From 9da9dab1d112d57aed190f33c7a0de779e597167 Mon Sep 17 00:00:00 2001
From: Paul Yang <github@ardorful.com>
Date: Mon, 18 Nov 2024 11:51:57 -0800
Subject: [PATCH] Handle metric case for `ObjectBuilderNamingScheme`.

---
 .../naming/object_builder_str.py              | 20 +++++++++----------
 .../test_object_builder_naming_scheme.py      |  3 +++
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/metricflow-semantics/metricflow_semantics/naming/object_builder_str.py b/metricflow-semantics/metricflow_semantics/naming/object_builder_str.py
index 3810bf34ed..126f100d4d 100644
--- a/metricflow-semantics/metricflow_semantics/naming/object_builder_str.py
+++ b/metricflow-semantics/metricflow_semantics/naming/object_builder_str.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import logging
 from typing import Optional, Sequence
 
 from dbt_semantic_interfaces.call_parameter_sets import (
@@ -13,9 +14,12 @@
 from dbt_semantic_interfaces.type_enums.date_part import DatePart
 from typing_extensions import override
 
+from metricflow_semantics.mf_logging.lazy_formattable import LazyFormat
 from metricflow_semantics.specs.instance_spec import InstanceSpec
 from metricflow_semantics.specs.spec_set import InstanceSpecSet, InstanceSpecSetTransform, group_spec_by_type
 
+logger = logging.getLogger(__name__)
+
 
 class ObjectBuilderNameConverter:
     """Methods for converting classes related to the object-builder naming scheme to strings.
@@ -85,14 +89,6 @@ class _ObjectBuilderNameTransform(InstanceSpecSetTransform[Sequence[str]]):
 
         @override
         def transform(self, spec_set: InstanceSpecSet) -> Sequence[str]:
-            assert (
-                len(spec_set.entity_specs)
-                + len(spec_set.dimension_specs)
-                + len(spec_set.time_dimension_specs)
-                + len(spec_set.group_by_metric_specs)
-                == 1
-            )
-
             names_to_return = []
 
             for entity_spec in spec_set.entity_specs:
@@ -138,11 +134,13 @@ def transform(self, spec_set: InstanceSpecSet) -> Sequence[str]:
             return names_to_return
 
     @staticmethod
-    def input_str_from_spec(instance_spec: InstanceSpec) -> str:  # noqa: D102
+    def input_str_from_spec(instance_spec: InstanceSpec) -> Optional[str]:  # noqa: D102
         names = ObjectBuilderNameConverter._ObjectBuilderNameTransform().transform(group_spec_by_type(instance_spec))
 
-        if len(names) != 1:
-            raise RuntimeError(f"Did not get exactly 1 name from {instance_spec}. Got {names}")
+        if len(names) == 0:
+            return None
+        elif len(names) > 1:
+            raise RuntimeError(str(LazyFormat("Expected at most one name", instance_spec=instance_spec, names=names)))
 
         return names[0]
 
diff --git a/metricflow-semantics/tests_metricflow_semantics/naming/test_object_builder_naming_scheme.py b/metricflow-semantics/tests_metricflow_semantics/naming/test_object_builder_naming_scheme.py
index 1b8a058a32..ed62631a17 100644
--- a/metricflow-semantics/tests_metricflow_semantics/naming/test_object_builder_naming_scheme.py
+++ b/metricflow-semantics/tests_metricflow_semantics/naming/test_object_builder_naming_scheme.py
@@ -12,6 +12,7 @@
 from metricflow_semantics.specs.entity_spec import EntitySpec
 from metricflow_semantics.specs.group_by_metric_spec import GroupByMetricSpec
 from metricflow_semantics.specs.instance_spec import LinkableInstanceSpec
+from metricflow_semantics.specs.metric_spec import MetricSpec
 from metricflow_semantics.specs.time_dimension_spec import TimeDimensionSpec
 from metricflow_semantics.test_helpers.metric_time_dimension import MTD_SPEC_MONTH, MTD_SPEC_WEEK, MTD_SPEC_YEAR
 from metricflow_semantics.time.granularity import ExpandedTimeGranularity
@@ -63,6 +64,8 @@ def test_input_str(object_builder_naming_scheme: ObjectBuilderNamingScheme) -> N
         == "Metric('bookings', group_by=['listing'])"
     )
 
+    assert object_builder_naming_scheme.input_str(MetricSpec("bookings")) is None
+
 
 def test_input_follows_scheme(object_builder_naming_scheme: ObjectBuilderNamingScheme) -> None:  # noqa: D103
     assert object_builder_naming_scheme.input_str_follows_scheme(