Add next_session_id format with the next session ID, GitHub issue 3078.

4 files changed, 17 insertions, 5 deletions

diff --git a/usr.bin/tmux/format.c b/usr.bin/tmux/format.c
index ea6cd40844c..2b2a0b70b26 100644
--- a/usr.bin/tmux/format.c
+++ b/usr.bin/tmux/format.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: format.c,v 1.299 2021/10/25 21:21:16 nicm Exp $ */
+/* $OpenBSD: format.c,v 1.300 2022/02/22 11:10:41 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1650,6 +1650,13 @@ format_cb_mouse_y(struct format_tree *ft)
 	return (NULL);
 }
 
+/* Callback for next_session_id. */
+static void *
+format_cb_next_session_id(__unused struct format_tree *ft)
+{
+	return (format_printf("$%u", next_session_id));
+}
+
 /* Callback for origin_flag. */
 static void *
 format_cb_origin_flag(struct format_tree *ft)
@@ -2707,6 +2714,9 @@ static const struct format_table_entry format_table[] = {
 	{ "mouse_y", FORMAT_TABLE_STRING,
 	  format_cb_mouse_y
 	},
+	{ "next_session_id", FORMAT_TABLE_STRING,
+	  format_cb_next_session_id
+	},
 	{ "origin_flag", FORMAT_TABLE_STRING,
 	  format_cb_origin_flag
 	},
diff --git a/usr.bin/tmux/session.c b/usr.bin/tmux/session.c
index 4d0b0262889..f710bd75520 100644
--- a/usr.bin/tmux/session.c
+++ b/usr.bin/tmux/session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.90 2021/09/17 07:20:49 nicm Exp $ */
+/* $OpenBSD: session.c,v 1.91 2022/02/22 11:10:41 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -29,7 +29,7 @@
 #include "tmux.h"
 
 struct sessions		sessions;
-static u_int		next_session_id;
+u_int			next_session_id;
 struct session_groups	session_groups = RB_INITIALIZER(&session_groups);
 
 static void	session_free(int, short, void *);
diff --git a/usr.bin/tmux/tmux.1 b/usr.bin/tmux/tmux.1
index 511bd10b8de..9907c5eead5 100644
--- a/usr.bin/tmux/tmux.1
+++ b/usr.bin/tmux/tmux.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.878 2022/02/22 10:53:34 nicm Exp $
+.\" $OpenBSD: tmux.1,v 1.879 2022/02/22 11:10:41 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -5098,6 +5098,7 @@ The following variables are available, where appropriate:
 .It Li "mouse_word" Ta "" Ta "Word under mouse, if any"
 .It Li "mouse_x" Ta "" Ta "Mouse X position, if any"
 .It Li "mouse_y" Ta "" Ta "Mouse Y position, if any"
+.It Li "next_session_id" Ta "" Ta "Unique session ID for next new session"
 .It Li "origin_flag" Ta "" Ta "Pane origin flag"
 .It Li "pane_active" Ta "" Ta "1 if active pane"
 .It Li "pane_at_bottom" Ta "" Ta "1 if pane is at the bottom of window"
diff --git a/usr.bin/tmux/tmux.h b/usr.bin/tmux/tmux.h
index 1822467fcb4..99f541b0133 100644
--- a/usr.bin/tmux/tmux.h
+++ b/usr.bin/tmux/tmux.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.1160 2022/02/16 18:55:05 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.1161 2022/02/22 11:10:41 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -3118,6 +3118,7 @@ void	control_notify_session_window_changed(struct session *);
 
 /* session.c */
 extern struct sessions sessions;
+extern u_int next_session_id;
 int	session_cmp(struct session *, struct session *);
 RB_PROTOTYPE(sessions, session, entry, session_cmp);
 int		 session_alive(struct session *);