switch to sql_compat _select

alembic/runtime/migration.py

@@ -23,7 +23,6 @@
 from typing import Union
 
 from sqlalchemy import Column
-from sqlalchemy import select
 from sqlalchemy import literal_column
 from sqlalchemy.engine import Engine
 from sqlalchemy.engine import url as sqla_url
@@ -33,6 +32,7 @@
 from .. import util
 from ..util import sqla_compat
 from ..util.compat import EncodedIO
+from ..util.sqla_compat import _select
 
 if TYPE_CHECKING:
     from sqlalchemy.engine import Dialect
@@ -530,16 +530,10 @@ def get_current_heads(self) -> Tuple[str, ...]:
             if not self._has_version_table():
                 return ()
         assert self.connection is not None
-        if util.sqla_14:
-            return tuple(
-                row[0] for row in self.connection.execute(
-                    select(self._version.c.version_num))
-            )
-        else:
-            return tuple(
-                row[0] for row in self.connection.execute(
-                    select([self._version.c.version_num]))  # type: ignore
-            )
+        return tuple(
+            row[0] for row in self.connection.execute(
+                _select(self._version.c.version_num))
+        )
 
     def _ensure_version_table(self, purge: bool = False) -> None:
         with sqla_compat._ensure_scope_for_ddl(self.connection):

tests/test_version_table.py

@@ -5,7 +5,6 @@
 from sqlalchemy import PrimaryKeyConstraint
 from sqlalchemy import String
 from sqlalchemy import Table
-from sqlalchemy.dialects import registry
 
 from alembic import migration
 from alembic.ddl import impl