Fixed issue with nested Clusters and Cluster >> Node edges

diagrams/__init__.py

@@ -67,28 +67,40 @@ class _Cluster:
         setcluster(self)
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    def __exit__(self, *args):
         setcluster(self._parent)
 
-        for nodeid, node in self.nodes.items():
+        if not (self.nodes or self.subgraphs):
-            self.dot.node(nodeid, label=node['label'], **node['attrs'])
+            return
 
-        for dot in self.subgraphs:
+        for node in self.nodes.values():
-            self.dot.subgraph(dot)
+            self.dot.node(node.nodeid, label=node.label, **node._attrs)
+
+        for subgraph in self.subgraphs:
+            self.dot.subgraph(subgraph.dot)
 
         if self._parent:
-            self._parent.subgraph(self.dot)
+            self._parent.remove_node(self.nodeid)
+            self._parent.subgraph(self)
 
-    def node(self, nodeid: str, label: str, **attrs) -> None:
+    def node(self, node: "Node") -> None:
         """Create a new node."""
-        self.nodes[nodeid] = {'label': label, 'attrs': attrs}
+        self.nodes[node.nodeid] = node
 
     def remove_node(self, nodeid: str) -> None:
         del self.nodes[nodeid]
 
-    def subgraph(self, dot: Digraph) -> None:
+    def subgraph(self, subgraph: "_Cluster") -> None:
         """Create a subgraph for clustering"""
-        self.subgraphs.append(dot)
+        self.subgraphs.append(subgraph)
+
+    @property
+    def nodes_iter(self):
+        if self.nodes:
+            yield from self.nodes.values()
+        if self.subgraphs:
+            for subgraph in self.subgraphs:
+                yield from subgraph.nodes_iter
 
     def _validate_direction(self, direction: str):
         direction = direction.upper()
@@ -212,20 +224,20 @@ class Diagram(_Cluster):
         super().__enter__()
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    def __exit__(self, *args):
-        super().__exit__(exc_type, exc_value, traceback)
+        super().__exit__(*args)
         setdiagram(None)
 
-        for nodes, edge in self.edges.items():
+        for (node1, node2), edge in self.edges.items():
-            node1, node2 = nodes
+            cluster_node1 = next(node1.nodes_iter, None)
-            nodeid1, nodeid2 = node1.nodeid, node2.nodeid
+            if cluster_node1:
-            if node1.nodes:
+                edge._attrs['ltail'] = node1.nodeid
-                edge._attrs['ltail'] = nodeid1
+                node1 = cluster_node1
-                nodeid1 = next(iter(node1.nodes.keys()))
+            cluster_node2 = next(node2.nodes_iter, None)
-            if node2.nodes:
+            if cluster_node2:
-                edge._attrs['lhead'] = nodeid2
+                edge._attrs['lhead'] = node2.nodeid
-                nodeid2 = next(iter(node2.nodes.keys()))
+                node2 = cluster_node2
-            self.dot.edge(nodeid1, nodeid2, **edge.attrs)
+            self.dot.edge(node1.nodeid, node2.nodeid, **edge.attrs)
 
         self.render()
         # Remove the graphviz file leaving only the image.
@@ -332,11 +344,10 @@ class Node(_Cluster):
         self._attrs.update(attrs)
 
         # If a node is in the cluster context, add it to cluster.
-        self._parent.node(self._id, self.label, **self._attrs)
+        self._parent.node(self)
 
     def __enter__(self):
         super().__enter__()
-        setcluster(self)
 
         # Set attributes.
         for k, v in self._default_graph_attrs.items():
@@ -360,17 +371,10 @@ class Node(_Cluster):
 
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    def __exit__(self, *args):
-        if not (self.nodes or self.subgraphs):
+        super().__exit__(*args)
-            return
+        self._id = "cluster_" + self.nodeid
-
+        self.dot.name = self.nodeid
-        self._parent.remove_node(self._id)
-
-        self._id = "cluster_" + self._id
-        self.dot.name = self._id
-
-        super().__exit__(exc_type, exc_value, traceback)
-
 
     def __repr__(self):
         _name = self.__class__.__name__