From a2d0779088527ea3d261e9ad5c483c3a06ee9368 Mon Sep 17 00:00:00 2001
From: Matthew Slowe <foo@mafoo.org.uk>
Date: Sun, 24 Jan 2021 17:15:01 +0000
Subject: [PATCH] clear a topic rather than publish a "-"

---
 update-berths.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/update-berths.pl b/update-berths.pl
index 952a863..a5e2946 100755
--- a/update-berths.pl
+++ b/update-berths.pl
@@ -85,7 +85,7 @@ sub set_berth($$$) {
 
 sub clear_berth($$) {
     my ($area, $berth) = @_;
-    publish(sprintf("berths/%s/%s", $area||"-", $berth || "-"), "-");
+    publish(sprintf("berths/%s/%s", $area||"-", $berth || "-"), undef);
 }
 
 sub publish($$) {