bugs: handle merging of top level nodes

Resolves: #125
Resolves: #167
Signed-off-by: Arthur Zamarin <arthurzam@gentoo.org>

Author: arthurzam

src/pkgdev/scripts/pkgdev_bugs.py

@@ -437,6 +437,7 @@ def merge_cycles(self):
             assert starting_node in self.nodes
             while cycle := self._find_cycles(tuple(self.nodes), [starting_node]):
                 self.out.write("Found cycle: ", " -> ".join(str(n) for n in cycle))
+                start_nodes.difference_update(cycle)
                 new_node = self.merge_nodes(cycle)
                 if starting_node not in self.nodes:
                     starting_node = new_node