fix: suppress use_managed_iceberg warning for non-Iceberg projects

CHANGELOG.md

@@ -9,6 +9,7 @@
 - Validate relation identifier length at creation time and raise a clear error when it exceeds Databricks' 255-character limit ([#1309](https://github.com/databricks/dbt-databricks/issues/1309))
 - Fix spurious `MicrobatchConcurrency` behavior-change warning firing on every run regardless of whether the project contained microbatch models ([#1406](https://github.com/databricks/dbt-databricks/issues/1406))
 - Fix DBR capability cache being permanently poisoned by a transient version-query failure ([#1398](https://github.com/databricks/dbt-databricks/issues/1398))
+- Fix spurious `use_managed_iceberg` behavior-change warning firing on every run for projects that don't use Iceberg ([#1266](https://github.com/databricks/dbt-databricks/issues/1266))
 
 ## dbt-databricks 1.11.7 (Apr 17, 2026)
 

dbt/adapters/databricks/impl.py

@@ -248,7 +248,9 @@ def __init__(self, config: Any, mp_context: SpawnContext) -> None:
         self.add_catalog_integration(constants.DEFAULT_HIVE_METASTORE_CATALOG)
 
         # Store the use_managed_iceberg flag in GlobalState for the session
-        GlobalState.set_use_managed_iceberg(bool(self.behavior.use_managed_iceberg))
+        GlobalState.set_use_managed_iceberg(
+            self.get_behavior_flag_no_warn(USE_MANAGED_ICEBERG["name"])
+        )
 
     @property
     def _behavior_flags(self) -> list[BehaviorFlag]:
@@ -262,8 +264,7 @@ def _behavior_flags(self) -> list[BehaviorFlag]:
 
     def supports(self, capability: Capability) -> bool:
         if capability == Capability.MicrobatchConcurrency:
-            # `.no_warn` avoids a BehaviorChangeEvent on dbt-core's per-parse probe.
-            return self.behavior.use_concurrent_microbatch.no_warn
+            return self.get_behavior_flag_no_warn(USE_CONCURRENT_MICROBATCH["name"])
         return super().supports(capability)
 
     def quote(self, identifier):  # type: ignore[override,no-untyped-def]
@@ -281,7 +282,7 @@ def is_uniform(self, config: BaseConfig) -> bool:
                     ", 'table', or 'snapshot'."
                 )
             if (
-                self.behavior.use_managed_iceberg
+                self.get_behavior_flag_no_warn(USE_MANAGED_ICEBERG["name"])
                 and catalog_relation.catalog_type != constants.UNITY_CATALOG_TYPE
             ):
                 raise DbtConfigError(
@@ -290,7 +291,7 @@ def is_uniform(self, config: BaseConfig) -> bool:
                 )
             # UniForm refers to Delta tables with Iceberg compatibility.
             # Native managed Iceberg tables don't need Delta properties.
-            return not self.behavior.use_managed_iceberg
+            return not self.get_behavior_flag_no_warn(USE_MANAGED_ICEBERG["name"])
         else:
             return False
 
@@ -770,6 +771,16 @@ def _get_columns_for_catalog(  # type: ignore[override]
             as_dict["column_type"] = as_dict.pop("dtype")
             yield as_dict
 
+    def get_behavior_flag_no_warn(self, behavior_flag_name: str) -> bool:
+        """Get the value of a behavior flag without triggering a warning.
+
+        dbt logs a warning the first time a behavior flag with a False value is accessed. Use
+        this method to access the value of a behavior flag without triggering a warning.
+        """
+        # As intended - This method will error out if the behavior flag is missing.
+        behavior_flag = getattr(self.behavior, behavior_flag_name)
+        return behavior_flag.no_warn
+
     def add_query(
         self,
         sql: str,

dbt/include/databricks/macros/relations/file_format.sql

@@ -13,7 +13,7 @@
   {% endif %}
 
   {#-- Use managed Iceberg if behavior flag is enabled and table_format is iceberg --#}
-  {% if adapter.behavior.use_managed_iceberg and table_format == 'iceberg' %}
+  {% if table_format == 'iceberg' and adapter.behavior.use_managed_iceberg %}
     using iceberg
   {% else %}
     using {{ file_format }}

