Switch back to returning given DatasetType in registry imports.

When the given dataset type differs from the registered dataset type
in imports, it's not clear what the ideal behavior is, but the right
choice for *this* ticket is clearly to not change that behavior.

python/lsst/daf/butler/registry/datasets/byDimensions/_manager.py

@@ -696,7 +696,7 @@ def insert(
 
     def import_(
         self,
-        dataset_type_name: str,
+        dataset_type: DatasetType,
         run: RunRecord,
         data_ids: Mapping[DatasetId, DataCoordinate],
     ) -> list[DatasetRef]:
@@ -705,8 +705,8 @@ def import_(
             # Just in case an empty mapping is provided we want to avoid
             # adding dataset type to summary tables.
             return []
-        if (storage := self._find_storage(dataset_type_name)) is None:
-            raise MissingDatasetTypeError(f"Dataset type {dataset_type_name!r} has not been registered.")
+        if (storage := self._find_storage(dataset_type.name)) is None:
+            raise MissingDatasetTypeError(f"Dataset type {dataset_type.name!r} has not been registered.")
         # Current timestamp, type depends on schema version.
         if self._use_astropy_ingest_date:
             # Astropy `now()` precision should be the same as `now()` which
@@ -751,7 +751,7 @@ def import_(
             )
             refs = [
                 DatasetRef(
-                    datasetType=storage.dataset_type,
+                    datasetType=dataset_type,
                     id=dataset_id,
                     dataId=dataId,
                     run=run.name,

python/lsst/daf/butler/registry/interfaces/_datasets.py

@@ -419,16 +419,17 @@ def insert(
     @abstractmethod
     def import_(
         self,
-        dataset_type_name: str,
+        dataset_type: DatasetType,
         run: RunRecord,
         data_ids: Mapping[DatasetId, DataCoordinate],
     ) -> list[DatasetRef]:
         """Insert one or more dataset entries into the database.
 
         Parameters
         ----------
-        dataset_type_name : `str`
-            Name of the dataset type.
+        dataset_type : `DatasetType`
+            Type of dataset to import.  Also used as the dataset type for
+            the returned refs.
         run : `RunRecord`
             The record object describing the `~CollectionType.RUN` collection
             these datasets will be associated with.

python/lsst/daf/butler/registry/sql_registry.py

@@ -1176,7 +1176,7 @@ def _importDatasets(
             data_ids = {dataset.id: dataset.dataId for dataset in datasets}
 
         try:
-            refs = list(self._managers.datasets.import_(datasetType.name, runRecord, data_ids))
+            refs = list(self._managers.datasets.import_(datasetType, runRecord, data_ids))
             if self._managers.obscore:
                 self._managers.obscore.add_datasets(refs)
         except sqlalchemy.exc.IntegrityError as err: