Lazy-load Alembic in db_manager imports

airflow-core/src/airflow/utils/db_manager.py

@@ -20,7 +20,6 @@
 import os
 from typing import TYPE_CHECKING
 
-from alembic import command
 from sqlalchemy import inspect
 
 from airflow import settings
@@ -50,6 +49,20 @@ def _callable_accepts_use_migration_files(callable_) -> bool:
     )
 
 
+def _get_alembic_command():
+    from alembic import command
+
+    return command
+
+
+class _AlembicCommandProxy:
+    def __getattr__(self, name):
+        return getattr(_get_alembic_command(), name)
+
+
+command = _AlembicCommandProxy()
+
+
 class BaseDBManager(LoggingMixin):
     """Abstract Base DB manager for external DBs."""
 

airflow-core/tests/unit/utils/test_db_manager.py

@@ -16,6 +16,8 @@
 # under the License.
 from __future__ import annotations
 
+import subprocess
+import sys
 from contextlib import nullcontext
 from unittest import mock
 
@@ -97,6 +99,28 @@ def _create_run_db_manager(*managers):
 
 
 class TestBaseDBManager:
+    def test_importing_db_manager_does_not_eagerly_import_alembic(self):
+        result = subprocess.run(
+            [
+                sys.executable,
+                "-c",
+                (
+                    "import sys\n"
+                    "import airflow.utils.db_manager as module\n"
+                    "assert hasattr(module, 'RunDBManager')\n"
+                    "alembic_modules = sorted(\n"
+                    "    name for name in sys.modules if name == 'alembic' or name.startswith('alembic.')\n"
+                    ")\n"
+                    "assert not alembic_modules, alembic_modules\n"
+                ),
+            ],
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+
+        assert result.returncode == 0, result.stderr or result.stdout
+
     @mock.patch.object(BaseDBManager, "get_alembic_config")
     @mock.patch.object(BaseDBManager, "get_current_revision")
     @mock.patch.object(BaseDBManager, "create_db_from_orm")