FIX: Add error message if extension is started with an empty HFSS 3D Layout design

doc/changelog.d/6822.fixed.md

@@ -0,0 +1 @@
+Add error message if extension is started with an empty HFSS 3D Layout design

src/ansys/aedt/core/extensions/hfss3dlayout/cutout.py

@@ -209,6 +209,9 @@ def execute_cutout(self):
     def __load_objects_net(self):
         """Load objects by net from the EDB modeler."""
         res = defaultdict(list)
+        if not self.aedt_application.modeler.edb:
+            self.release_desktop()
+            raise AEDTRuntimeError("Extension cannot be used with an empty HFSS 3D Layout design.")
         for net, net_objs in self.aedt_application.modeler.edb.modeler.primitives_by_net.items():
             res[net].extend(obj.aedt_name for obj in net_objs)
         for net_obj in self.aedt_application.modeler.edb.padstacks.instances.values():

tests/unit/extensions/test_cutout.py

@@ -35,6 +35,7 @@
 from ansys.aedt.core.extensions.hfss3dlayout.cutout import WAITING_FOR_SELECTION
 from ansys.aedt.core.extensions.hfss3dlayout.cutout import CutoutData
 from ansys.aedt.core.extensions.hfss3dlayout.cutout import CutoutExtension
+from ansys.aedt.core.internal.errors import AEDTRuntimeError
 
 MOCK_LINE_0 = "line__0"
 MOCK_LINE_1 = "line__1"
@@ -79,6 +80,14 @@ def mock_hfss_3d_layout_with_primitives(request, mock_hfss_3d_layout_app):
     yield mock_hfss_3d_layout_app
 
 
+def test_cutout_extension_empty_design(mock_hfss_3d_layout_app):
+    """Test that CutoutExtension raises an error if launched with an empty design."""
+    mock_hfss_3d_layout_app.modeler.edb = None
+
+    with pytest.raises(AEDTRuntimeError, match="Extension cannot be used with an empty HFSS 3D Layout design."):
+        CutoutExtension(withdraw=True)
+
+
 def test_cutout_extension_default(mock_hfss_3d_layout_with_primitives):
     """Test instantiation of CutoutExtension with default parameters."""
     EXPECTED_OBJS_NET = {