My emacs derivation seems to have terminal issues I can't figure out

[573]

When I start the emacs from my derivation with -Q and then move left on the line currently edited and try to insert different text the cursor jumps to some column left of the position I currently type. C-l rearranges the also garbled text so the upstream operators told me this should more or less be a problem with the TERM variable I set only that I did not set one.

Trying the same in termux with just emacs installed (pkg install emacs) I could not observe the behaviour, but also TERM is no different from mine (n-o-d).

FWIW I even tried installing emacs via home-manager on termux to test my derivation there but that's a different story.

This haunts me for ages, so is a demo of the behaviour, visible when I start typing the word "useless" (ctrl-l in video rearranges the text temporarily which is kind of but not a satisfying workaround).

[t184256]

Does it go away if you run it in tmux with `TERM=tmux`?

[573]

Problem persisting, commands used:

nix run .#nixOnDroidConfigurations.sams9.pkgs.tmux -- new-session -s nix-on-droid -d
TERM=tmux nix run .#nixOnDroidConfigurations.sams9.pkgs.emacs --impure

[573]

infocmp output is identical on both n-o-d and default termux, see

[573]

using termux.properties from upstream did not fix the issue in question.

[573]

Related, but not a fix for OP: https://github.com/lotabout/skim/blob/cd1f85710cd17720100ff3813ba7a6865a2db64f/README.md#no-line-feed-issues-with-nix--freebsd-termux / https://discourse.nixos.org/t/error-with-terminfo-when-running-bash-with-nix-run-on-nixos/5660

export TERMINFO=/data/data/com.termux.nix/files/usr/etc/profiles/per-user/nix-on-droid/share/terminfo
for n in {1..10}; do echo "$n"; done | nix run nixpkgs#skim

[573]

After figuring out that zellij in principal solves all my belated issues described above, but the version currently in nixos-unstable not working anymore I invented a very ugly yet effective workaround, note that it involves starting a screen session that terminates for whatever reason right in front of the emacs - side effect no more jumping cursors / garbled lines in emacs so far ref.:

pkgs.runCommand "emacs-no-el" {
	nativeBuildInputs = [ pkgs.makeWrapper ]; } ''
          mkdir -p $out/bin
          makeWrapper ${config.custom.programs.emacs-no-el.finalPackage.outPath}/bin/emacs $out/bin/emacs-no-el \
	    --argv0 emacs ${optionalString (isLinux && isAarch64) "--run ${pkgs.screen}/bin/screen"} --set TERM xterm-256color
        ''

One possible reproduction of the problem before this hack applied was typing Alt-: then starting to type an expression to evaluate say (getenv "TERM") doing as follows (geTABTOCOMPLETE :: triggering cursor jump, same when (getTABTOCOMPLETE resulting cleanly at first glance in (getenv but as soon as typing (getenv " the first double quote cursor jumping again the front of the whole expression.
No config show-paren-mode whatsoever helped. Typing Alt-l at any time was also not a viable option. Setting TERM differently was being ignored by emacs. The territory of compiling *.ti files using tic also seemed not viable to enter right now.

For later ref., keymap for zellij I used with version in nixos-24.05

//
// THIS FILE WAS AUTOGENERATED BY ZELLIJ, THE PREVIOUS FILE AT THIS LOCATION WAS COPIED TO: /home/nixos/.config/zellij/config.kdl.bak
//

// The only keybindings in the normal mode are:
// - `C-space` to go into the tmux mode
// - `C-n` for a new pane
// - `C-t` for a new tab
// - `A-[` & `A-]` to go to the previous/next tab
// - `S-arrow` to navigate between panes

// Note: because Zellij can't read that many keys, we map some keys in
// alacritty.yml to the binding that Zellij uses. So, for example C-Space is
// mapped to F2, S+arrow are mapped to A-{hljk}, and next/previous tab are
// mapped to F5/F6.

