Bugfix: det_id_roles_and_msgs

The method assumed, that in the chosen communication interval, for every reply there was a request before. This is correct most of the time, but not always and can result in an error.
Now: In the above scenario, replies without requests will be skipped, resulting in the same behavior we could observe when ID2T was called without an error (in terms of output)

code/ID2TLib/CommunicationProcessor.py

@@ -125,6 +125,9 @@ class CommunicationProcessor():
         msgs, msg_id = [], 0
         # keep track of previous request to find connections
         prev_reqs = {}
+        # used to determine whether a request has been seen yet, so that replies before the first request are skipped and do not throw an error by
+        # accessing the empty dict prev_reqs (this is not a perfect solution, but it works most of the time)
+        req_seen = False
         local_init_ids = self.local_init_ids
         external_init_ids = set()
 
@@ -154,9 +157,10 @@ class CommunicationProcessor():
                 msgs.append(msg)
                 prev_reqs[msg_str] = msg_id
                 msg_id += 1
+                req_seen = True
 
             # process a reply
-            elif msg_type in {MessageType.SALITY_HELLO_REPLY, MessageType.SALITY_NL_REPLY}:
+            elif msg_type in {MessageType.SALITY_HELLO_REPLY, MessageType.SALITY_NL_REPLY} and req_seen:
                 if not self.nat and id_src in local_init_ids and id_dst not in local_init_ids:
                     # process ID's role
                     external_init_ids.add(id_dst)