feat(gui): Add link deletion and DAG cycle validation to Visual DAG

src/gui_2.py

@@ -572,6 +572,13 @@ class App:
       self._handle_mma_respond(approved=False, abort=True)
       imgui.close_current_popup()
     imgui.end_popup()
+   # Cycle Detected Popup
+   if imgui.begin_popup_modal("Cycle Detected!", None, imgui.WindowFlags_.always_auto_resize)[0]:
+    imgui.text_colored(imgui.ImVec4(1, 0.3, 0.3, 1), "The dependency graph contains a cycle!")
+    imgui.text("Please remove the circular dependency.")
+    if imgui.button("OK"):
+     imgui.close_current_popup()
+    imgui.end_popup()
    if self.show_script_output:
     if self._trigger_script_blink:
      self._trigger_script_blink = False
@@ -1583,6 +1590,28 @@ class App:
     tid = str(t.get('id', '??'))
     for dep in t.get('depends_on', []):
      ed.link(abs(hash(dep + "_" + tid)), abs(hash(dep + "_out")), abs(hash(tid + "_in")))
+   # Handle link deletion
+   if ed.begin_delete():
+    deleted = ed.get_deleted_link()
+    if deleted:
+     link_id = deleted[0]
+     for t in self.active_tickets:
+      tid = str(t.get('id', ''))
+      for d in t.get('depends_on', []):
+       if abs(hash(d + "_" + tid)) == link_id:
+        t['depends_on'] = [dep for dep in t['depends_on'] if dep != d]
+        self._push_mma_state_update()
+        break
+    ed.end_delete()
+   # Validate DAG after any changes
+   try:
+    from src.dag_engine import TrackDAG
+    ticket_dicts = [{'id': str(t.get('id', '')), 'depends_on': t.get('depends_on', [])} for t in self.active_tickets]
+    temp_dag = TrackDAG(ticket_dicts)
+    if temp_dag.has_cycle():
+     imgui.open_popup("Cycle Detected!")
+   except Exception:
+    pass
    ed.end()
    ed.set_current_editor(None)
    # 5. Add Ticket Form