keybinds clear-defaults=true {
    normal {
        bind "F2" { SwitchToMode "tmux"; }
    }
    resize {
        // bind "Ctrl n" { SwitchToMode "Normal"; }
        bind "h" "Left" { Resize "Increase Left"; }
        bind "j" "Down" { Resize "Increase Down"; }
        bind "k" "Up" { Resize "Increase Up"; }
        bind "l" "Right" { Resize "Increase Right"; }
        bind "H" { Resize "Decrease Left"; }
        bind "J" { Resize "Decrease Down"; }
        bind "K" { Resize "Decrease Up"; }
        bind "L" { Resize "Decrease Right"; }
        bind "=" "+" { Resize "Increase"; }
        bind "-" { Resize "Decrease"; }
    }
    pane {
        // bind "Ctrl p" { SwitchToMode "Normal"; }
        bind "h" "Left" { MoveFocus "Left"; }
        bind "l" "Right" { MoveFocus "Right"; }
        bind "j" "Down" { MoveFocus "Down"; }
        bind "k" "Up" { MoveFocus "Up"; }
        bind "p" { SwitchFocus; }
        bind "n" { NewPane; SwitchToMode "Normal"; }
        bind "d" { NewPane "Down"; SwitchToMode "Normal"; }
        bind "r" { NewPane "Right"; SwitchToMode "Normal"; }
        bind "x" { CloseFocus; SwitchToMode "Normal"; }
        bind "f" { ToggleFocusFullscreen; SwitchToMode "Normal"; }
        bind "z" { TogglePaneFrames; SwitchToMode "Normal"; }
        bind "w" { ToggleFloatingPanes; SwitchToMode "Normal"; }
        bind "e" { TogglePaneEmbedOrFloating; SwitchToMode "Normal"; }
        bind "c" { SwitchToMode "RenamePane"; PaneNameInput 0;}
    }
    move {
        // bind "Ctrl h" { SwitchToMode "Normal"; }
        bind "n" "Tab" { MovePane; }
        bind "h" "Left" { MovePane "Left"; }
        bind "j" "Down" { MovePane "Down"; }
        bind "k" "Up" { MovePane "Up"; }
        bind "l" "Right" { MovePane "Right"; }
    }
    tab {
        // bind "Ctrl t" { SwitchToMode "Normal"; }
        bind "r" { SwitchToMode "RenameTab"; TabNameInput 0; }
        bind "h" "Left" "Up" "k" { GoToPreviousTab; }
        bind "l" "Right" "Down" "j" { GoToNextTab; }
        bind "n" { NewTab; SwitchToMode "Normal"; }
        bind "x" { CloseTab; SwitchToMode "Normal"; }
        bind "s" { ToggleActiveSyncTab; SwitchToMode "Normal"; }
        bind "1" { GoToTab 1; SwitchToMode "Normal"; }
        bind "2" { GoToTab 2; SwitchToMode "Normal"; }
        bind "3" { GoToTab 3; SwitchToMode "Normal"; }
        bind "4" { GoToTab 4; SwitchToMode "Normal"; }
        bind "5" { GoToTab 5; SwitchToMode "Normal"; }
        bind "6" { GoToTab 6; SwitchToMode "Normal"; }
        bind "7" { GoToTab 7; SwitchToMode "Normal"; }
        bind "8" { GoToTab 8; SwitchToMode "Normal"; }
        bind "9" { GoToTab 9; SwitchToMode "Normal"; }
        bind "Tab" { ToggleTab; }
    }
    scroll {
        bind "Ctrl s" { SwitchToMode "Normal"; }
        bind "e" { EditScrollback; SwitchToMode "Normal"; }
        bind "s" { SwitchToMode "EnterSearch"; SearchInput 0; }
        // bind "Ctrl c" { ScrollToBottom; SwitchToMode "Normal"; }
        bind "j" "Down" { ScrollDown; }
        bind "k" "Up" { ScrollUp; }
        bind "Ctrl f" "PageDown" "Right" "l" { PageScrollDown; }
