[I] [Bug][Python] Silent config-reconstruction fallback in Action deserialization makes failures very hard to debug [flink-agents]

["alnzng (via GitHub)" <gi...@apache.org>]

alnzng opened a new issue, #920:
URL: https://github.com/apache/flink-agents/issues/920

   ### Search before asking
   
   - [x] I searched in the [issues](https://github.com/apache/flink-agents/issues) and found nothing similar.
   
   ### Description
   
    ### What I was testing
   
     A `ReActAgent` with both `tools` and an `output_schema` (`FlinkSqlJobProfile`). The schema class was importable on the driver but **not on the worker** (a packaging mistake on my side).
   
     ### Symptom
   
     The job failed at runtime pointing at `chat_model_action.py` with a misleading `AttributeError`:
   
     ```
     pemja.core.PythonException: <class 'AttributeError'>: 'list' object has no attribute 'model_dump'
         at .../flink_agents/plan/actions/chat_model_action._save_tool_request_event_context
     (chat_model_action.py:115)
         at .../flink_agents/plan/actions/chat_model_action._handle_tool_calls (chat_model_action.py:237)
         at .../flink_agents/plan/actions/chat_model_action.chat (chat_model_action.py:379)
         at .../flink_agents/plan/actions/chat_model_action._process_chat_request (chat_model_action.py:410)
         at .../flink_agents/plan/actions/chat_model_action.process_chat_request_or_tool_response
     (chat_model_action.py:470)
         at pemja.core.PythonInterpreter.invoke(PythonInterpreter.java:92)
         at org.apache.flink.agents.runtime.operator.ActionExecutionOperator.processActionTaskForKey(ActionExecutionOp
     erator.java:375)
     ```
   
     Nothing here points at the real problem.
   
     ### Actual root cause
     
     `Action.__custom_deserialize` (`plan/actions/action.py`) reconstructs `[module, class, value]` config values
     inside a `try/except` that **silently swallows any failure** and keeps the raw value:
   
     ```python
     for name, value in config.items():
         try:
             module = importlib.import_module(value[0])
             clazz = getattr(module, value[1])
             self["config"][name] = clazz.model_validate(value[2])
         except Exception:          # <-- swallows the real error
             self["config"][name] = value
     ```
   
     My `output_schema` class wasn't importable on the worker → reconstruction raised `ModuleNotFoundError` →
     swallowed → `output_schema` stayed a raw `list` → later `_save_tool_request_event_context` called `.model_dump()` on that list → the misleading `AttributeError` above.
   
     ### What the error *should* have looked like
   
     Making the branch fail fast instead of swallowing gave the true cause and location, at plan-load before any
     record was processed:
   
     ```
     pemja.core.PythonException: <class 'ModuleNotFoundError'>: No module named 'streamingjobprofileagent'
         at <frozen importlib._bootstrap>:1360 (_find_and_load)
         at /export/apps/python/3.12.6/lib/python3.12/importlib/__init__.import_module (__init__.py:90)
         at .../flink_agents/api/agents/types.__custom_deserialize (types.py:65)
         at .../pydantic/main.model_validate (main.py:732)
         at .../flink_agents/plan/actions/action.__custom_deserialize (action.py:94)
         at .../flink_agents/plan/actions/action.__init__ (action.py:107)
         at .../flink_agents/runtime/flink_runner_context.create_flink_runner_context (flink_runner_context.py:773)
         at pemja.core.PythonInterpreter.invoke(PythonInterpreter.java:94)
         at org.apache.flink.agents.runtime.python.utils.PythonActionExecutor.open(PythonActionExecutor.java:108)
         at org.apache.flink.agents.runtime.operator.ActionExecutionOperator.open(ActionExecutionOperator.java:172)
     ```
   
     Real error (`ModuleNotFoundError`), real location (`action.py` / `types.py`), failing at operator `open()` —
     instead of a downstream `AttributeError` in an unrelated module.
   
   
   ### How to reproduce
   
    1. Define a `ReActAgent` with `tools=[...]` and `output_schema=SomeModel`, where `SomeModel` is importable when the plan is built (driver) but **not importable in the worker process**.
     2. Run the agent so the LLM issues a tool call.
     3. The worker crashes with `'list' object has no attribute 'model_dump'` from `chat_model_action.py`, with nothing indicating the real `ModuleNotFoundError` raised during config deserialization in `action.py`.
   
   
   ### Version and environment
   
   - flink-agents: 0.3.0
   - Python: 3.12
   - Flink: 2.2.x, deployed on Kubernetes
   
   
   ### Are you willing to submit a PR?
   
   - [x] I'm willing to submit a PR!


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Re: [I] [Bug][Python] Silent config-reconstruction fallback in Action deserialization makes failures very hard to debug [flink-agents]

["wenjin272 (via GitHub)" <gi...@apache.org>]

wenjin272 closed issue #920: [Bug][Python] Silent config-reconstruction fallback in Action deserialization makes failures very hard to debug
URL: https://github.com/apache/flink-agents/issues/920


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