[GitHub] [airflow] msb217 commented on a change in pull request #7596: [AIRFLOW-6870] remove imports from models module

[GitBox <gi...@apache.org>]

msb217 commented on a change in pull request #7596: [AIRFLOW-6870] remove imports from models module
URL: https://github.com/apache/airflow/pull/7596#discussion_r386052871
 
 

 ##########
 File path: airflow/models/__init__.py
 ##########
 @@ -16,25 +16,36 @@
 # specific language governing permissions and limitations
 # under the License.
 """Airflow models"""
-from airflow.models.base import ID_LEN, Base
-from airflow.models.baseoperator import BaseOperator, BaseOperatorLink
-from airflow.models.connection import Connection
-from airflow.models.dag import DAG, DagModel, DagTag
-from airflow.models.dagbag import DagBag
-from airflow.models.dagpickle import DagPickle
-from airflow.models.dagrun import DagRun
-from airflow.models.errors import ImportError  # pylint: disable=redefined-builtin
-from airflow.models.log import Log
-from airflow.models.pool import Pool
-from airflow.models.skipmixin import SkipMixin
-from airflow.models.slamiss import SlaMiss
-from airflow.models.taskfail import TaskFail
-from airflow.models.taskinstance import TaskInstance, clear_task_instances
-from airflow.models.taskreschedule import TaskReschedule
-from airflow.models.variable import Variable
-from airflow.models.xcom import XCOM_RETURN_KEY, XCom
-
-try:
-    from airflow.models.kubernetes import KubeResourceVersion, KubeWorkerIdentifier
-except ImportError:
-    pass
+
+# flake8: noqa: F401
+# pylint: disable=wrong-import-position
+import sys
+
+__all__ = ['BaseOperator', 'BaseOperatorLink']
+PY37 = sys.version_info >= (3, 7)
+
+def __getattr__(name):
+    # PEP-562: Lazy loaded attributes on python modules
+    if name == "BaseOperator":
+        from airflow.models.baseoperator import BaseOperator  # pylint: disable=redefined-outer-name
+        return BaseOperator
+    if name == "BaseOperator":
+        from airflow.models.baseoperator import BaseOperatorLink  # pylint: disable=redefined-outer-name
+        return BaseOperatorLink
+    raise AttributeError(f"module {__name__} has no attribute {name}")
+
+
+# This is never executed, but tricks static analyzers (PyDev, PyCharm,
+# pylint, etc.) into knowing the types of these symbols, and what
+# they contain.
+STATICA_HACK = True
+globals()['kcah_acitats'[::-1].upper()] = False
+if STATICA_HACK:  # pragma: no cover
+    from airflow.models.baseoperator import BaseOperator
+    from airflow.models.baseoperator import BaseOperatorLink
+
+
+if not PY37:
+    from pep562 import Pep562
+
+    Pep562(__name__)
 
 Review comment:
   In order preserve workflows - I have utilized the same technique for loading `BaseOperator` into `airflow/models/__init__.py` as in [AIRFLOW-6817] of lazy loading `airflow.DAG` into `airflow/__init__.py`. 
   
   This lazy loading technique allows for both pre-commit hooks to pass
   ```Make sure BaseOperator[Link] is imported from airflow.models.baseoperator```
   ```Make sure BaseOperator[Link] is imported from airflow.models outside of core```
   
   Maybe more user-facing modules such as `Variable` should be added in this way? I only added `BaseOperator` as it was the only module required in order to satisfy pre-commit hooks.

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