bug#47497: 28.0.50; dired: does not distinguish between local directory and remote

bug#47497: 28.0.50; dired: does not distinguish between local directory and remote

[Jean Louis]

If there exists local directory: /scp:static: by using Dired and
pressing RET, Emacs will try to open connection over Tramp and show
remote files.

Is Tramp working on improbability that users will never have such
directories in / root file system?

Now I can guess that other similar root directories would also cause
Emacs to behave now how user thinks, as it relies on improbabilities and
not file verification.

  /:
  total used in directory 112K available 27.8 GiB
  lrwxrwxrwx   1    7 Feb  7 07:29 bin -> usr/bin
  drwxr-xr-x   3 4.0K Mar 15 11:40 boot
  drwxr-xr-x  20 3.9K Mar 29 14:56 dev
  drwxr-xr-x  82 4.0K Mar 29 18:15 etc
  drwxr-xr-x   7 4.0K Nov  5 13:50 home
  lrwxrwxrwx   1    7 Feb  7 07:29 lib -> usr/lib
  lrwxrwxrwx   1    7 Feb  7 07:29 lib64 -> usr/lib
  drwx------   2  16K Mar 15 10:48 lost+found
  drwxr-xr-x   9 4.0K Mar 28 13:06 mnt
  drwxr-xr-x   2 4.0K Sep 28  2020 opt
  drwxr-xr-x   5 4.0K Mar 18 10:19 package
  dr-xr-xr-x 245    0 Mar 29 08:18 proc
  drwxr-x---  13 4.0K Mar 30 13:39 root
  drwxr-xr-x  21  700 Mar 30 12:34 run
  lrwxrwxrwx   1    7 Feb  7 07:29 sbin -> usr/bin
  drwxr-xr-x   2 4.0K Mar 30 13:51 scp:static:
  drwxr-xr-x   4 4.0K Mar 15 11:12 srv
  dr-xr-xr-x  13    0 Mar 29 08:18 sys
  drwxrwxrwt   6  48K Mar 29 16:39 tmp
  drwxr-xr-x   9 4.0K Mar 18 10:21 usr
  drwxr-xr-x  13 4.0K Mar 28 11:18 var



In GNU Emacs 28.0.50 (build 2, x86_64-pc-linux-gnu, X toolkit, cairo version 1.17.4, Xaw scroll bars)
 of 2021-03-22 built on protected.rcdrun.com
Repository revision: cb5d1fe1aa9f280d60fcb33b58fc83ace3d95081
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12010000
Configured using:
 'configure --with-x-toolkit=lucid'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY
PDUMPER PNG RSVG SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM
LUCID ZLIB

Important settings:
  value of $LC_ALL: en_US.UTF-8
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: @im=exwm-xim
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-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
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail
rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json map text-property-search time-date
subr-x seq byte-opt gv bytecomp byte-compile cconv mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs
cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
iso-transl 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 easymenu timer select scroll-bar mouse jit-lock
font-lock syntax 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 x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 55095 8914)
 (symbols 48 7046 1)
 (strings 32 20619 1763)
 (string-bytes 1 649562)
 (vectors 16 13853)
 (vector-slots 8 181036 8554)
 (floats 8 23 46)
 (intervals 56 252 0)
 (buffers 992 12))

-- 
Thanks,
Jean Louis

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bug#47497: 28.0.50; dired: does not distinguish between local directory and remote

[Michael Albinus]

Jean Louis <bugs@gnu.support> writes:

Hi Jean,

> If there exists local directory: /scp:static: by using Dired and
> pressing RET, Emacs will try to open connection over Tramp and show
> remote files.
>
> Is Tramp working on improbability that users will never have such
> directories in / root file system?

Tramp handles this case, if instructed. Read the Tramp manual, chapter
"Frequesntly Asked Questions":

--8<---------------cut here---------------start------------->8---
        − To deactivate TRAMP for some look-alike remote file names,
          set ‘tramp-ignored-file-name-regexp’ to a proper regexp in
          ‘.emacs’.  *Note*, that we don’t use
          ‘customize-set-variable’, in order to avoid loading TRAMP.

               (setq tramp-ignored-file-name-regexp "\\`/ssh:example\\.com:")

          This is needed, if you mount for example a virtual file
          system on your local host’s root directory as
          ‘/ssh:example.com:’.
--8<---------------cut here---------------end--------------->8---

I'm closing the bug, because there's no error. The problem was discussed
in bug#31489 initially.

Best regards, Michael.