feat(dataset): allow "airflow.dataset.metadata.Metadata" import for b…

…ackward compat (apache#44413)

airflow/datasets/__init__.py

@@ -1,4 +1,3 @@
-#
 # Licensed to the Apache Software Foundation (ASF) under one
 # or more contributor license agreements.  See the NOTICE file
 # distributed with this work for additional information
@@ -38,8 +37,4 @@
     stacklevel=2,
 )
 
-
-__all__ = [
-    "Dataset",
-    "DatasetAlias",
-]
+__all__ = ["Dataset", "DatasetAlias"]

airflow/datasets/metadata.py

@@ -0,0 +1,33 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+from __future__ import annotations
+
+import warnings
+
+from airflow.sdk.definitions.asset.metadata import Metadata
+
+# TODO: Remove this module in Airflow 3.2
+
+warnings.warn(
+    "Import from the airflow.dataset module is deprecated and "
+    "will be removed in the Airflow 3.2. Please import it from 'airflow.sdk.definitions.asset.metadata'.",
+    DeprecationWarning,
+    stacklevel=2,
+)
+
+__all__ = ["Metadata"]

tests/datasets/test_dataset.py

@@ -40,6 +40,15 @@
                 "will be removed in the Airflow 3.2. Please import it from 'airflow.sdk.definitions.asset'."
             ),
         ),
+        (
+            "airflow.datasets.metadata",
+            "Metadata",
+            (
+                "Import from the airflow.dataset module is deprecated and "
+                "will be removed in the Airflow 3.2. Please import it from "
+                "'airflow.sdk.definitions.asset.metadata'."
+            ),
+        ),
     ),
 )
 def test_backward_compat_import_before_airflow_3_2(module_path, attr_name, warning_message):