Fix: Warn instead of fail on incompatible incremental strategy for dbt models with a unique key (#5166)

Author: izeigerman

sqlmesh/dbt/model.py

@@ -293,10 +293,11 @@ def model_kind(self, context: DbtContext) -> ModelKind:
                     self.incremental_strategy
                     and strategy not in INCREMENTAL_BY_UNIQUE_KEY_STRATEGIES
                 ):
-                    raise ConfigError(
-                        f"{self.canonical_name(context)}: SQLMesh incremental by unique key strategy is not compatible with '{strategy}'"
-                        f" incremental strategy. Supported strategies include {collection_to_str(INCREMENTAL_BY_UNIQUE_KEY_STRATEGIES)}."
+                    get_console().log_warning(
+                        f"Unique key is not compatible with '{strategy}' incremental strategy in model '{self.canonical_name(context)}'. "
+                        f"Supported strategies include {collection_to_str(INCREMENTAL_BY_UNIQUE_KEY_STRATEGIES)}. Falling back to 'merge' strategy."
                     )
+                    strategy = "merge"
 
                 if self.incremental_predicates:
                     dialect = self.dialect(context)

tests/dbt/test_transformation.py

@@ -238,6 +238,16 @@ def test_model_kind():
         auto_restatement_cron="0 0 * * *",
     )
 
+    # Test incompatibile incremental strategies
+    for incremental_strategy in ("delete+insert", "insert_overwrite", "append"):
+        assert ModelConfig(
+            materialized=Materialization.INCREMENTAL,
+            unique_key=["bar"],
+            incremental_strategy=incremental_strategy,
+        ).model_kind(context) == IncrementalByUniqueKeyKind(
+            unique_key=["bar"], dialect="duckdb", forward_only=True, disable_restatement=False
+        )
+
     assert ModelConfig(
         materialized=Materialization.INCREMENTAL, time_column="foo", incremental_strategy="merge"
     ).model_kind(context) == IncrementalByTimeRangeKind(
@@ -372,25 +382,6 @@ def test_model_kind():
         == ManagedKind()
     )
 
-    with pytest.raises(ConfigError):
-        ModelConfig(
-            materialized=Materialization.INCREMENTAL,
-            unique_key=["bar"],
-            incremental_strategy="delete+insert",
-        ).model_kind(context)
-    with pytest.raises(ConfigError):
-        ModelConfig(
-            materialized=Materialization.INCREMENTAL,
-            unique_key=["bar"],
-            incremental_strategy="insert_overwrite",
-        ).model_kind(context)
-    with pytest.raises(ConfigError):
-        ModelConfig(
-            materialized=Materialization.INCREMENTAL,
-            unique_key=["bar"],
-            incremental_strategy="append",
-        ).model_kind(context)
-
 
 def test_model_kind_snapshot_bigquery():
     context = DbtContext()