feat(tmux): improve tmux ssh behavior

tmux/scripts/tmux-ssher

@@ -1,24 +1,47 @@
 #!/usr/bin/env bash
 
-if [[ $# -eq 1 ]]; then
-    selected=$1
+# open (or switch to) a tmux session running ssh to a host
+#   tmux-ssher [host [luks]]
+
+if [[ $# -ge 1 ]]; then
+    host=$1
+    profile=${2:-}
 else
-    selected="$(~/.config/bin/ssh-menu -s)"
+    IFS=$'\t' read -r host profile < <(~/.config/bin/ssh-menu -s)
 fi
 
-if [[ -z $selected ]]; then
+if [[ -z $host ]]; then
     exit 0
 fi
 
-selected_name="ssh_$selected"
+# session names cannot contain . or :
+name=${host//[.:]/_}
 
-if [[ -z $TMUX ]] && ! tmux list-sessions 2>/dev/null; then
-    tmux new-session -s "$selected_name" ssh "$selected"
-    exit 0
+# an unlock session is short-lived and must not collide with a live ssh session
+if [[ $profile == luks ]]; then
+    session="unlock_$name"
+    args=(-P luks "$host")
+else
+    session="ssh_$name"
+    args=("$host")
 fi
 
-if ! tmux has-session -t="$selected_name" 2>/dev/null; then
-    tmux new-session -ds "$selected_name" ssh "$selected"
+# on failure keep the window until enter, so the error stays readable (e.g.
+# publickey denied because the yubikey is not inserted); tmux.conf's
+# detach-on-destroy then returns to the previous session. bash, not the tmux
+# default shell, so read -p behaves
+cmd="bash -c 'ssh \"\$@\" || { rc=\$?; echo; read -rp \"ssh exited \$rc, press enter to close \"; }' _$(printf ' %q' "${args[@]}")"
+
+if ! tmux has-session -t="$session" 2>/dev/null; then
+    tmux new-session -ds "$session" -n "$host" "$cmd"
+    # tmux.conf's c / " / % bindings read this to open more panes on the same host
+    if [[ $profile != luks ]]; then
+        tmux set-option -t "=$session:" @ssh_host "$host"
+    fi
 fi
 
-tmux switch-client -t "$selected_name"
+if [[ -z $TMUX ]]; then
+    tmux attach-session -t "=$session"
+else
+    tmux switch-client -t "=$session"
+fi

tmux/tmux.conf

@@ -13,6 +13,10 @@ set -g prefix C-s
 set -g base-index 1
 set -g focus-events on
 set -g update-environment "SSH_AUTH_SOCK SSH_CONNECTION SSH_TTY DISPLAY"
+# when a session dies under the client (e.g. a failed ssh in tmux-ssher) go to
+# the most recently used session instead of detaching. not "previous": that
+# path crashes the whole server on 3.7b+ (tmux issue 5344, fixed after 3.7c)
+set -g detach-on-destroy off
 
 # status bar
 set -g status-style 'bg=default fg=default'
@@ -37,6 +41,13 @@ bind j select-pane -D
 bind h select-pane -L
 bind l select-pane -R
 
+# windows and panes: inside an ssh session (@ssh_host set by tmux-ssher) new
+# panes open on the same host over the multiplexed connection.
+# new-window/split-window do not expand formats in their command, run-shell does
+bind c if-shell -F "#{@ssh_host}" 'run-shell "tmux new-window -t \"#{session_name}\" -n \"#{@ssh_host}\" \"ssh #{@ssh_host}\""' "new-window"
+bind '"' if-shell -F "#{@ssh_host}" 'run-shell "tmux split-window -v -t \"#{pane_id}\" \"ssh #{@ssh_host}\""' "split-window -v"
+bind % if-shell -F "#{@ssh_host}" 'run-shell "tmux split-window -h -t \"#{pane_id}\" \"ssh #{@ssh_host}\""' "split-window -h"
+
 # reload
 bind r source-file "$XDG_CONFIG_HOME/tmux/tmux.conf"