TT#14008 always add a=mid to media section

closes #1361

Change-Id: I8c3dfb54f47f0cfeb913f27b240eed55e2ca8154
(cherry picked from commit a4e3f96b3f)

daemon/sdp.c

@@ -2604,15 +2604,15 @@ int sdp_replace(struct sdp_chopper *chop, GQueue *sessions, struct call_monologu
 
 			copy_up_to_end_of(chop, &sdp_media->s);
 
-			if (!sdp_media->port_num || !ps->selected_sfd)
-				goto next;
-
 			if (call_media->media_id.s) {
 				chopper_append_c(chop, "a=mid:");
 				chopper_append_str(chop, &call_media->media_id);
 				chopper_append_c(chop, "\r\n");
 			}
 
+			if (!sdp_media->port_num || !ps->selected_sfd)
+				goto next;
+
 			if (proto_is_rtp(call_media->protocol))
 				insert_codec_parameters(chop, call_media);
 

t/auto-daemon-tests.pl

@@ -40,6 +40,37 @@ my ($sock_a, $sock_b, $sock_c, $sock_d, $port_a, $port_b, $ssrc, $ssrc_b, $resp,
 
 
 
+new_call;
+
+offer('a=mid on zero streams', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio 2000 RTP/AVP 0
+c=IN IP4 198.51.100.14
+a=sendrecv
+a=mid:0
+m=audio 0 RTP/AVP 0
+c=IN IP4 198.51.100.14
+a=sendrecv
+a=mid:1
+----------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=mid:0
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtcp:PORT
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=mid:1
+SDP
+
 new_call;
 my $ft1 = ft();