fix(agentchat): dispatch CodeExecutorAgent reflection via self.__class__ (#7205)

[GopalGB]

Closes #7205. Mirrors the AssistantAgent polymorphism fix from #5953.

Repro

CodeExecutorAgent.on_messages_stream calls _reflect_on_code_block_results_flow through the concrete CodeExecutorAgent. reference (_code_executor_agent.py:667):

async for reflection_response in CodeExecutorAgent._reflect_on_code_block_results_flow(
    ...
):

_reflect_on_code_block_results_flow is a @classmethod, so calling through the concrete class static-binds to the parent's implementation regardless of self's actual class. A subclass that overrides the reflection flow:

class MyAgent(CodeExecutorAgent):
    @classmethod
    async def _reflect_on_code_block_results_flow(cls, ...):
        # custom behavior
        ...

is silently ignored. The override never fires, the parent runs instead, no exception is raised, and the bug is invisible. The reporter found this exact pattern was previously fixed for AssistantAgent in #5953 — this is the unfixed twin in CodeExecutorAgent.

Fix

Route the call through self.__class__:

async for reflection_response in self.__class__._reflect_on_code_block_results_flow(
    ...
):

Because _reflect_on_code_block_results_flow is a @classmethod, dispatching through self.__class__ preserves the existing cls semantics without any signature change to the classmethod itself. Two-line change plus a docstring comment pointing at #7205 and #5953.

Test

test_subclass_overrides_reflect_on_code_block_results_flow defines a CustomCodeExecutorAgent(CodeExecutorAgent) that overrides _reflect_on_code_block_results_flow to yield a sentinel Response. After running on_messages_stream against a replay model client, the test asserts the final Response.chat_message.content equals the sentinel.

Before the fix:

• Parent reflection runs against the replay client and yields its second canned response (TERMINATE).
• Sentinel is never observed.
• Test FAILS.

After the fix:

• Subclass override fires.
• Sentinel is the final response.
• Test PASSES.

Verification:

# With fix
$ python -m pytest tests/test_code_executor_agent.py::test_subclass_overrides_reflect_on_code_block_results_flow
1 passed in 2.60s

# Reverting only the source change
$ git stash push python/packages/autogen-agentchat/src/autogen_agentchat/agents/_code_executor_agent.py
$ python -m pytest tests/test_code_executor_agent.py::test_subclass_overrides_reflect_on_code_block_results_flow
1 failed in 0.62s

Full test_code_executor_agent.py suite: 27 passed.

🤖 Generated with Claude Code

[GopalGB]

Friendly ping — fix(agentchat): dispatch CodeExecutorAgent reflection via self.__class__ (#7205). CI green, CLA signed. cc maintainers.