fixup! Allow to collapse parallel edges in graphs.

src/graphviewer/graphviewer.py

@@ -8,7 +8,7 @@
 from networkx import DiGraph
 
 from macrogen import MacrogenesisInfo, write_dot
-from macrogen.graphutils import remove_edges, simplify_timeline, expand_edges, collapse_edges
+from macrogen.graphutils import remove_edges, simplify_timeline, expand_edges, collapse_edges, collapse_parallel_edges
 
 app = Flask(__name__)
 
@@ -73,7 +73,7 @@ def prepare_agraph():
                 flash('Cannot produce DAG – subgraph is not acyclic!?', 'error')
         g = simplify_timeline(g)
         if collapse:
-            g = collapse_edges(g)
+            g = collapse_parallel_edges(g)
         g.add_nodes_from(nodes)
         if order:
             g = info.order_graph(g)

src/macrogen/graphutils.py

@@ -105,15 +105,15 @@ def collapse_parallel_edges(graph: nx.MultiDiGraph) -> nx.MultiDiGraph:
     """
     result = nx.MultiDiGraph()
     result.add_nodes_from(graph.nodes)
-    for u, v in set(graph.edges):
+    for u, v in set(graph.edges(keys=False)):
         parallel_edges = list(graph[u][v].values())
         attrs = dict(parallel_edges[0])
         if len(parallel_edges) > 1:
             attrs['source'] = [e['source'] for e in parallel_edges]
-            attrs['comment'] = '\n'.join(e['comment'] for e in parallel_edges)
+            attrs['comment'] = '\n'.join(e.get('comment', '') for e in parallel_edges)
             attrs['weight'] = sum(e['weight'] for e in parallel_edges)
             attrs['iweight'] = 1/attrs['weight']
-        result.add_edge(u, v, *attrs)
+        result.add_edge(u, v, **attrs)
     return result