luci-base: gracefully handle broken firewall forwarding sections

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

modules/luci-base/luasrc/model/firewall.lua

@@ -498,11 +498,13 @@ function forwarding.dest(self)
 end
 
 function forwarding.src_zone(self)
-	return zone(self:src())
+	local z = zone(self:src())
+	return z.sid and z
 end
 
 function forwarding.dest_zone(self)
-	return zone(self:dest())
+	local z = zone(self:dest())
+	return z.sid and z
 end
 
 

modules/luci-base/luasrc/view/cbi/firewall_zoneforwards.htm

@@ -43,11 +43,12 @@
 	 ⇒ 
 	<% for _, fwd in ipairs(zone:get_forwardings_by("src")) do
 		fz = fwd:dest_zone()
-		empty = false %>
+		if fz then
+			empty = false %>
 		<label class="zonebadge" style="background-color:<%=fz:get_color()%>">
 			<strong><%=fz:name()%></strong>
 		</label>&#160;
-	<% end %>
+	<% end end %>
 	<% if empty then %>
 		<label class="zonebadge zonebadge-empty">
 			<strong><%=zone:forward():upper()%></strong>