feat: Allow RegisteredMetricHandler to build payloads without a full inline metric definition

PiperOrigin-RevId: 885215504

Author: vertex-sdk-bot

tests/unit/vertexai/genai/replays/test_evaluate.py

@@ -377,6 +377,7 @@ def test_metric_resource_name(client):
     assert evaluation_result.eval_case_results is not None
     assert len(evaluation_result.eval_case_results) > 0
     assert evaluation_result.summary_metrics[0].metric_name == "my_custom_metric"
+    assert evaluation_result.summary_metrics[0].mean_score is not None
 
 
 pytestmark = pytest_helper.setup(

vertexai/_genai/_evals_metric_handlers.py

@@ -965,10 +965,13 @@ def _eval_case_to_agent_data(
             events=events,
         )
 
-    def _build_request_payload(
-        self, eval_case: types.EvalCase, response_index: int
+    @staticmethod
+    def build_evaluation_request_payload(
+        eval_case: types.EvalCase,
+        metric: types.Metric,
+        response_index: int,
     ) -> dict[str, Any]:
-        """Builds the request parameters for evaluate instances request."""
+        """Shared logic to build the EvaluationInstance and AutoraterConfig."""
         response_content = _get_response_from_eval_case(
             eval_case, response_index, self.metric.name
         )
@@ -978,7 +981,7 @@ def _build_request_payload(
                 f"Response content missing for candidate {response_index}."
             )
 
-        if self.metric.name == "tool_use_quality_v1":
+        if metric.name == "tool_use_quality_v1":
             if not _has_tool_call(eval_case.intermediate_events):
                 logger.warning(
                     "Metric 'tool_use_quality_v1' requires tool usage in "
@@ -994,7 +997,7 @@ def _build_request_payload(
 
         extracted_prompt = _get_prompt_from_eval_case(eval_case)
         prompt_instance_data = None
-        if self.metric.name is not None and self.metric.name.startswith("multi_turn"):
+        if metric.name is not None and metric.name.startswith("multi_turn"):
             prompt_contents = []
             if eval_case.conversation_history:
                 for message in eval_case.conversation_history:
@@ -1050,6 +1053,14 @@ def _build_request_payload(
             )
         return request_payload
 
+    def _build_request_payload(
+        self, eval_case: types.EvalCase, response_index: int
+    ) -> dict[str, Any]:
+        """Delegates to the shared static method."""
+        return self.build_evaluation_request_payload(
+            eval_case, self.metric, response_index
+        )
+
     @override
     def get_metric_result(
         self, eval_case: types.EvalCase, response_index: int
@@ -1281,30 +1292,31 @@ def aggregate(
         )
 
 
-class RegisteredMetricHandler(MetricHandler[types.MetricSource]):
+class RegisteredMetricHandler(MetricHandler[Union[types.MetricSource, types.Metric]]):
     """Metric handler for registered metrics."""
 
     def __init__(
         self,
         module: "evals.Evals",
-        metric: Union[types.MetricSource, types.MetricSourceDict],
+        metric: Union[types.MetricSource, types.Metric, types.MetricSourceDict],
     ):
         if isinstance(metric, dict):
             metric = types.MetricSource(**metric)
         super().__init__(module=module, metric=metric)
 
-    # TODO: b/489823454 - Unify _build_request_payload with PredefinedMetricHandler.
     def _build_request_payload(
         self, eval_case: types.EvalCase, response_index: int
     ) -> dict[str, Any]:
-        """Builds request payload for registered metric."""
-        if not self.metric.metric:
-            raise ValueError(
-                "Registered metric must have an underlying metric definition."
-            )
-        return PredefinedMetricHandler(
-            self.module, metric=self.metric.metric
-        )._build_request_payload(eval_case, response_index)
+        """Builds request payload using shared predefined logic."""
+        inline_metric = getattr(self.metric, "metric", None) or (
+            self.metric if isinstance(self.metric, types.Metric) else None
+        )
+
+        metric_for_building = inline_metric or types.Metric(name="registered_metric")
+
+        return PredefinedMetricHandler.build_evaluation_request_payload(
+            eval_case, metric_for_building, response_index
+        )
 
     @property
     def metric_name(self) -> str: