bug#45256: Viewing images over network using TRAMP (errors and unexpected prompts)

[Mikhail P]

Greetings.

I am experiencing problems with viewing remote images. When resizing an image (e.g. by resizing Emacs frame) Emacs occasionally (approximately ~30% reproducibility) can prompt ... changed on disk; really edit the buffer? which does not make a lot of sense. Regardless of my response Emacs outputs errors, lags for several seconds and only after that resizes the image.

I am using currently most recent commit on TRAMP repo (69844458e33b5dcae53de249d9d82c59a5876055) containing some necessary fixes. Prior to these fixes Emacs could occasionally stall on resizing remote image and only interruption with C-g could help (or sometimes making Emacs completely unresponsive). Also attaching TRAMP debug file which I hope exposes the problem.

As far as I could understand from my conversation with TRAMP devs while working on the fixes there are problems with functions called on idle-timer in image mode ... 😬

Below as a quotation is what report-emacs-bug has generated.

To make this report I ran emacs as follows:

emacs -Q --eval="(progn (add-to-list 'load-path \"/home/mikpom/Dropbox/.config/emacs-plugins/tramp\") (require 'tramp) (setq tramp-verbose 10) (setq tramp-use-ssh-controlmaster-options nil) (setq tramp-debug-to-file t))" /ssh:horsehop:/storage1/mikpom/wizard_devel/CNV/figs/TCGA_CNV/ATP23/TCGA-02-2485.png

Thanks,

Mikhail

> In GNU Emacs 27.1 (build 1,
>       x86_64-pc-linux-gnu, GTK+ Version 3.24.22, cairo version 1.17.3)
>        of 2020-08-29 built on juergen
>       Windowing system distributor 'The X.Org Foundation', version
>       11.0.12009000
>       System Description: Arch Linux
>       
>       Recent messages:
>       Unchanged content check: (remote-file-error "Forbidden reentrant
>       call of Tramp")
>       error: "Command attempted to use minibuffer while in minibuffer"
>       Error running timer ‘image-fit-to-window’: (error "Command
>       attempted to use minibuffer while in minibuffer")
>       TCGA-02-2485.png changed on disk; really edit the buffer? (y, n, r
>       or C-h) n
>       peculiar error: File changed on disk
> /ssh:horsehop:/storage1/mikpom/wizard_devel/CNV/figs/TCGA_CNV/ATP23/TCGA-02-2485.png
>       Error running timer ‘image-fit-to-window’: (file-supersession
>       "File changed on disk
> /ssh:horsehop:/storage1/mikpom/wizard_devel/CNV/figs/TCGA_CNV/ATP23/TCGA-02-2485.png")
>       Quit: "Quit", ""
>       Quit
>       Remote file error (compat): Forbidden reentrant call of Tramp [5
>       times]
>       Error running timer ‘image-fit-to-window’: (remote-file-error
>       "Forbidden reentrant call of Tramp")
>       
>       Configured using:
>        'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
>        --localstatedir=/var --with-x-toolkit=gtk3 --with-xft
>       --with-wide-int
>        --with-modules --with-cairo --with-harfbuzz 'CFLAGS=-march=x86-64
>        -mtune=generic -O2 -pipe -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
>        LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
>       
>       Configured features:
>       XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB
>       NOTIFY
>       INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
>       TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD
>       JSON
>       PDUMPER LCMS2 GMP
>       
>       Important settings:
>         value of $LANG: en_US.UTF-8
>         locale-coding-system: utf-8-unix
>       
>       Major mode: Image[png]
>       
>       Minor modes in effect:
>         shell-dirtrack-mode: t
>         tooltip-mode: t
>         global-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:
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-gvfs hides
>       /usr/share/emacs/27.1/lisp/net/tramp-gvfs
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-rclone
>       hides /usr/share/emacs/27.1/lisp/net/tramp-rclone
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-compat
>       hides /usr/share/emacs/27.1/lisp/net/tramp-compat
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-loaddefs
>       hides /usr/share/emacs/27.1/lisp/net/tramp-loaddefs
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-ftp hides
>       /usr/share/emacs/27.1/lisp/net/tramp-ftp
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-integration
>       hides /usr/share/emacs/27.1/lisp/net/tramp-integration
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp hides
>       /usr/share/emacs/27.1/lisp/net/tramp
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-sh hides
>       /usr/share/emacs/27.1/lisp/net/tramp-sh
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-cache hides
>       /usr/share/emacs/27.1/lisp/net/tramp-cache
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-adb hides
>       /usr/share/emacs/27.1/lisp/net/tramp-adb
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-archive
>       hides /usr/share/emacs/27.1/lisp/net/tramp-archive
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-cmds hides
>       /usr/share/emacs/27.1/lisp/net/tramp-cmds
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-smb hides
>       /usr/share/emacs/27.1/lisp/net/tramp-smb
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-sudoedit
>       hides /usr/share/emacs/27.1/lisp/net/tramp-sudoedit
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/tramp-uu hides
>       /usr/share/emacs/27.1/lisp/net/tramp-uu
>       /home/mikpom/Dropbox/.config/emacs-plugins/tramp/trampver hides
>       /usr/share/emacs/27.1/lisp/net/trampver
>       
>       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 text-property-search mm-decode mm-bodies mm-encode
>       mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
>       rfc2047
>       rfc2045 ietf-drums mm-util mail-prsvr mail-utils vc-hg vc-git
>       diff-mode
>       vc-bzr help-fns radix-tree cl-print backtrace help-mode find-func
>       image-mode easymenu exif tramp-sh noutline outline easy-mmode
>       tramp-cache tramp tramp-loaddefs trampver tramp-integration
>       files-x
>       tramp-compat shell pcomplete comint ansi-color ring parse-time
>       iso8601
>       time-date ls-lisp format-spec auth-source cl-seq eieio eieio-core
>       cl-macs eieio-loaddefs cl-loaddefs cl-lib password-cache json
>       subr-x map
>       seq byte-opt gv bytecomp byte-compile cconv 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 timer
>       select scroll-bar mouse jit-lock font-lock syntax facemenu
>       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
>       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 dbusbind inotify lcms2 dynamic-setting
>       system-font-setting font-render-setting cairo move-toolbar gtk
>       x-toolkit
>       x multi-tty make-network-process emacs)
>       
>       Memory information:
>       ((conses 16 238745 23438)
>        (symbols 48 9577 2)
>        (strings 32 29283 2492)
>        (string-bytes 1 1268698)
>        (vectors 16 23567)
>        (vector-slots 8 1083940 157766)
>        (floats 8 55 178)
>        (intervals 56 80877 0)
>        (buffers 1000 14))
>

files.tar.gz
Description: application/gzip