bug#75004: 30.0.92; documentation unclear about D-Bus support

bug#75004: 30.0.92; documentation unclear about D-Bus support

[Mike Kupfer]

I would like to use TRAMP to access the files on my Android phone.  It's
not working.  While trying to troubleshoot, I am finding the
documentation less than clear in a couple places, so I'm reporting those
shortcomings here.

1. The TRAMP "GVFS-based external methods" page says

  Emacs must have the message bus system, D-Bus integration active, see
  D-Bus(dbus).

I do not understand what it means for D-Bus integration to be "active".
Is it a runtime thing, or is it just talking about whether the code is
compiled in?  Is there a command to run, a variable to look at, or an
sexp to evaluate that would tell me whether D-Bus integration is
"active"?  I looked in the D-Bus Info documentation and wasn't able to
find any clues there.  Nor did a web search help.

2. The "D-Bus integration in Emacs" Info file just covers the API.  But
it assumes that you have D-Bus support compiled in.  I think there
should be some mention that D-Bus support is a compile-time option.  I
also would like to see instructions for how to tell if the necessary
code was, in fact, compiled in.  (The *Gnus* documentation says it's
(featurep 'dbusbind).  That's not the place users will look.)

In GNU Emacs 30.0.92 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.16.0, Xaw scroll bars) of 2024-10-28 built on alto
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
System Description: Debian GNU/Linux 12 (bookworm)

Configured using:
 'configure --prefix=/usr/local --with-native-compilation=no'

Configured features:
CAIRO FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG LIBSELINUX
LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG SECCOMP SOUND THREADS TIFF
TOOLKIT_SCROLL_BARS WEBP X11 XDBE XIM XPM LUCID ZLIB

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

Major mode: Info

Minor modes in effect:
  server-mode: t
  delete-selection-mode: t
  display-time-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  isearch-fold-quotes-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  minibuffer-regexp-mode: t
  buffer-read-only: 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 mh-identity emacsbug bug-reference texinfo texinfo-loaddefs
tabify man info apropos sort gnus-async gnus-bcklg gnus-kill gnus-ml
disp-table timezone network-stream url-http url-gw nsm url-cache
url-auth url-handlers nnrss nndoc nndraft nnnil gnus-agent gnus-srvr
nnvirtual nntp gnus-cache pcmpl-unix cl-print tramp-androidsu tramp-adb
tramp-archive tramp-cmds tramp-container tramp-ftp help-fns radix-tree
tramp-gvfs tramp-cache time-stamp tramp-sh tramp trampver
tramp-integration tramp-message tramp-compat tramp-loaddefs view crm
mh-alias org-clock grep compile vc-hg diff-mode track-changes easy-mmode
cal-move diary-lib diary-loaddefs cal-iso misearch multi-isearch
oc-basic ol-eww eww url-queue mm-url ol-rmail ol-mhe ol-irc ol-info
ol-gnus nnselect ol-docview doc-view filenotify jka-compr image-mode
exif ol-bibtex bibtex ol-bbdb ol-w3m ol-doi org-link-doi cl-extra
help-mode face-remap org-agenda org-element org-persist xdg org-id
org-element-ast inline avl-tree generator org-refile org ob ob-tangle
ob-ref ob-lob ob-table ob-exp org-macro org-src sh-script smie treesit
executable ob-comint org-pcomplete org-list org-footnote org-faces
org-entities org-version ob-emacs-lisp ob-core ob-eval org-cycle
org-table ol rx org-fold org-fold-core org-keys oc org-loaddefs
find-func cal-menu calendar cal-loaddefs org-compat org-macs format-spec
dired-aux dired-x textsec uni-scripts idna-mapping ucs-normalize
uni-confusable textsec-check shr-color color qp mail-extr smiley
mm-archive pp mh-search mh-letter mh-show goto-addr thingatpt gnus-cite
mh-mime mule-util mh-thread mh-inc hl-line mh-tool-bar mh-acros mh-seq
mh-xface mh-utils mh-folder which-func imenu files-x mdk-mail gnus-mh
gnus-msg mh-comp mh-scan mh-gnus gnus-dup nnmh gnus-score score-mode
gnus-art mm-uu mml2015 mm-view mml-smime smime gnutls dig gnus-sum shr
pixel-fill kinsoku url-file svg dom gnus-group gnus-undo gnus-start
gnus-dbus dbus xml gnus-cloud nnimap nnmail browse-url url url-proxy
url-privacy url-expand url-methods url-history url-cookie
generate-lisp-file url-domsuf url-util url-parse auth-source cl-seq
eieio eieio-core cl-macs json map byte-opt gv bytecomp byte-compile
url-vars mail-source utf7 nnoo parse-time iso8601 gnus-spec gnus-int
gnus-range gnus-win gnus nnheader range wid-edit mh-e mh-buffers
mh-loaddefs message sendmail 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 rfc2047 rfc2045 mm-util ietf-drums
mail-prsvr mailabbrev mail-utils gmm-utils mailheader server timeclock
noutline outline icons cc-mode cc-fonts cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs advice shell pcomplete
comint subr-x ansi-osc ansi-color ring xcscope delsel time vc
cl-loaddefs cl-lib vc-dispatcher mdk-hacks rmc iso-transl tooltip cconv
eldoc paren electric uniquify ediff-hook vc-hooks lisp-float-type
elisp-mode mwheel term/x-win x-win term/common-win x-dnd touch-screen
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 theme-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 inotify
dynamic-setting system-font-setting font-render-setting cairo x-toolkit
x multi-tty move-toolbar make-network-process emacs)

Memory information:
((conses 16 636507 146821) (symbols 48 36779 9)
 (strings 32 146543 17478) (string-bytes 1 4855597) (vectors 16 96383)
 (vector-slots 8 1864368 116321) (floats 8 670 9602)
 (intervals 56 25189 271) (buffers 984 92))