tests/unit/macros/relations/test_table_macros.py

@@ -339,3 +339,39 @@ def test_macros_create_table_as_uniform_iceberg(self, config, template_bundle):
             "'delta.universalFormat.enabledFormats' = 'iceberg') as select 1"
         )
         assert sql == expected
+
+
+class TestFileFormatClause(MacroTestBase):
+    """Regression tests for `file_format_clause` short-circuit behavior.
+
+    For non-Iceberg models, the macro must not read `adapter.behavior.use_managed_iceberg`,
+    since that access fires a BehaviorChangeEvent deprecation warning on every run.
+    """
+
+    @pytest.fixture(scope="class")
+    def template_name(self) -> str:
+        return "file_format.sql"
+
+    @pytest.fixture(scope="class")
+    def macro_folders_to_load(self) -> list:
+        return ["macros/relations", "macros"]
+
+    def test_file_format_clause_does_not_access_flag_for_non_iceberg(self, template_bundle):
+        """Non-Iceberg relations must short-circuit before reading the behavior flag."""
+
+        class ErrorOnUseManagedIcebergAccess:
+            @property
+            def use_managed_iceberg(self):
+                raise AssertionError(
+                    "use_managed_iceberg must not be accessed when table_format != 'iceberg'"
+                )
+
+        template_bundle.context["adapter"].behavior = ErrorOnUseManagedIcebergAccess()
+        catalog_relation = unity_relation(
+            table_format=constants.DEFAULT_TABLE_FORMAT,
+            file_format=constants.DELTA_FILE_FORMAT,
+        )
+
+        sql = self.run_macro(template_bundle.template, "file_format_clause", catalog_relation)
+
+        assert sql == "using delta"

tests/unit/test_adapter.py

@@ -1282,7 +1282,7 @@ def test_is_uniform_with_managed_iceberg_returns_false(
 
         Native managed Iceberg tables don't use UniForm (Delta with Iceberg compatibility),
         so they shouldn't get Delta table properties added."""
-        adapter.behavior.use_managed_iceberg = True
+        adapter.behavior.use_managed_iceberg.setting = True
         adapter.build_catalog_relation = Mock(
             return_value=unity_catalog_relation_managed_iceberg_relation
         )
@@ -1295,7 +1295,7 @@ def test_is_uniform_with_uniform_iceberg_returns_true(
         self, adapter, mock_config, unity_catalog_relation
     ):
         """Test that is_uniform returns True for UniForm Iceberg tables"""
-        adapter.behavior.use_managed_iceberg = False  # Default
+        adapter.behavior.use_managed_iceberg.setting = False  # Default
         adapter.build_catalog_relation = Mock(return_value=unity_catalog_relation)
         adapter.has_capability = Mock(return_value=True)  # Has iceberg capability
 
@@ -1318,7 +1318,7 @@ def test_is_uniform_with_managed_iceberg_hive_metastore_error(
         self, adapter, mock_config, hive_catalog_relation
     ):
         """Test that is_uniform raises error for managed Iceberg with Hive Metastore"""
-        adapter.behavior.use_managed_iceberg = True
+        adapter.behavior.use_managed_iceberg.setting = True
         adapter.build_catalog_relation = Mock(return_value=hive_catalog_relation)
         adapter.has_capability = Mock(return_value=True)  # Has iceberg capability
 
@@ -1331,7 +1331,7 @@ def test_is_uniform_with_old_dbr_version_error(
         self, adapter, mock_config, unity_catalog_relation
     ):
         """Test that is_uniform raises error for insufficient DBR version"""
-        adapter.behavior.use_managed_iceberg = False
+        adapter.behavior.use_managed_iceberg.setting = False
         adapter.build_catalog_relation = Mock(return_value=unity_catalog_relation)
         adapter.has_capability = Mock(return_value=False)  # No ICEBERG capability
 
@@ -1342,7 +1342,7 @@ def test_is_uniform_with_invalid_materialization_error(
         self, adapter, mock_config, unity_catalog_relation
     ):
         """Test that is_uniform raises error for invalid materialization"""
-        adapter.behavior.use_managed_iceberg = False
+        adapter.behavior.use_managed_iceberg.setting = False
         adapter.build_catalog_relation = Mock(return_value=unity_catalog_relation)
         adapter.has_capability = Mock(return_value=True)  # Has iceberg capability
         mock_config.get.side_effect = lambda key: "view" if key == "materialized" else None