Feat: Allow creating environments without changes when using selector (#3060)

Author: izeigerman

sqlmesh/core/plan/builder.py

@@ -672,6 +672,7 @@ def _ensure_new_env_with_changes(self) -> None:
             and not self._include_unmodified
             and self._context_diff.is_new_environment
             and not self._context_diff.has_snapshot_changes
+            and not self._backfill_models
         ):
             raise NoChangesPlanError(
                 "No changes were detected. Make a change or run with --include-unmodified to create a new environment without changes."

tests/core/test_integration.py

@@ -51,6 +51,7 @@
     SnapshotTableInfo,
 )
 from sqlmesh.utils.date import TimeLike, now, to_date, to_datetime, to_timestamp
+from sqlmesh.utils.errors import NoChangesPlanError
 from tests.conftest import DuckDBMetadata, SushiDataValidator
 
 
@@ -1627,6 +1628,22 @@ def test_plan_twice_with_star_macro_yields_no_diff(tmp_path: Path):
     assert not new_plan.new_snapshots
 
 
+@freeze_time("2023-01-08 15:00:00")
+def test_create_environment_no_changes_with_selector(init_and_plan_context: t.Callable):
+    context, plan = init_and_plan_context("examples/sushi")
+    context.apply(plan)
+
+    with pytest.raises(NoChangesPlanError):
+        context.plan("dev", no_prompts=True)
+
+    plan = context.plan("dev", no_prompts=True, select_models=["*top_waiters"])
+    assert not plan.missing_intervals
+    context.apply(plan)
+
+    schema_objects = context.engine_adapter.get_data_objects("sushi__dev")
+    assert {o.name for o in schema_objects} == {"top_waiters"}
+
+
 @pytest.mark.parametrize(
     "context_fixture",
     ["sushi_context", "sushi_dbt_context", "sushi_test_dbt_context", "sushi_no_default_catalog"],