bug#31099: 27.0.50; ultra long tramp entries in recentf file

[Thomas Hisch]

I have a recentf file containing only 171 lines but it's 56MB big! Due to
its large size loading and closing emacs is slowed down.

The large size is due to a few tramp entries like the following (each 
entry consumes approx 10MB):

  #("/ssh:user@host:/file1" 1 4 (match-part #("/ssh:user@host:/file2" 1 4
   ....

I guess that this is either a bug in recentf or in tramp.



In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
 of 2018-04-08 built on thomas-XPS-13-9360
Repository revision: 8df23a82042fa7dbaaa4377bc376d705595b073f
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
System Description: Ubuntu 16.04.4 LTS

Recent messages:
Invalid face attribute :bold t [64 times]
Quit
Updating buffer list...
Formats have changed, recompiling...done
Updating buffer list...done
Commands: m, u, t, RET, g, k, S, D, Q; q to quit; h for help
Saving file /home/thomas/*message*-20180408-204229...
Wrote /home/thomas/*message*-20180408-204229
Quit
Mark set

Configured using:
 'configure --prefix=/opt/emacs --with-x-toolkit=gtk3 --with-xpm
 --without-jpeg --without-gif --without-tiff'

Configured features:
XPM PNG SOUND DBUS GSETTINGS NOTIFY GNUTLS FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 THREADS

Important settings:
  value of $LC_MONETARY: de_AT.UTF-8
  value of $LC_NUMERIC: de_AT.UTF-8
  value of $LC_TIME: de_AT.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  global-ethan-wspace-mode: t
  project-persist-mode: t
  recentf-mode: t
  savehist-mode: t
  global-hi-lock-mode: t
  hi-lock-mode: t
  window-numbering-mode: t
  projectile-mode: t
  global-flycheck-mode: t
  global-undo-tree-mode: t
  undo-tree-mode: t
  evil-mode: t
  evil-local-mode: t
  flx-ido-mode: t
  magit-auto-revert-mode: t
  global-git-commit-mode: t
  async-bytecomp-package-mode: t
  yas-global-mode: t
  yas-minor-mode: t
  global-company-mode: t
  company-mode: t
  diff-auto-refine-mode: t
  pyvenv-mode: t
  override-global-mode: t
  shell-dirtrack-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  global-prettify-symbols-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  size-indication-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug sendmail ace-jump-mode cl
smart-mode-line-dark-theme sanityinc-tomorrow-night-theme ethan-wspace
url-tramp graphene-projects project-persist graphene-speedbar
graphene-helper-functions tramp-cache recentf tree-widget savehist
hi-lock term disp-table ehelp smart-mode-line rich-minority
color-theme-sanityinc-tomorrow color window-numbering which-key
visual-fill-column rg wgrep-ag wgrep org-pdfview org-element avl-tree
generator ob-python ob-gnuplot org org-macro org-footnote org-pcomplete
org-list org-faces org-entities noutline outline org-version
ob-emacs-lisp ob ob-tangle org-src ob-ref ob-lob ob-table ob-keys ob-exp
ob-comint ob-core ob-eval org-compat org-macs org-loaddefs cal-menu
calendar cal-loaddefs pdf-tools pdf-view magit-bookmark bookmark pp
jka-compr pdf-cache pdf-info tq pdf-util image-mode helm-projectile
helm-files helm-tags helm-buffers helm-grep helm-regexp helm-utils
helm-locate helm-help helm-types helm helm-source eieio-compat
helm-multi-match helm-lib projectile ibuf-ext ibuffer ibuffer-loaddefs
stickyfunc-enhance semantic/util-modes semantic/util semantic
semantic/tag semantic/lex semantic/fw mode-local cedet cc-mode cc-fonts
cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs
counsel swiper sr-speedbar speedbar sb-image ezimage dframe smex
flycheck-pycheckers flycheck find-func evil evil-integration undo-tree
diff evil-maps evil-commands reveal flyspell ispell evil-jumps
evil-command-window evil-types evil-search evil-ex evil-macros
evil-repeat evil-states evil-core evil-common rect evil-digraphs
evil-vars flx-ido fill-column-indicator magit-obsolete magit-blame
magit-stash magit-bisect magit-remote magit-commit magit-sequence
magit-notes magit-worktree magit-tag magit-merge magit-branch
magit-reset magit-collab ghub url-http tls gnutls url-gw nsm url-auth
url url-proxy url-privacy url-expand url-methods url-history url-cookie
url-domsuf url-util mailcap magit-files magit-refs magit-status magit
magit-repos magit-apply magit-wip magit-log magit-diff smerge-mode
magit-core magit-autorevert autorevert filenotify magit-process
magit-margin magit-mode git-commit magit-git magit-section magit-utils
crm magit-popup log-edit message rmc puny dired dired-loaddefs rfc822
mml mml-sec epa gnus-util rmail rmail-loaddefs 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
pcvs-util add-log with-editor async-bytecomp async server dash
highlight-function-calls yasnippet elec-pair highlight-indentation
company-oddmuse company-keywords company-etags company-gtags
company-dabbrev-code company-dabbrev company-files company-capf
company-cmake company-xcode company-clang company-semantic company-eclim
company-template company-bbdb company help-fns radix-tree elpy
find-file-in-project ivy flx delsel ivy-overlay ffap thingatpt windmove
diff-mode pyvenv esh-var esh-cmd esh-opt esh-io esh-ext esh-proc esh-arg
esh-groups eshell esh-module esh-mode esh-util elpy-shell elpy-profile
elpy-django s elpy-refactor python tramp-sh ido grep compile files-x
etags xref project cus-edit cus-start cus-load wid-edit bpr edmacro
kmacro paradox paradox-menu paradox-commit-list hydra lv paradox-execute
paradox-github paradox-core spinner use-package use-package-ensure
use-package-delight use-package-diminish use-package-bind-key bind-key
easy-mmode use-package-core tramp trampver tramp-compat tramp-loaddefs
ucs-normalize shell pcomplete comint ansi-color ring parse-time
format-spec advice xdg mule-util rx info finder-inf package let-alist
derived pcase cl-extra help-mode easymenu url-handlers url-parse
auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache json map url-vars seq byte-opt gv bytecomp byte-compile
cconv epg epg-config subr-x cl-loaddefs cl-lib 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 menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame 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 minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote dbusbind inotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 712184 54715)
 (symbols 48 54063 3)
 (miscs 40 606 253)
 (strings 32 139419 12016)
 (string-bytes 1 22991731)
 (vectors 16 120375)
 (vector-slots 8 2834870 157262)
 (floats 8 459 299)
 (intervals 56 930 386)
 (buffers 992 18)
 (heap 1024 58647 5974))
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