fix(middleware): fallback to configurable thread_id in thread data middleware (#1237)

Co-authored-by: Exploreunive <Exploreunive@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/tests/test_thread_data_middleware.py

@@ -0,0 +1,54 @@
+import pytest
+from langgraph.runtime import Runtime
+
+from deerflow.agents.middlewares.thread_data_middleware import ThreadDataMiddleware
+
+
+class TestThreadDataMiddleware:
+    def test_before_agent_returns_paths_when_thread_id_present_in_context(self, tmp_path):
+        middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
+
+        result = middleware.before_agent(state={}, runtime=Runtime(context={"thread_id": "thread-123"}))
+
+        assert result is not None
+        assert result["thread_data"]["workspace_path"].endswith("threads/thread-123/user-data/workspace")
+        assert result["thread_data"]["uploads_path"].endswith("threads/thread-123/user-data/uploads")
+        assert result["thread_data"]["outputs_path"].endswith("threads/thread-123/user-data/outputs")
+
+    def test_before_agent_uses_thread_id_from_configurable_when_context_is_none(self, tmp_path, monkeypatch):
+        middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
+        runtime = Runtime(context=None)
+        monkeypatch.setattr(
+            "deerflow.agents.middlewares.thread_data_middleware.get_config",
+            lambda: {"configurable": {"thread_id": "thread-from-config"}},
+        )
+
+        result = middleware.before_agent(state={}, runtime=runtime)
+
+        assert result is not None
+        assert result["thread_data"]["workspace_path"].endswith("threads/thread-from-config/user-data/workspace")
+        assert runtime.context is None
+
+    def test_before_agent_uses_thread_id_from_configurable_when_context_missing_thread_id(self, tmp_path, monkeypatch):
+        middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
+        runtime = Runtime(context={})
+        monkeypatch.setattr(
+            "deerflow.agents.middlewares.thread_data_middleware.get_config",
+            lambda: {"configurable": {"thread_id": "thread-from-config"}},
+        )
+
+        result = middleware.before_agent(state={}, runtime=runtime)
+
+        assert result is not None
+        assert result["thread_data"]["uploads_path"].endswith("threads/thread-from-config/user-data/uploads")
+        assert runtime.context == {}
+
+    def test_before_agent_raises_clear_error_when_thread_id_missing_everywhere(self, tmp_path, monkeypatch):
+        middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
+        monkeypatch.setattr(
+            "deerflow.agents.middlewares.thread_data_middleware.get_config",
+            lambda: {"configurable": {}},
+        )
+
+        with pytest.raises(ValueError, match="Thread ID is required in runtime context or config.configurable"):
+            middleware.before_agent(state={}, runtime=Runtime(context=None))