Trees with reroutes

[Durman]

Problem statement

broken.zip

It seems that I messed something up in this method:

sverchok/core/update_system.py

Lines 152 to 157 in fa455c1

	def _remove_reroutes(self):
	for _node in self._from_nodes:
	if _node.bl_idname == "NodeReroute":
	# relink nodes
	from_n = self._from_nodes[_node].pop()

In the update tree data structure I remove reroutes because there is no any sense to take them into account during updating trees. The code is not complex but delicate and it seems is better to add some tests for this step.

[Durman]

This is how I think the test should look like

[zeffii]

self.inputs['some_socket'].is_linked would return False is the input is from a reroute node with no upstream connection?

      no upstream connections        
            V                                      ___________some node_________
      (reroute) --------------------------------->| o [ some_socket]            |
                                                  |_____________________________| 

[Durman]

The actual Blender tree is always unchanged so inside nodes the is_linked test will be true but update system uses its internal efficient data structure where the some_socket will be recognised as disconnected.