An Imported Material Group Node Can't be Exported Again

[Vollkornaffe]

An assertion in the recursive sub-tree collection algorithm fails.
This is because the material's node tree is always called "Shader Nodetree", and the imported tree conflicts with it.

The error message is this:

Python: Traceback (most recent call last):
  File "/home/lars/.config/blender/5.0/extensions/vscode_development/tree_clipper_addon/operators_export.py", line 41, in invoke
    return self.execute(context)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/lars/.config/blender/5.0/extensions/vscode_development/tree_clipper_addon/operators_export.py", line 47, in execute
    _INTERMEDIATE_EXPORT_CACHE = ExportIntermediate(
                                 ^^^^^^^^^^^^^^^^^^^
  File "/home/lars/.config/blender/5.0/extensions/vscode_development/tree_clipper_addon/_vendor/tree_clipper/export_nodes.py", line 620, in __init__
    _collect_sub_trees(current=root, trees=trees, from_root=from_root)
  File "/home/lars/.config/blender/5.0/extensions/vscode_development/tree_clipper_addon/_vendor/tree_clipper/export_nodes.py", line 536, in _collect_sub_trees
    assert all(current.name != already_in[0].name for already_in in trees)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError

2026-01-18.12-46-00.mp4

[Vollkornaffe]

Unsure what to do about this.

We could import the tree ungrouped, since there's no problem with the interface, unlike with geometry nodes.

We could also not fix this, but rather improve the error message, since there is a workaround for the user: it is to ungroup before attempting to export.