When I open a new Dired buffer without doing anything,
`buffer-modified-p` usually returns `t`, especially for directories
under $HOME.

```bash

emacs -Q --eval "(progn
(find-file \"$(mktemp -d)\")
(print (buffer-modified-p (current-buffer))))"

```
Observed: Emacs prints `t`
Expected: Emacs prints `nil`

Instead of "$(mktemp -d)", "~" is also reproducible, but not "/".

This looks like a regression of current master that doesn't present on
Emacs 28.1.



In GNU Emacs 29.0.50 (build 1, x86_64-redhat-linux-gnu, GTK+ Version
3.24.34, cairo version 1.17.6) of 2022-09-20 built on
70af63ab8cb74358a721dd6e027251c6
System Description: Fedora Linux 36 (Container Image)

Configured using:
'configure --build=x86_64-redhat-linux-gnu
--host=x86_64-redhat-linux-gnu --program-prefix=
--disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
--bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
--datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
--libexecdir=/usr/libexec --localstatedir=/var
--sharedstatedir=/var/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
--with-rsvg --with-tiff --with-xft --with-xpm --with-gpm=no
--with-xwidgets --with-modules --with-harfbuzz --with-cairo --with-json
--with-pgtk --with-native-compilation --enable-link-time-optimization
build_alias=x86_64-redhat-linux-gnu host_alias=x86_64-redhat-linux-gnu
CC=gcc 'CFLAGS=-DMAIL_USE_LOCKF -O2 -flto=auto -ffat-lto-objects
-fexceptions -g -grecord-gcc-switches -pipe -Wall
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-Wp,-D_GLIBCXX_ASSERTIONS
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
LDFLAGS=-Wl,-z,relro
PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig CXX=g++
'CXXFLAGS=-O2 -flto=auto -ffat-lto-objects -fexceptions -g
-grecord-gcc-switches -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection''

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY
INOTIFY PDUMPER PGTK PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS XIM XWIDGETS GTK3 ZLIB

Important settings:
value of $LANG: C.UTF-8
value of $XMODIFIERS: @im=fcitx
locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
fido-vertical-mode: t
icomplete-vertical-mode: t
icomplete-mode: t
fido-mode: t
electric-pair-mode: t
tooltip-mode: t
global-eldoc-mode: t
eldoc-mode: t
show-paren-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
line-number-mode: t
indent-tabs-mode: t
transient-mark-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils comp comp-cstr
warnings icons subr-x rx cl-seq cl-macs gv cl-extra help-mode bytecomp
byte-compile cconv icomplete cl-loaddefs cl-lib cus-start cus-load
elec-pair rmc iso-transl tooltip eldoc paren electric uniquify
ediff-hook vc-hooks lisp-float-type elisp-mode mwheel term/pgtk-win
pgtk-win term/common-win pgtk-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list replace newcomment text-mode lisp-mode prog-mode
register page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
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 emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads
xwidget-internal dbusbind inotify dynamic-setting system-font-setting
font-render-setting cairo gtk pgtk lcms2 multi-tty make-network-process
native-compile emacs)

Memory information:
((conses 16 86590 8773)
(symbols 48 8185 0)
(strings 32 21527 2095)
(string-bytes 1 632357)
(vectors 16 15937)
(vector-slots 8 323876 11092)
(floats 8 40 480)
(intervals 56 423 0)
(buffers 1000 11))

-- 
Daanturo.

bug#58863: 29.0.50; Newly opened Dired buffers are usually modified

[Eli Zaretskii]

> Date: Sat, 29 Oct 2022 18:01:06 +0700
> From: daanturo <daanturo@gmail.com>
> 
> When I open a new Dired buffer without doing anything,
> `buffer-modified-p` usually returns `t`, especially for directories
> under $HOME.
> 
> ```bash
> 
> emacs -Q --eval "(progn
> (find-file \"$(mktemp -d)\")
> (print (buffer-modified-p (current-buffer))))"
> 
> ```
> Observed: Emacs prints `t`
> Expected: Emacs prints `nil`
> 
> Instead of "$(mktemp -d)", "~" is also reproducible, but not "/".
> 
> This looks like a regression of current master that doesn't present on
> Emacs 28.1.

Thanks, fixed.