Deprecate components in Registry.findDataset and getDatasetType.

python/lsst/daf/butler/_butler.py

@@ -632,7 +632,10 @@ def _standardizeArgs(
             if isinstance(datasetRefOrType, DatasetType):
                 externalDatasetType = datasetRefOrType
             else:
-                internalDatasetType = self.registry.getDatasetType(datasetRefOrType)
+                parent_dataset_type, component = DatasetType.splitDatasetTypeName(datasetRefOrType)
+                internalDatasetType = self.registry.getDatasetType(parent_dataset_type)
+                if component is not None:
+                    internalDatasetType = internalDatasetType.makeComponentDatasetType(component)
 
         # Check that they are self-consistent
         if externalDatasetType is not None:
@@ -1093,17 +1096,30 @@ def _findDatasetRef(
             )
         # Always lookup the DatasetRef, even if one is given, to ensure it is
         # present in the current collection.
-        ref = self.registry.findDataset(datasetType, dataId, collections=collections, timespan=timespan)
+        if datasetType.isComponent():
+            parent_dataset_type = datasetType.makeCompositeDatasetType()
+            component = datasetType.component()
+        else:
+            parent_dataset_type = datasetType
+            component = None
+        ref = self.registry.findDataset(
+            parent_dataset_type, dataId, collections=collections, timespan=timespan
+        )
         if ref is None:
             if allowUnresolved:
-                return DatasetRef(datasetType, dataId)
+                ref = DatasetRef(datasetType, dataId)
+                if component is not None:
+                    ref = ref.makeComponentRef(component)
+                return ref
             else:
                 if collections is None:
                     collections = self.registry.defaults.collections
                 raise LookupError(
                     f"Dataset {datasetType.name} with data ID {dataId} "
                     f"could not be found in collections {collections}."
                 )
+        if component is not None:
+            ref = ref.makeComponentRef(component)
         if idNumber is not None and idNumber != ref.id:
             if collections is None:
                 collections = self.registry.defaults.collections

python/lsst/daf/butler/core/datasets/type.py

@@ -651,7 +651,11 @@ def from_simple(
                 raise ValueError(
                     f"Unable to convert a DatasetType name '{simple}' to DatasetType without a Registry"
                 )
-            return registry.getDatasetType(simple.name)
+            parent_name, component = cls.splitDatasetTypeName(simple.name)
+            dataset_type = registry.getDatasetType(parent_name)
+            if component is not None:
+                dataset_type = dataset_type.makeComponentDatasetType(component)
+            return dataset_type
 
         if universe is None and registry is None:
             raise ValueError("One of universe or registry must be provided.")

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

@@ -270,6 +270,11 @@ def find(self, name: str) -> DatasetRecordStorage | None:
         compositeName, componentName = DatasetType.splitDatasetTypeName(name)
         storage = self._byName.get(compositeName)
         if storage is not None and componentName is not None:
+            warnings.warn(
+                "Registry component dataset operations are deprecated in favor of DatasetRef methods, and "
+                "will be removed after v26.",
+                FutureWarning,
+            )
             componentStorage = copy.copy(storage)
             componentStorage.datasetType = storage.datasetType.makeComponentDatasetType(componentName)
             return componentStorage

python/lsst/daf/butler/registry/tests/_registry.py

@@ -658,14 +658,18 @@ def testComponentLookups(self):
         # DatasetRef.makeComponentRef.
         collection = "imported_g"
         parentType = registry.getDatasetType("bias")
-        childType = registry.getDatasetType("bias.wcs")
+        with self.assertWarns(FutureWarning):
+            childType = registry.getDatasetType("bias.wcs")
         parentRefResolved = registry.findDataset(
             parentType, collections=collection, instrument="Cam1", detector=1
         )
         self.assertIsInstance(parentRefResolved, DatasetRef)
         self.assertEqual(childType, parentRefResolved.makeComponentRef("wcs").datasetType)
         # Search for a single dataset with findDataset.
-        childRef1 = registry.findDataset("bias.wcs", collections=collection, dataId=parentRefResolved.dataId)
+        with self.assertWarns(FutureWarning):
+            childRef1 = registry.findDataset(
+                "bias.wcs", collections=collection, dataId=parentRefResolved.dataId
+            )
         self.assertEqual(childRef1, parentRefResolved.makeComponentRef("wcs"))
         # Search for detector data IDs constrained by component dataset
         # existence with queryDataIds.

tests/test_butler.py

@@ -395,7 +395,7 @@ def runPutGetTest(self, storageClass, datasetTypeName):
                 )
                 self.assertEqual(count, stop)
 
-            compRef = butler.registry.findDataset(compNameS, dataId, collections=butler.collections)
+            compRef = ref.makeComponentRef("summary")
             summary = butler.getDirect(compRef)
             self.assertEqual(summary, metric.summary)