[BACKPORT 0.2.latest] Support for null value coalescing

.changes/unreleased/Features-20230926-182305.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Add options to protocol for null value coalescing
+time: 2023-09-26T18:23:05.191433-07:00
+custom:
+  Author: QMalcolm
+  Issue: "142"

dbt_semantic_interfaces/implementations/metric.py

@@ -30,6 +30,8 @@ class PydanticMetricInputMeasure(PydanticCustomInputParser, HashableBaseModel):
     name: str
     filter: Optional[PydanticWhereFilter]
     alias: Optional[str]
+    join_to_timespine: bool = False
+    fill_nulls_with: Optional[int] = None
 
     @classmethod
     def _from_yaml_value(cls, input: PydanticParseableValueType) -> PydanticMetricInputMeasure:

dbt_semantic_interfaces/parsing/generated_json_schemas/default_explicit_schema.json

@@ -221,9 +221,15 @@
                         "alias": {
                             "type": "string"
                         },
+                        "fill_nulls_with": {
+                            "type": "integer"
+                        },
                         "filter": {
                             "type": "string"
                         },
+                        "join_to_timespine": {
+                            "type": "boolean"
+                        },
                         "name": {
                             "type": "string"
                         }

dbt_semantic_interfaces/parsing/schemas.py

@@ -46,6 +46,8 @@
                 "name": {"type": "string"},
                 "filter": {"type": "string"},
                 "alias": {"type": "string"},
+                "join_to_timespine": {"type": "boolean"},
+                "fill_nulls_with": {"type": "integer"},
             },
             "additionalProperties": False,
         },

dbt_semantic_interfaces/protocols/metric.py

@@ -43,6 +43,18 @@ def post_aggregation_measure_reference(self) -> MeasureReference:
         """Property accessor to get the MeasureReference with the aliased name, if appropriate."""
         ...
 
+    @property
+    @abstractmethod
+    def join_to_timespine(self) -> bool:
+        """If the measure should be joined to the timespine."""
+        pass
+
+    @property
+    @abstractmethod
+    def fill_nulls_with(self) -> Optional[int]:
+        """What null values should be filled with if set."""
+        pass
+
 
 class MetricTimeWindow(Protocol):
     """Describes the window of time the metric should be accumulated over, e.g., '1 day', '2 weeks', etc."""

tests/parsing/test_metric_parsing.py

@@ -54,6 +54,8 @@ def test_legacy_metric_input_measure_object_parsing() -> None:
             measure:
               name: legacy_measure_from_object
               filter: "{{ dimension('some_bool') }}"
+              join_to_timespine: true
+              fill_nulls_with: 1
         """
     )
     file = YamlConfigFile(filepath="inline_for_test", contents=yaml_contents)
@@ -65,6 +67,8 @@ def test_legacy_metric_input_measure_object_parsing() -> None:
     assert metric.type_params.measure == PydanticMetricInputMeasure(
         name="legacy_measure_from_object",
         filter=PydanticWhereFilter(where_sql_template="""{{ dimension('some_bool') }}"""),
+        join_to_timespine=True,
+        fill_nulls_with=1,
     )