set up Literal for synchronize_session

Fixes: #8280
Change-Id: I59bc6cc0483375f79e17952188e0c2cde926502c

2 files changed, 9 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/persistence.py b/lib/sqlalchemy/orm/persistence.py
index 0c035e7cf..c10f4701e 100644
--- a/lib/sqlalchemy/orm/persistence.py
+++ b/lib/sqlalchemy/orm/persistence.py
@@ -55,6 +55,7 @@ from ..sql.dml import InsertDMLState
 from ..sql.dml import UpdateDMLState
 from ..sql.elements import BooleanClauseList
 from ..sql.selectable import LABEL_STYLE_TABLENAME_PLUS_COL
+from ..util.typing import Literal
 
 if TYPE_CHECKING:
     from .mapper import Mapper
@@ -65,6 +66,9 @@ if TYPE_CHECKING:
 _O = TypeVar("_O", bound=object)
 
 
+_SynchronizeSessionArgument = Literal[False, "evaluate", "fetch"]
+
+
 def _bulk_insert(
     mapper: Mapper[_O],
     mappings: Union[Iterable[InstanceState[_O]], Iterable[Dict[str, Any]]],
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index a29e368b6..99131e3e9 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -99,6 +99,7 @@ if TYPE_CHECKING:
     from ._typing import _InternalEntityType
     from .mapper import Mapper
     from .path_registry import PathRegistry
+    from .persistence import _SynchronizeSessionArgument
     from .session import _PKIdentityArgument
     from .session import Session
     from .state import InstanceState
@@ -2969,7 +2970,9 @@ class Query(
             self._legacy_from_self(col).enable_eagerloads(False).scalar()
         )
 
-    def delete(self, synchronize_session: str = "evaluate") -> int:
+    def delete(
+        self, synchronize_session: _SynchronizeSessionArgument = "evaluate"
+    ) -> int:
         r"""Perform a DELETE with an arbitrary WHERE clause.
 
         Deletes rows matched by this query from the database.
@@ -3030,7 +3033,7 @@ class Query(
     def update(
         self,
         values: Dict[_DMLColumnArgument, Any],
-        synchronize_session: str = "evaluate",
+        synchronize_session: _SynchronizeSessionArgument = "evaluate",
         update_args: Optional[Dict[Any, Any]] = None,
     ) -> int:
         r"""Perform an UPDATE with an arbitrary WHERE clause.