fix: multi-source nodes can be skipped under max_turns

python/packages/autogen-agentchat/src/autogen_agentchat/teams/_group_chat/_graph/_digraph_group_chat.py

@@ -415,7 +415,7 @@ async def update_message_thread(self, messages: Sequence[BaseAgentEvent | BaseCh
 
             if self._activation[target][activation_group] == "all":
                 self._remaining[target][activation_group] -= 1
-                if self._remaining[target][activation_group] == 0:
+                if self._remaining[target][activation_group] >= 0:
                     # If all parents are done, add to the ready queue.
                     self._ready.append(target)
                     # Track which activation group was triggered

python/packages/autogen-agentchat/tests/test_group_chat_graph.py

@@ -532,6 +532,35 @@ async def test_digraph_group_chat_parallel_join_all(runtime: AgentRuntime | None
     assert result.stop_reason is not None
 
 
+@pytest.mark.asyncio
+async def test_digraph_group_chat_multi_source_bypass_max_turns(runtime: AgentRuntime | None) -> None:
+    agent_p = _EchoAgent("P", description="Echo agent P")
+    agent_u = _EchoAgent("U", description="Echo agent U")
+    agent_e = _EchoAgent("E", description="Echo agent E")
+
+    graph = DiGraph(
+        nodes={
+            "P": DiGraphNode(name="P", edges=[DiGraphEdge(target="U"), DiGraphEdge(target="E")]),
+            "U": DiGraphNode(name="U", edges=[DiGraphEdge(target="E")]),
+            "E": DiGraphNode(name="E", edges=[]),
+        }
+    )
+
+    team = GraphFlow(
+        participants=[agent_p, agent_u, agent_e],
+        graph=graph,
+        runtime=runtime,
+        max_turns=2,
+    )
+
+    result: TaskResult = await team.run(task="Start")
+    assert len(result.messages) == 4
+    assert result.messages[0].source == "user"
+    assert result.messages[1].source == "P"
+    assert set(m.source for m in result.messages[2:]) == {"U", "E"}
+    assert result.stop_reason is not None
+
+
 @pytest.mark.asyncio
 async def test_digraph_group_chat_parallel_join_any(runtime: AgentRuntime | None) -> None:
     agent_a = _EchoAgent("A", description="Echo agent A")