Handle default of None properly for cumulative_type_params (#371)

dbt-core parses YAML differently than DSI. There, the YAML dict for a
metric ends up with if that key is empty. Then when we call
type_params.get(cumulative_type_params, {}), the result is None because
the key does exist in the dict. This results in a key error when we
finally call .get(grain_to_date). Thus, we must set the default value
outside of .get().

Resolves #

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dbt_semantic_interfaces/implementations/metric.py

@@ -209,8 +209,8 @@ def parse_obj(cls, input: Any) -> PydanticMetric:
         data = deepcopy(input)
 
         # Ensure grain_to_date is lowercased
-        type_params = data.get("type_params", {})
-        grain_to_date = type_params.get("cumulative_type_params", {}).get("grain_to_date")
+        type_params = data.get("type_params") or {}
+        grain_to_date = (type_params.get("cumulative_type_params") or {}).get("grain_to_date")
         if isinstance(grain_to_date, str):
             data["type_params"]["cumulative_type_params"]["grain_to_date"] = grain_to_date.lower()
 

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "dbt-semantic-interfaces"
-version = "0.8.2"
+version = "0.8.3"
 description = 'The shared semantic layer definitions that dbt-core and MetricFlow use'
 readme = "README.md"
 requires-python = ">=3.8"