===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/tmux/format.c,v
retrieving revision 1.288
retrieving revision 1.289
diff -u -r1.288 -r1.289
--- src/usr.bin/tmux/format.c	2021/07/13 22:09:29	1.288
+++ src/usr.bin/tmux/format.c	2021/08/12 08:05:11	1.289
@@ -1,4 +1,4 @@
-/* $OpenBSD: format.c,v 1.288 2021/07/13 22:09:29 nicm Exp $ */
+/* $OpenBSD: format.c,v 1.289 2021/08/12 08:05:11 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -929,6 +929,9 @@
 	struct window_pane	*wp = ft->wp;
 	struct grid_cell	 gc;
 
+	if (wp == NULL)
+		return (NULL);
+
 	tty_default_colours(&gc, wp);
 	return (xstrdup(colour_tostring(gc.fg)));
 }
@@ -940,6 +943,9 @@
 	struct window_pane	*wp = ft->wp;
 	struct grid_cell	 gc;
 
+	if (wp == NULL)
+		return (NULL);
+
 	tty_default_colours(&gc, wp);
 	return (xstrdup(colour_tostring(gc.bg)));
 }
@@ -3077,6 +3083,22 @@
 	if (ft->client != NULL)
 		server_client_unref(ft->client);
 	free(ft);
+}
+
+/* Log each format. */
+static void
+format_log_debug_cb(const char *key, const char *value, void *arg)
+{
+	const char	*prefix = arg;
+
+	log_debug("%s: %s=%s", prefix, key, value);
+}
+
+/* Log a format tree. */
+void
+format_log_debug(struct format_tree *ft, const char *prefix)
+{
+	format_each(ft, format_log_debug_cb, prefix);
 }
 
 /* Walk each format. */