An error with ports when using a subgraph
When I declare two nodes in a subgraph, and make two edges between them, of which the second has a specified `arrowhead':
digraph G {
node[shape=record]
dpi = 80
rankdir = LR
{ rank = same;
BT[label="M_BLOCKED_TRANSACTIONS|<cn>BLOCKED_CONNECTION_ID\l|<tr>LOCK_OWNER_UPDATE_TRANSACTION_ID\l"];
TR[label="M_TRANSACTIONS_|<cn>CONNECTION_ID\l|<tr>UPDATE_TRANSACTION_ID\l"];
}
BT:cn -> TR:cn;
BT:tr -> TR:tr[arrowhead=crow];
}
graphviz ignores the arrowhead
setting and prints strange warnings:
Warning: Arrow type "tr" unknown - ignoring
Warning: Arrow type "cn" unknown - ignoring