fix undefined behavior when using ports #406

src/PJONDefines.h

@@ -395,6 +395,14 @@ struct PJONTools {
 
   static void parse_header(const uint8_t *packet, PJON_Packet_Info &info) {
     uint8_t index = 0;
+
+    // replace passed in info with a fresh instance
+    // (initializing all values to their defaults)
+    // This is important, as we conditionally parse some info fields (e.g. Port)
+    // Those would then be left uninitialized or in an old state corresponding to
+    // the previous packet:
+    info = PJON_Packet_Info{};
+
     info.rx.id = packet[index++];
     bool extended_length = packet[index] & PJON_EXT_LEN_BIT;
     info.header = packet[index++];