chore: address subtree moving within same parent

docling_core/types/doc/document.py

@@ -3486,16 +3486,16 @@ def _move_subtree(self, *, old_subroot: NodeItem, new_subroot: NodeItem, pos: in
         if old_subroot.parent is None:
             raise ValueError("Can not move the root")
 
+        # unlink old subroot from its previous parent
+        previous_parent: NodeItem = old_subroot.parent.resolve(doc=self)
+        previous_parent.children.remove(old_subroot.get_ref())
+
         # link new subroot => old subroot
         if pos is not None:
             new_subroot.children.insert(pos, old_subroot.get_ref())
         else:
             new_subroot.children.append(old_subroot.get_ref())
 
-        # unlink old subroot from its previous parent
-        previous_parent: NodeItem = old_subroot.parent.resolve(doc=self)
-        previous_parent.children.remove(old_subroot.get_ref())
-
         # link old subroot => new subroot
         old_subroot.parent = new_subroot.get_ref()
 

test/test_docling_doc.py

@@ -1549,6 +1549,14 @@ def test_misplaced_list_items():
         exp_doc = DoclingDocument.load_from_yaml(exp_file)
         assert doc == exp_doc
 
+def test_moving_within_same_parent():
+    doc = DoclingDocument(name="")
+    doc.add_text(label=DocItemLabel.TEXT, text="bar")
+    foo = doc.add_text(label=DocItemLabel.TEXT, text="foo")
+    assert foo.parent is not None
+    doc._move_subtree(old_subroot=foo, new_subroot=foo.parent.resolve(doc), pos=0)
+    assert [it.text for it, _ in doc.iterate_items() if isinstance(it, TextItem)] == ["foo", "bar"]
+
 
 def test_export_with_precision():
     doc = DoclingDocument.load_from_yaml(filename="test/data/doc/dummy_doc_2.yaml")