[evaluation] feat: Forward input columns that aren't named in evaluator signature to **kwargs (Azure#42893)

* feat: Forward input columns that aren't named in evaluator signature to **kwargs

* tests: Add tests for **kwargs behavior

* test,fix: Check correct row in test

Author: kdestin

sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_legacy/_batch_engine/_engine.py

@@ -344,8 +344,13 @@ def __preprocess_inputs(self, inputs: Mapping[str, Any]) -> Mapping[str, Any]:
 
         func_params = inspect.signature(self._func).parameters
 
-        filtered_params = {key: value for key, value in inputs.items() if key in func_params}
-        return filtered_params
+        has_kwargs = any(p.kind == p.VAR_KEYWORD for p in func_params.values())
+
+        if has_kwargs:
+            return inputs
+        else:
+            filtered_params = {key: value for key, value in inputs.items() if key in func_params}
+            return filtered_params
 
     async def _exec_line_async(
         self,

sdk/evaluation/azure-ai-evaluation/tests/unittests/test_evaluate.py

@@ -975,6 +975,82 @@ def test_name_map_conversion(self):
         assert result[EvaluationRunProperties.NAME_MAP_LENGTH] == -1
         assert len(result) == 1
 
+    def test_evaluate_evaluator_only_kwargs_param(self, evaluate_test_data_jsonl_file):
+        """Validate that an evaluator with only an **kwargs param receives all input in kwargs."""
+
+        def evaluator(**kwargs):
+            return locals()
+
+        result = evaluate(data=evaluate_test_data_jsonl_file, evaluators={"test": evaluator})
+
+        assert len(result["rows"]) == 3
+
+        assert {"query", "response", "ground_truth", "context"}.issubset(result["rows"][0]["outputs.test.kwargs"])
+        assert {"query", "response", "ground_truth", "context"}.issubset(result["rows"][1]["outputs.test.kwargs"])
+        assert {"query", "response", "ground_truth", "context"}.issubset(result["rows"][2]["outputs.test.kwargs"])
+
+    def test_evaluate_evaluator_kwargs_param(self, evaluate_test_data_jsonl_file):
+        """Validate that an evaluator with named parameters and **kwargs obeys python function call semantics."""
+
+        def evaluator(query, response, *, bar=None, **kwargs):
+            return locals()
+
+        result = evaluate(data=evaluate_test_data_jsonl_file, evaluators={"test": evaluator})
+
+        assert len(result["rows"]) == 3
+
+        row1_kwargs = result["rows"][0]["outputs.test.kwargs"]
+        row2_kwargs = result["rows"][1]["outputs.test.kwargs"]
+        row3_kwargs = result["rows"][2]["outputs.test.kwargs"]
+
+        assert {"ground_truth", "context"}.issubset(row1_kwargs), "Unnamed parameters should be in kwargs"
+        assert {"query", "response", "bar"}.isdisjoint(row1_kwargs), "Named parameters should not be in kwargs"
+
+        assert {"ground_truth", "context"}.issubset(row2_kwargs), "Unnamed parameters should be in kwargs"
+        assert {"query", "response", "bar"}.isdisjoint(row2_kwargs), "Named parameters should not be in kwargs"
+
+        assert {"ground_truth", "context"}.issubset(row3_kwargs), "Unnamed parameters should be in kwargs"
+        assert {"query", "response", "bar"}.isdisjoint(row3_kwargs), "Named parameters should not be in kwargs"
+
+    def test_evaluate_evaluator_kwargs_param_column_mapping(self, evaluate_test_data_jsonl_file):
+        """Validate that an evaluator with kwargs can receive column mapped values."""
+
+        def evaluator(query, response, *, bar=None, **kwargs):
+            return locals()
+
+        result = evaluate(
+            data=evaluate_test_data_jsonl_file,
+            evaluators={"test": evaluator},
+            evaluator_config={
+                "default": {
+                    "column_mapping": {
+                        "query": "${data.query}",
+                        "response": "${data.response}",
+                        "foo": "${data.context}",
+                        "bar": "${data.ground_truth}",
+                    }
+                }
+            },
+        )
+
+        assert len(result["rows"]) == 3
+
+        row1_kwargs = result["rows"][0]["outputs.test.kwargs"]
+        row2_kwargs = result["rows"][1]["outputs.test.kwargs"]
+        row3_kwargs = result["rows"][2]["outputs.test.kwargs"]
+
+        assert {"ground_truth", "context"}.issubset(row1_kwargs), "Unnamed parameters should be in kwargs"
+        assert "foo" in row1_kwargs, "Making a column mapping to an unnamed parameter should appear in kwargs"
+        assert {"query", "response", "bar"}.isdisjoint(row1_kwargs), "Named parameters should not be in kwargs"
+
+        assert {"ground_truth", "context"}.issubset(row2_kwargs), "Unnamed parameters should be in kwargs"
+        assert "foo" in row2_kwargs, "Making a column mapping to an unnamed parameter should appear in kwargs"
+        assert {"query", "response", "bar"}.isdisjoint(row2_kwargs), "Named parameters should not be in kwargs"
+
+        assert {"ground_truth", "context"}.issubset(row3_kwargs), "Unnamed parameters should be in kwargs"
+        assert "foo" in row3_kwargs, "Making a column mapping to an unnamed parameter should appear in kwargs"
+        assert {"query", "response", "bar"}.isdisjoint(row3_kwargs), "Named parameters should not be in kwargs"
+
 
 @pytest.mark.unittest
 class TestTagsInLoggingFunctions: