Some new notifications, mainly for active pane and current window and

session:

    pane-mode-changed
    window-pane-changed
    client-session-changed
    session-window-changed

From Joshua Brot.

cmd-switch-client.c

@@ -129,6 +129,7 @@ cmd_switch_client_exec(struct cmd *self, struct cmdq_item *item)
 	if (~item->shared->flags & CMDQ_SHARED_REPEAT)
 		server_client_set_key_table(c, NULL);
 	status_timer_start(c);
+	notify_client("client-session-changed", c);
 	session_update_activity(s, NULL);
 	gettimeofday(&s->last_attached_time, NULL);
 

control-notify.c

@@ -59,14 +59,27 @@ control_notify_input(struct client *c, struct window_pane *wp,
 	}
 }
 
+void
+control_notify_pane_mode_changed(int pane)
+{
+	struct client	*c;
+
+	TAILQ_FOREACH(c, &clients, entry) {
+		if (!CONTROL_SHOULD_NOTIFY_CLIENT(c))
+			continue;
+
+		control_write(c, "%%pane-mode-changed %%%u", pane);
+	}
+}
+
 void
 control_notify_window_layout_changed(struct window *w)
 {
-	struct client		*c;
+	struct client	*c;
-	struct session		*s;
+	struct session	*s;
-	struct winlink		*wl;
+	struct winlink	*wl;
-	const char		*template;
+	const char	*template;
-	char			*cp;
+	char		*cp;
 
 	template = "%layout-change #{window_id} #{window_layout} "
 	    "#{window_visible_layout} #{window_flags}";
@@ -96,6 +109,20 @@ control_notify_window_layout_changed(struct window *w)
 	}
 }
 
+void
+control_notify_window_pane_changed(struct window *w)
+{
+	struct client	*c;
+
+	TAILQ_FOREACH(c, &clients, entry) {
+		if (!CONTROL_SHOULD_NOTIFY_CLIENT(c))
+			continue;
+
+		control_write(c, "%%window-pane-changed @%u %%%u", w->id,
+		    w->active->id);
+	}
+}
+
 void
 control_notify_window_unlinked(__unused struct session *s, struct window *w)
 {
@@ -154,15 +181,27 @@ control_notify_window_renamed(struct window *w)
 }
 
 void
-control_notify_client_session_changed(struct client *c)
+control_notify_client_session_changed(struct client *cc)
 {
+	struct client	*c;
 	struct session	*s;
 
-	if (!CONTROL_SHOULD_NOTIFY_CLIENT(c) || c->session == NULL)
+	if (cc->session == NULL)
 		return;
-	s = c->session;
+	s = cc->session;
 
-	control_write(c, "%%session-changed $%u %s", s->id, s->name);
+	TAILQ_FOREACH(c, &clients, entry) {
+		if (!CONTROL_SHOULD_NOTIFY_CLIENT(c) || c->session == NULL)
+			continue;
+
+		if (cc == c) {
+			control_write(c, "%%session-changed $%u %s", s->id,
+			    s->name);
+		} else {
+			control_write(c, "%%client-session-changed %s $%u %s",
+			    cc->name, s->id, s->name);
+		}
+	}
 }
 
 void
@@ -203,3 +242,17 @@ control_notify_session_closed(__unused struct session *s)
 		control_write(c, "%%sessions-changed");
 	}
 }
+
+void
+control_notify_session_window_changed(struct session *s)
+{
+	struct client	*c;
+
+	TAILQ_FOREACH(c, &clients, entry) {
+		if (!CONTROL_SHOULD_NOTIFY_CLIENT(c))
+			continue;
+
+		control_write(c, "%%session-window-changed $%u @%u", s->id,
+		    s->curw->window->id);
+	}
+}

notify.c

@@ -79,8 +79,12 @@ notify_callback(struct cmdq_item *item, void *data)
 
 	log_debug("%s: %s", __func__, ne->name);
 
+	if (strcmp(ne->name, "pane-mode-changed") == 0)
+		control_notify_pane_mode_changed(ne->pane);
 	if (strcmp(ne->name, "window-layout-changed") == 0)
 		control_notify_window_layout_changed(ne->window);
+	if (strcmp(ne->name, "window-pane-changed") == 0)
+		control_notify_window_pane_changed(ne->window);
 	if (strcmp(ne->name, "window-unlinked") == 0)
 		control_notify_window_unlinked(ne->session, ne->window);
 	if (strcmp(ne->name, "window-linked") == 0)
@@ -95,6 +99,8 @@ notify_callback(struct cmdq_item *item, void *data)
 		control_notify_session_created(ne->session);
 	if (strcmp(ne->name, "session-closed") == 0)
 		control_notify_session_closed(ne->session);
+	if (strcmp(ne->name, "session-window-changed") == 0)
+		control_notify_session_window_changed(ne->session);
 
 	notify_hook(item, ne);
 

session.c

@@ -553,6 +553,7 @@ session_set_current(struct session *s, struct winlink *wl)
 	s->curw = wl;
 	winlink_clear_flags(wl);
 	window_update_activity(wl->window);
+	notify_session("session-window-changed", s);
 	return (0);
 }
 

tmux.1

@@ -4231,6 +4231,11 @@ A notification will never occur inside an output block.
 .Pp
 The following notifications are defined:
 .Bl -tag -width Ds
+.It Ic %client-session-changed Ar client Ar session-id Ar name
+The client is now attached to the session with ID
+.Ar session-id ,
+which is named
+.Ar name .
 .It Ic %exit Op Ar reason
 The
 .Nm
@@ -4253,6 +4258,10 @@ and the window flags are
 A window pane produced output.
 .Ar value
 escapes non-printable characters and backslash as octal \\xxx.
+.It Ic %pane-mode-changed Ar pane-id
+The pane with ID
+.Ar pane-id
+has changed mode.
 .It Ic %session-changed Ar session-id Ar name
 The client is now attached to the session with ID
 .Ar session-id ,
@@ -4261,6 +4270,11 @@ which is named
 .It Ic %session-renamed Ar name
 The current session was renamed to
 .Ar name .
+.It Ic %session-window-changed Ar session-id Ar window-id
+The session with ID
+.Ar session-id
+changed its active window to the window with ID
+.Ar window-id .
 .It Ic %sessions-changed
 A session was created or destroyed.
 .It Ic %unlinked-window-add Ar window-id
@@ -4275,6 +4289,11 @@ was linked to the current session.
 The window with ID
 .Ar window-id
 closed.
+.It Ic %window-pane-changed Ar window-id Ar pane-id
+The active pane in the window with ID
+.Ar window-id
+changed to the pane with ID
+.Ar pane-id .
 .It Ic %window-renamed Ar window-id Ar name
 The window with ID
 .Ar window-id

tmux.h

@@ -2208,7 +2208,9 @@ void	control_write_buffer(struct client *, struct evbuffer *);
 /* control-notify.c */
 void	control_notify_input(struct client *, struct window_pane *,
 	    struct evbuffer *);
+void	control_notify_pane_mode_changed(int);
 void	control_notify_window_layout_changed(struct window *);
+void	control_notify_window_pane_changed(struct window *);
 void	control_notify_window_unlinked(struct session *, struct window *);
 void	control_notify_window_linked(struct session *, struct window *);
 void	control_notify_window_renamed(struct window *);
@@ -2216,6 +2218,7 @@ void	control_notify_client_session_changed(struct client *);
 void	control_notify_session_renamed(struct session *);
 void	control_notify_session_created(struct session *);
 void	control_notify_session_closed(struct session *);
+void	control_notify_session_window_changed(struct session *);
 
 /* session.c */
 extern struct sessions sessions;

window.c

@@ -355,6 +355,8 @@ window_create_spawn(const char *name, int argc, char **argv, const char *path,
 	} else
 		w->name = default_window_name(w);
 
+	notify_window("window-pane-changed", w);
+
 	return (w);
 }
 
@@ -441,11 +443,14 @@ window_set_active_pane(struct window *w, struct window_pane *wp)
 		w->active = TAILQ_PREV(w->active, window_panes, entry);
 		if (w->active == NULL)
 			w->active = TAILQ_LAST(&w->panes, window_panes);
-		if (w->active == wp)
+		if (w->active == wp) {
+			notify_window("window-pane-changed", w);
 			return (1);
+		}
 	}
 	w->active->active_point = next_active_point++;
 	w->active->flags |= PANE_CHANGED;
+	notify_window("window-pane-changed", w);
 	return (1);
 }
 
@@ -621,8 +626,10 @@ window_lost_pane(struct window *w, struct window_pane *wp)
 			if (w->active == NULL)
 				w->active = TAILQ_NEXT(wp, entry);
 		}
-		if (w->active != NULL)
+		if (w->active != NULL) {
 			w->active->flags |= PANE_CHANGED;
+			notify_window("window-pane-changed", w);
+		}
 	} else if (wp == w->last)
 		w->last = NULL;
 }
@@ -1181,6 +1188,7 @@ window_pane_set_mode(struct window_pane *wp, const struct window_mode *mode)
 	wp->flags |= (PANE_REDRAW|PANE_CHANGED);
 
 	server_status_window(wp->window);
+	notify_pane("pane-mode-changed", wp);
 	return (0);
 }
 
@@ -1200,6 +1208,7 @@ window_pane_reset_mode(struct window_pane *wp)
 	wp->flags |= (PANE_REDRAW|PANE_CHANGED);
 
 	server_status_window(wp->window);
+	notify_pane("pane-mode-changed", wp);
 }
 
 void