Fix: Handle case where partition_by is explicitly passed in as None to dbt ModelConfig

Author: crericha

sqlmesh/dbt/model.py

@@ -154,7 +154,11 @@ def _validate_sql(cls, v: t.Union[str, SqlStr]) -> SqlStr:
 
     @field_validator("partition_by", mode="before")
     @classmethod
-    def _validate_partition_by(cls, v: t.Any) -> t.Union[t.List[str], t.Dict[str, t.Any]]:
+    def _validate_partition_by(
+        cls, v: t.Any
+    ) -> t.Optional[t.Union[t.List[str], t.Dict[str, t.Any]]]:
+        if v is None:
+            return None
         if isinstance(v, str):
             return [v]
         if isinstance(v, list):

tests/dbt/test_transformation.py

@@ -1329,6 +1329,23 @@ def test_partition_by(sushi_test_project: Project):
     assert model_config.to_sqlmesh(context).partitioned_by == [exp.to_column("ds", quoted=True)]
 
 
+@pytest.mark.xdist_group("dbt_manifest")
+def test_partition_by_none(sushi_test_project: Project):
+    context = sushi_test_project.context
+    context.target = BigQueryConfig(name="production", database="main", schema="sushi")
+    model_config = ModelConfig(
+        name="model",
+        alias="model",
+        schema="test",
+        package_name="package",
+        materialized="table",
+        unique_key="ds",
+        partition_by=None,
+        sql="""SELECT 1 AS one, ds FROM foo""",
+    )
+    assert model_config.partition_by is None
+
+
 @pytest.mark.xdist_group("dbt_manifest")
 def test_relation_info_to_relation():
     assert _relation_info_to_relation(