This is an automated email from the ASF dual-hosted git repository.
wenjin272 pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/flink-agents.git
The following commit(s) were added to refs/heads/main by this push:
new 63e67226 [python] warn when an action declares a return value (#835)
63e67226 is described below
commit 63e67226612130b9f74ccddf8d437825fefdbd4c
Author: vishnu prakash <[email protected]>
AuthorDate: Mon Aug 3 08:54:06 2026 +0530
[python] warn when an action declares a return value (#835)
---
python/flink_agents/plan/actions/action.py | 2 +-
python/flink_agents/plan/function.py | 26 ++++++++++++++++
python/flink_agents/plan/tests/test_action.py | 36 +++++++++++++++++++++++
python/flink_agents/plan/tests/test_agent_plan.py | 26 ++++++++++++++++
4 files changed, 89 insertions(+), 1 deletion(-)
diff --git a/python/flink_agents/plan/actions/action.py
b/python/flink_agents/plan/actions/action.py
index 9d57ae7c..efdf4855 100644
--- a/python/flink_agents/plan/actions/action.py
+++ b/python/flink_agents/plan/actions/action.py
@@ -51,7 +51,6 @@ class Action(BaseModel):
model_config = ConfigDict(arbitrary_types_allowed=True)
name: str
- # TODO: Raise a warning when the action has a return value, as it will be
ignored.
exec: PythonFunction | JavaFunction
trigger_conditions: List[str]
config: Dict[str, Any] | None = None
@@ -124,3 +123,4 @@ class Action(BaseModel):
)
# TODO: Update expected signature after import State and Context.
self.exec.check_signature(Event, RunnerContext)
+ self.exec.warn_if_returns_value(self.name)
diff --git a/python/flink_agents/plan/function.py
b/python/flink_agents/plan/function.py
index 28bc5089..7988084a 100644
--- a/python/flink_agents/plan/function.py
+++ b/python/flink_agents/plan/function.py
@@ -108,6 +108,14 @@ class Function(BaseModel, ABC):
def check_signature(self, *args: Tuple[Any, ...]) -> None:
"""Check function signature is legal or not."""
+ def warn_if_returns_value(self, action_name: str) -> None:
+ """Warn if this function declares a non-``None`` return annotation.
+
+ Action return values are discarded by the framework, so declaring a
+ return type is almost always a mistake. Only Python callables can be
+ introspected, so non-Python function types treat this as a no-op.
+ """
+
@abstractmethod
def __call__(self, *args: Tuple[Any, ...], **kwargs: Dict[str, Any]) ->
Any:
"""Execute function."""
@@ -191,6 +199,24 @@ class PythonFunction(Function):
except TypeError as e:
raise TypeError(err_msg) from e
+ def warn_if_returns_value(self, action_name: str) -> None:
+ """Warn that an action's return value is ignored by the framework.
+
+ Actions communicate by sending events via ``ctx.send_event(...)``; any
+ value they return is discarded. A non-``None`` return annotation is
+ almost always a mistake, so surface it when the plan is built. The
+ stringized ``"None"`` is accepted for modules that opt into
+ ``from __future__ import annotations``.
+ """
+ return_annotation =
inspect.signature(self.__get_func()).return_annotation
+ if return_annotation not in (inspect.Signature.empty, None,
type(None), "None"):
+ logger.warning(
+ f"Action '{action_name}' declares return type "
+ f"'{return_annotation}', but action return values are ignored
by "
+ f"the framework. Actions should send events via "
+ f"ctx.send_event(...) and return None."
+ )
+
def __call__(self, *args: Tuple[Any, ...], **kwargs: Dict[str, Any]) ->
Any:
"""Execute the stored function with provided arguments.
diff --git a/python/flink_agents/plan/tests/test_action.py
b/python/flink_agents/plan/tests/test_action.py
index 08f0d5dd..da097d04 100644
--- a/python/flink_agents/plan/tests/test_action.py
+++ b/python/flink_agents/plan/tests/test_action.py
@@ -16,6 +16,7 @@
# limitations under the License.
#################################################################################
import json
+import logging
from pathlib import Path
import pytest
@@ -36,6 +37,10 @@ def illegal_signature(value: int, ctx: RunnerContext) ->
None:
pass
+def returns_value(event: Event, ctx: RunnerContext) -> str:
+ return "ignored by the framework"
+
+
def test_action_signature_legal() -> None:
Action(
name="legal",
@@ -53,6 +58,37 @@ def test_action_signature_illegal() -> None:
)
+def test_action_warns_when_returns_value(
+ caplog: pytest.LogCaptureFixture,
+) -> None:
+ with caplog.at_level(logging.WARNING):
+ Action(
+ name="returns_value",
+ exec=PythonFunction.from_callable(returns_value),
+ trigger_conditions=[InputEvent.EVENT_TYPE],
+ )
+ assert any(
+ "returns_value" in record.getMessage()
+ and "ignored" in record.getMessage().lower()
+ for record in caplog.records
+ )
+
+
+def test_action_no_warning_when_returns_none(
+ caplog: pytest.LogCaptureFixture,
+) -> None:
+ with caplog.at_level(logging.WARNING):
+ Action(
+ name="legal",
+ exec=PythonFunction.from_callable(legal_signature),
+ trigger_conditions=[InputEvent.EVENT_TYPE],
+ )
+ assert not any(
+ "ignored by the framework" in record.getMessage()
+ for record in caplog.records
+ )
+
+
@pytest.fixture(scope="module")
def action() -> Action:
func = PythonFunction.from_callable(legal_signature)
diff --git a/python/flink_agents/plan/tests/test_agent_plan.py
b/python/flink_agents/plan/tests/test_agent_plan.py
index 04fdb6c7..c92e36b0 100644
--- a/python/flink_agents/plan/tests/test_agent_plan.py
+++ b/python/flink_agents/plan/tests/test_agent_plan.py
@@ -16,6 +16,7 @@
# limitations under the License.
#################################################################################
import json
+import logging
from pathlib import Path
from typing import Any, ClassVar, Dict, List, Sequence
@@ -565,6 +566,31 @@ def test_add_action_and_resource_to_agent() -> None:
assert actual == expected
+def _returns_value_action(event: Event, ctx: RunnerContext) -> str:
+ return "ignored by the framework"
+
+
+def test_warns_for_returning_action_added_via_add_action(
+ caplog: pytest.LogCaptureFixture,
+) -> None:
+ """Actions registered imperatively via add_action are also checked, since
+ the warning now lives in Action.__init__ rather than a single collection
path.
+ """
+ agent = Agent()
+ agent.add_action(
+ name="returns_value",
+ trigger_conditions=[InputEvent.EVENT_TYPE],
+ func=_returns_value_action,
+ )
+ with caplog.at_level(logging.WARNING):
+ AgentPlan.from_agent(agent, AgentConfiguration())
+ assert any(
+ "returns_value" in record.getMessage()
+ and "ignored" in record.getMessage().lower()
+ for record in caplog.records
+ )
+
+
# ── String identifier tests ──────────────────────────────────────────────
