Subject: bug#34127: 26.1.91; Redisplay issues with tramp

From: Tim Blackman <[email-masked]>
Date: Fri, 18 Jan 2019 17:02:04 -0500

I've been noticing various display anomalies when using the latest Emacs
26.1.91 pretest. Some cases are hard to capture or categorize, but it
seems like I'm seeing more "flashing" for redisplay than I usually do.

The case I was able to capture was when using tramp.

If I create a new tramp connection (after calling M-x
tramp-cleanup-all-connections), I see a strangely blank screen from
after calling the command (say C-x C-f "/-:slc:") until the directory
gets displayed. Please see the attached picture.

That blank screen behavior is new. In 26.1, the frame contents continue
to be displayed while the command is running.

- Tim

In GNU Emacs 26.1.91 (build 1, x86_64-apple-darwin14.5.0, NS appkit-1348.17 Version 10.10.5 (Build 14F2511))
 of 2019-01-07 built on builder10-10.porkrind.org
Windowing system distributor 'Apple', version 10.3.1561
Recent messages:
Tramp: Sending command ‘exec ssh   -o ControlMaster=auto -o ControlPath='tramp.%C' -o ControlPersist=no -e none slc’
Tramp: Waiting for prompts from remote shell...done
Tramp: Found remote shell prompt on ‘slc’
Tramp: Opening connection for slc using scp...done
Directory has changed on disk; type g to update Dired
Tramp: Opening connection for slc using scp...
Tramp: Sending command ‘exec ssh   -o ControlMaster=auto -o ControlPath='tramp.%C' -o ControlPersist=no -e none slc’
Tramp: Waiting for prompts from remote shell...done
Tramp: Found remote shell prompt on ‘slc’
Tramp: Opening connection for slc using scp...done

Configured using:
 'configure --with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp' --with-modules'

Configured features:
NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES THREADS

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

Major mode: Text

Minor modes in effect:
  diff-auto-refine-mode: t
  flyspell-mode: t
  global-subword-mode: t
  subword-mode: t
  shell-dirtrack-mode: t
  show-paren-mode: t
  delete-selection-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-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
  auto-fill-function: do-auto-fill
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow emacsbug sendmail debug tabify cl-print help-fns radix-tree
compare-w conf-mode sort ffap tramp-cmds sh-script executable rng-xsd
xsd-regexp rng-cmpct rng-nxml rng-valid rng-loc rng-uri rng-parse
nxml-parse rng-match rng-dt rng-util rng-pttrn nxml-ns nxml-mode
nxml-outln nxml-rap nxml-util nxml-enc xmltok mhtml-mode css-mode smie
color eww mm-url gnus nnheader wid-edit url-queue shr svg xml ediff-vers
ediff-merg ediff-wind ediff-diff ediff-mult ediff-help ediff-init
ediff-util ediff vc-git browse-url files-x tramp-cache tramp-sh
iso-transl mail-extr vc-annotate log-edit message rmc puny rfc822 mml
mml-sec epa derived epg gnus-util rmail rmail-loaddefs mm-decode
mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 mm-util
ietf-drums mail-prsvr mailabbrev mail-utils gmm-utils mailheader
diff-mode dabbrev js sgml-mode dom imenu grep dired-aux dired
dired-loaddefs misearch multi-isearch add-log log-view pcvs-util
cl-extra help-mode vc pulse vc-dispatcher cc-mode cc-fonts cc-guess
cc-menus cc-cmds etags xref project thingatpt ssh compile vc-hg
pcmpl-unix vc-filewise vc-rcs flyspell ispell elec-pair man server
cap-words superword subword cc-styles cc-align cc-engine cc-vars cc-defs
edmacro kmacro restclient noutline outline easy-mmode json map url
url-proxy url-privacy url-expand url-methods url-history url-cookie
url-domsuf url-util mailcap redo+ tjb-env tjb-misc-2 timezone tjb-misc
cl tramp tramp-compat tramp-loaddefs trampver shell pcomplete comint
ansi-color ring parse-time format-spec advice paren time delsel
cus-start cus-load finder-inf rainbow-mode-autoloads package easymenu
epg-config url-handlers url-parse auth-source cl-seq eieio eieio-core
cl-macs eieio-loaddefs password-cache url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib time-date tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win
ucs-normalize mule-util term/common-win 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 threads kqueue cocoa ns multi-tty make-network-process emacs)

Memory information:
((conses 16 1651578 380351)
 (symbols 48 54590 3)
 (miscs 40 8950 10647)
 (strings 32 114959 130840)
 (string-bytes 1 9571902)
 (vectors 16 71559)
 (vector-slots 8 2252190 163320)
 (floats 8 436 1189)
 (intervals 56 239444 12400)
 (buffers 992 466))