        bind "Ctrl b" "PageUp" "Left" "h" { PageScrollUp; }
        bind "d" { HalfPageScrollDown; }
        bind "u" { HalfPageScrollUp; }
        // uncomment this and adjust key if using copy_on_select=false
        // bind "Alt c" { Copy; }
    }
    search {
        bind "Ctrl s" { SwitchToMode "Normal"; }
        // bind "Ctrl c" { ScrollToBottom; SwitchToMode "Normal"; }
        bind "j" "Down" { ScrollDown; }
        bind "k" "Up" { ScrollUp; }
        bind "Ctrl f" "PageDown" "Right" "l" { PageScrollDown; }
        bind "Ctrl b" "PageUp" "Left" "h" { PageScrollUp; }
        bind "d" { HalfPageScrollDown; }
        bind "u" { HalfPageScrollUp; }
        bind "n" { Search "down"; }
        bind "p" { Search "up"; }
        bind "c" { SearchToggleOption "CaseSensitivity"; }
        bind "w" { SearchToggleOption "Wrap"; }
        bind "o" { SearchToggleOption "WholeWord"; }
    }
    entersearch {
        bind "Esc" { SwitchToMode "Scroll"; }
        bind "Enter" { SwitchToMode "Search"; }
    }
    renametab {
        // bind "Ctrl c" { SwitchToMode "Normal"; }
        bind "Esc" { UndoRenameTab; SwitchToMode "Tab"; }
    }
    renamepane {
        // bind "Ctrl c" { SwitchToMode "Normal"; }
        bind "Esc" { UndoRenamePane; SwitchToMode "Pane"; }
    }
    session {
        bind "Ctrl o" { SwitchToMode "Normal"; }
        bind "Ctrl s" { SwitchToMode "Scroll"; }
        bind "d" { Detach; }
    }
    tmux {
        bind "p" { SwitchToMode "pane"; }
        bind "n" { SwitchToMode "resize"; }
        bind "t" { SwitchToMode "tab"; }
        bind "s" { SwitchToMode "scroll"; }
        bind "o" { SwitchToMode "session"; }
        bind "t" { SwitchToMode "tab"; }
        bind "h" { SwitchToMode "move"; }
        bind "q" { Quit; }
        bind "d" { Detach; }
        bind "Alt =" { Resize "Increase"; }
        bind "Alt +" { Resize "Increase"; }
        bind "Alt -" { Resize "Decrease"; }
    }
    shared_except "locked" {
        bind "F5" { GoToPreviousTab; }
        bind "Alt [" { GoToPreviousTab; }
        bind "F6" { GoToNextTab; }
        bind "Alt ]" { GoToNextTab; }
        bind "Alt h" { MoveFocusOrTab "Left"; }
        bind "Alt l" { MoveFocusOrTab "Right"; }
        bind "Alt j" { MoveFocus "Down"; }
        bind "Alt k" { MoveFocus "Up"; }
        bind "Ctrl t" { NewTab; }
        bind "Ctrl n" { NewPane; }
        bind "PageDown" { PageScrollDown; }
        bind "PageUp" { PageScrollUp; }
        bind "F8" { SwitchToMode "tmux"; }
        bind "F4" { SwitchToMode "locked"; }
    }
    shared_except "normal" {
        bind "F2" "Ctrl F3 c" { ScrollToBottom; SwitchToMode "normal"; }
    }
    // Esc "pops" the current mode, so we switch to normal for all modes except
    // the modes that aren't directly under `Normal` in the stack (there would
    // be a nicer way of expressing that if the config had some semantics of the
    // hierarchy / stack...)
    shared_except "normal" "entersearch" "renametab" "renamepane" {
        bind "Esc" { SwitchToMode "normal"; }
    }
}

