add supporting node presets in group trees

ui/presets.py

@@ -336,7 +336,7 @@ def description(cls, context, properties):
         return "Load node settings from the preset `{}' (overwrite current settings)".format(properties.preset_name)
 
     def execute(self, context):
-        ntree = context.space_data.node_tree
+        ntree = context.space_data.path[-1].node_tree  # in case if the node in a node group
         node = ntree.nodes[self.node_name]
         id_tree = ntree.name
         ng = bpy.data.node_groups[id_tree]

utils/sv_json_struct.py

@@ -11,6 +11,7 @@
 import sys
 from abc import abstractmethod, ABC
 from enum import Enum, auto
+from itertools import chain
 from typing import Type, Generator, TYPE_CHECKING, Dict, Tuple, Optional, List, Any
 
 import bpy
@@ -73,7 +74,7 @@ def grab_from_module(cls) -> StructFactory:
         module_classes = inspect.getmembers(sys.modules[__name__],
                                             lambda member: inspect.isclass(member) and member.__module__ == __name__)
         for class_name, module_class in module_classes:
-            if hasattr(module_class, 'type') and module_class.type in StrTypes:
+            if hasattr(module_class, 'type') and isinstance(module_class.type, StrTypes):
                 factory_classes.append(module_class)
         return cls(factory_classes)
 
@@ -363,6 +364,12 @@ def build(self, node):
             for node in tree.nodes:
                 imported_structs[StrTypes.NODE, tree.name, node.name] = node.name
 
+            # in case the node is inside group tree it should be also imported with its sockets
+            # to be able connect links to group out/in nodes
+            imported_structs[StrTypes.TREE, '', tree.name] = tree.name
+            for sock in chain(tree.inputs, tree.outputs):
+                imported_structs[StrTypes.INTERFACE, tree.name, sock.identifier] = sock.identifier
+
             # import the node and rebuild the links if possible
             node_struct.build(node, factories, imported_structs)
             node.location = location  # return to initial position, it has to be after node build