Remove connected items from the diagram

E.g. when a class is removed, also remove the connected associations and
dependencies.

gaphor/core/modeling/presentation.py

@@ -102,7 +102,13 @@ class Presentation(Matrices, Element, Generic[S]):
             self.parent.matrix_i2c.remove_handler(self._on_matrix_changed)
 
         if diagram := self._original_diagram:
+            connecting_items = list(
+                cinfo.item
+                for cinfo in diagram.connections.get_connections(connected=self)
+            )
             diagram.connections.remove_connections_to_item(self)
+            for item in connecting_items:
+                item.unlink()
             self._original_diagram = None
             super().inner_unlink(UnlinkEvent(self, diagram=diagram))
 

gaphor/diagram/general/tests/test_comment.py

@@ -182,7 +182,8 @@ def test_commentline_element_unlink(create, diagram):
 
     assert clazz not in diagram.ownedPresentation
     assert not clazz.diagram
-    assert line.diagram
+    assert line not in diagram.ownedPresentation
+    assert not line.diagram
     assert not comment.subject.annotatedElement
     assert len(clazz_subject.comment) == 0
 

gaphor/diagram/tests/test_presentation.py

@@ -1,5 +1,7 @@
 from gaphor import UML
 from gaphor.diagram.presentation import ElementPresentation, LinePresentation
+from gaphor.diagram.tests.fixtures import connect
+from gaphor.UML import diagramitems
 
 
 class DummyVisualComponent:
@@ -133,3 +135,18 @@ def test_line_loading(element_factory, diagram):
     assert tuple(p.handles()[0].pos) == (1.0, 2.0)
     assert tuple(p.handles()[1].pos) == (3.0, 4.0)
     assert p.subject is subject
+
+
+def test_remove_connected_items_on_unlink(create, diagram):
+    class_a_item = create(diagramitems.ClassItem, UML.Class)
+    class_b_item = create(diagramitems.ClassItem, UML.Class)
+    association_item = create(diagramitems.AssociationItem)
+
+    connect(association_item, association_item.head, class_a_item)
+    connect(association_item, association_item.tail, class_b_item)
+
+    class_a_item.subject.unlink()
+
+    assert class_a_item not in diagram.ownedPresentation
+    assert association_item not in diagram.ownedPresentation
+    assert class_b_item in diagram.ownedPresentation

tests/test_undo.py

@@ -42,6 +42,12 @@ def undo_manager(session):
 def test_class_association_undo_redo(event_manager, element_factory, undo_manager):
     diagram, ci1, ci2, a = set_up_class_and_association(event_manager, element_factory)
 
+    def get_connected(handle):
+        """Get item connected to line via handle."""
+        if cinfo := diagram.connections.get_connection(handle):
+            return cinfo.connected
+        return None
+
     undo_manager.clear_undo_stack()
     assert not undo_manager.can_undo()
 
@@ -50,22 +56,14 @@ def test_class_association_undo_redo(event_manager, element_factory, undo_manage
 
     assert undo_manager.can_undo()
 
-    def get_connected(handle):
-        """Get item connected to line via handle."""
-        if cinfo := diagram.connections.get_connection(handle):
-            return cinfo.connected
-        return None
-
-    assert ci1 == get_connected(a.head)
-    assert None is get_connected(a.tail)
-
     for i in range(3):
-        assert 9 == len(diagram.connections.solver.constraints)
+        assert 8 == len(diagram.connections.solver.constraints)
 
         undo_manager.undo_transaction()
 
         assert 18 == len(diagram.connections.solver.constraints)
 
+        a = next(element_factory.select(AssociationItem))
         assert ci1 == get_connected(a.head)
         assert ci2.id == get_connected(a.tail).id