// Plugin aliases - can be used to change the implementation of Zellij
// changing these requires a restart to take effect
plugins {
    compact-bar location="zellij:compact-bar"
    configuration location="zellij:configuration"
    filepicker location="zellij:strider" {
        cwd "/"
    }
    plugin-manager location="zellij:plugin-manager"
    session-manager location="zellij:session-manager"
    status-bar location="zellij:status-bar"
    strider location="zellij:strider"
    tab-bar location="zellij:tab-bar"
    welcome-screen location="zellij:session-manager" {
        welcome_screen true
    }
}

// Plugins to load in the background when a new session starts
// eg. "file:/path/to/my-plugin.wasm"
// eg. "https://example.com/my-plugin.wasm"
load_plugins {
}

// Use a simplified UI without special fonts (arrow glyphs)
// Options:
//   - true
//   - false (Default)
//
// simplified_ui true

// Choose the theme that is specified in the themes section.
// Default: default
//
// theme "dracula"

// Choose the base input mode of zellij.
// Default: normal
//
default_mode "locked"

// Choose the path to the default shell that zellij will use for opening new panes
// Default: $SHELL
//
// default_shell "fish"

// Choose the path to override cwd that zellij will use for opening new panes
//
// default_cwd "/tmp"

// The name of the default layout to load on startup
// Default: "default"
//
// default_layout "compact"

// The folder in which Zellij will look for layouts
// (Requires restart)
//
// layout_dir "/tmp"

// The folder in which Zellij will look for themes
// (Requires restart)
//
// theme_dir "/tmp"

// Toggle enabling the mouse mode.
// On certain configurations, or terminals this could
// potentially interfere with copying text.
// Options:
//   - true (default)
//   - false
//
// mouse_mode false

// Toggle having pane frames around the panes
// Options:
//   - true (default, enabled)
//   - false
//
// pane_frames false

// When attaching to an existing session with other users,
// should the session be mirrored (true)
// or should each user have their own cursor (false)
// (Requires restart)
// Default: false
//
// mirror_session true

// Choose what to do when zellij receives SIGTERM, SIGINT, SIGQUIT or SIGHUP
// eg. when terminal window with an active zellij session is closed
// (Requires restart)
// Options:
//   - detach (Default)
//   - quit
//
// on_force_close "quit"

// Configure the scroll back buffer size
// This is the number of lines zellij stores for each pane in the scroll back
// buffer. Excess number of lines are discarded in a FIFO fashion.
// (Requires restart)
// Valid values: positive integers
// Default value: 10000
//
// scroll_buffer_size 10000

// Provide a command to execute when copying text. The text will be piped to
// the stdin of the program to perform the copy. This can be used with
// terminal emulators which do not support the OSC 52 ANSI control sequence
// that will be used by default if this option is not set.
// Examples:
//
// copy_command "xclip -selection clipboard" // x11
// copy_command "wl-copy"                    // wayland
// copy_command "pbcopy"                     // osx
//
// copy_command "pbcopy"

// Choose the destination for copied text
// Allows using the primary selection buffer (on x11/wayland) instead of the system clipboard.
// Does not apply when using copy_command.
// Options:
//   - system (default)
//   - primary
//
// copy_clipboard "primary"

// Enable automatic copying (and clearing) of selection when releasing mouse
// Default: true
//
// copy_on_select true

// Path to the default editor to use to edit pane scrollbuffer
// Default: $EDITOR or $VISUAL
// scrollback_editor "/usr/bin/vim"

// A fixed name to always give the Zellij session.
// Consider also setting `attach_to_session true,`
// otherwise this will error if such a session exists.
// Default: <RANDOM>
//
// session_name "My singleton session"

// When `session_name` is provided, attaches to that session
// if it is already running or creates it otherwise.
// Default: false
//
// attach_to_session true

// Toggle between having Zellij lay out panes according to a predefined set of layouts whenever possible
// Options:
//   - true (default)
//   - false
//
// auto_layout false

// Whether sessions should be serialized to the cache folder (including their tabs/panes, cwds and running commands) so that they can later be resurrected
// Options:
//   - true (default)
//   - false
//
// session_serialization false

// Whether pane viewports are serialized along with the session, default is false
// Options:
//   - true
//   - false (default)
//
// serialize_pane_viewport false

// Scrollback lines to serialize along with the pane viewport when serializing sessions, 0
// defaults to the scrollback size. If this number is higher than the scrollback size, it will
// also default to the scrollback size. This does nothing if `serialize_pane_viewport` is not true.
//
// scrollback_lines_to_serialize 10000

// Enable or disable the rendering of styled and colored underlines (undercurl).
// May need to be disabled for certain unsupported terminals
// (Requires restart)
// Default: true
//
// styled_underlines false

// How often in seconds sessions are serialized
//
// serialization_interval 10000

// Enable or disable writing of session metadata to disk (if disabled, other sessions might not know
// metadata info on this session)
// (Requires restart)
// Default: false
//
// disable_session_metadata false

// Enable or disable support for the enhanced Kitty Keyboard Protocol (the host terminal must also support it)
// (Requires restart)
// Default: true (if the host terminal supports it)
//
// support_kitty_keyboard_protocol false