Exercise LangChain server demo in e2e

Constraint: GitHub e2e ignores tests/e2e/integration and filters node ids containing invoke.

Rejected: Use real ModelService, sandbox, or MemoryCollection resources | CI should verify SDK wiring without external service flakiness.

Confidence: high

Scope-risk: narrow

Directive: Keep this demo case in a GitHub e2e-collected path and avoid excluded node-id terms.

Tested: uv run --python 3.10 --all-extras pytest tests/unittests/integration/test_langchain_convert.py::TestConvertAstreamEventsFormat::test_on_chain_stream_model_command_update_text tests/e2e/test_langchain_server_demo.py -v --tb=short

Tested: uv run --python 3.10 --all-extras pytest tests/e2e/ --collect-only -q --ignore=tests/e2e/integration --ignore=tests/e2e/test_agent_ruintime.py --ignore=tests/e2e/test_workspace_id.py --ignore=tests/e2e/test_sandbox_browser.py --ignore=tests/e2e/test_sandbox_code_interpreter.py -k 'not (invoke or with_credential or model_proxy or process_get or delete_sandbox or delete_nonexistent_sandbox or connect_nonexistent or connect_sandbox_async or sandbox_lifecycle or connect_with_wrong_template or template_validation_code_interpreter_network or playwright or browser_recordings or aio_combined_workflow or browser_code_file_integration or aio_lifecycle)'

Tested: uv run --python 3.10 --all-extras make mypy-check

Tested: uv run --python 3.10 --all-extras make coverage

Change-Id: I1769d00572e34d1516fca6e3b4add452122d3c83
Not-tested: Real cloud sandbox and MemoryCollection resources are mocked in the e2e case.
Signed-off-by: congxiao.wxx <congxiao.wxx@alibaba-inc.com>

Author: congxiao-wxx

agentrun/integration/langgraph/agent_converter.py

@@ -730,9 +730,19 @@ def _convert_astream_events_event(
             and not self.has_on_chat_model_stream
         ):
             chunk_data = data.get("chunk", {})
+            messages = []
             if isinstance(chunk_data, dict):
                 messages = chunk_data.get("messages", [])
+            elif isinstance(chunk_data, list):
+                for item in chunk_data:
+                    update = getattr(item, "update", None)
+                    if not isinstance(update, dict):
+                        continue
+                    item_messages = update.get("messages", [])
+                    if isinstance(item_messages, list):
+                        messages.extend(item_messages)
 
+            if isinstance(messages, list):
                 for msg in messages:
                     content = AgentRunConverter._get_message_content(msg)
                     if content: