Override ^p/^n in agent session to switch between root windows

agent-sync.sh

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+# Move the client that opened the agent popup to the root window matching the
+# agent session's current window. Installed by agent.sh as the agent session's
+# session-window-changed hook, so it runs for any window change made inside the
+# popup: <prefix>C-n, <prefix>C-p, select-window, choose-tree or the mouse.
+#
+# Set @agent_follow_session to "off" to keep the opening client in the session
+# it is already on, never switching it to the session owning the match.
+
+set -e
+
+# Fields are joined with a unit separator, not a tab: `read` folds runs of tabs
+# and spaces even when IFS names them, so an unset option in the middle would
+# silently shift every field after it.
+us=$'\x1f'
+
+# Everything recorded about the agent session's current window, in one
+# round-trip. Format lookups rather than show-option, so unset user options come
+# back empty instead of logging "invalid option" into the tmux message log.
+state=$(tmux display-message -p -t agent "#{session_attached}$us#{@agent_dir}\
+$us#{@agent_origin_window}$us#{@agent_popup_client}$us#{@agent_follow_session}" \
+  2>/dev/null || true)
+IFS=$us read -r attached agent_dir origin_window popup_client follow <<<"$state"
+
+# Only sync while a popup is actually attached. Without this guard the
+# detach-client + kill-window agent-cmd.sh performs when an agent exits would
+# drag the root client to whichever window tmux picks next.
+[ "${attached:-0}" -gt 0 ] || exit 0
+[ -n "$agent_dir" ] || exit 0
+
+# An empty session means the recorded client has since gone away.
+client_session=""
+if [ -n "$popup_client" ]; then
+  client_session=$(tmux list-clients -F "#{client_name}$us#{session_name}" \
+    | awk -v FS="$us" -v client="$popup_client" '$1 == client { print $2; exit }')
+fi
+
+target_window=""
+target_session=""
+
+# Prefer the recorded origin window, as long as it still exists.
+if [ -n "$origin_window" ]; then
+  while IFS=$us read -r window_id session_name; do
+    if [ "$window_id" = "$origin_window" ] && [ "$session_name" != agent ]; then
+      target_window=$window_id
+      target_session=$session_name
+      break
+    fi
+  done < <(tmux list-windows -a -F "#{window_id}$us#{session_name}")
+fi
+
+# Otherwise match the recorded directory against root windows. This covers agent
+# windows created before origin recording existed, and root windows that have
+# been recreated since.
+if [ -z "$target_window" ]; then
+  seen_window=""
+  while IFS=$us read -r window_id session_name start_path current_path; do
+    # Panes are listed grouped by window in index order, so the first row for a
+    # window is its first pane.
+    [ "$window_id" != "$seen_window" ] || continue
+    seen_window=$window_id
+    [ "$session_name" != agent ] || continue
+    [ "$start_path" = "$agent_dir" ] || [ "$current_path" = "$agent_dir" ] || continue
+    # Prefer a window in the session the opening client is already on.
+    if [ "$session_name" = "$client_session" ]; then
+      target_window=$window_id
+      target_session=$session_name
+      break
+    fi
+    if [ -z "$target_window" ]; then
+      target_window=$window_id
+      target_session=$session_name
+    fi
+  done < <(tmux list-panes -a -F "#{window_id}$us#{session_name}\
+$us#{pane_start_path}$us#{pane_current_path}")
+fi
+
+# No match: leave the root sessions alone rather than inventing a window.
+[ -n "$target_window" ] || exit 0
+
+# Window ids are server-global, so this moves the owning session whichever
+# client happens to be on it.
+tmux select-window -t "$target_window" 2>/dev/null || exit 0
+
+# Selecting is enough when the client is already on the target session.
+[ -n "$client_session" ] || exit 0
+[ "$follow" != off ] || exit 0
+if [ -n "$target_session" ] && [ "$target_session" != "$client_session" ]; then
+  tmux switch-client -c "$popup_client" -t "$target_session"
+fi