exclude backdropNode when process node insert

Author: ArnoChenFx

NodeGraphQt/base/graph.py

@@ -12,7 +12,7 @@
 from NodeGraphQt.base.factory import NodeFactory
 from NodeGraphQt.base.menu import NodeGraphMenu, NodesMenu
 from NodeGraphQt.base.model import NodeGraphModel
-from NodeGraphQt.base.node import NodeObject
+from NodeGraphQt.base.node import NodeObject, BaseNode
 from NodeGraphQt.base.port import Port
 from NodeGraphQt.constants import (DRAG_DROP_ID,
                                    PIPE_LAYOUT_CURVED,
@@ -132,6 +132,10 @@ def _insert_node(self, pipe, node_id, prev_node_pos):
         """
         node = self.get_node_by_id(node_id)
 
+        # exclude the BackdropNode
+        if not isinstance(node,BaseNode):
+            return
+
         disconnected = [(pipe.input_port, pipe.output_port)]
         connected = []
 
@@ -140,7 +144,9 @@ def _insert_node(self, pipe, node_id, prev_node_pos):
                 (pipe.output_port, list(node.inputs().values())[0].view)
             )
         if node.outputs():
-            connected.append((node.output(0).view, pipe.input_port))
+            connected.append(
+                (list(node.outputs().values())[0].view, pipe.input_port)
+            )
 
         self._undo_stack.beginMacro('inserted node')
         self._on_connection_changed(disconnected, connected)