fix: unify delete logic and fix cascade deletion for flows (#5466)

* Fix incomplete cascade deletion for flows.

* [autofix.ci] apply automated fixes

* Remove modification.

* [autofix.ci] apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

src/backend/base/langflow/api/utils.py

@@ -283,6 +283,11 @@ async def cascade_delete_flow(session: AsyncSession, flow_id: uuid.UUID) -> None
     try:
         await session.exec(delete(TransactionTable).where(TransactionTable.flow_id == flow_id))
         await session.exec(delete(VertexBuildTable).where(VertexBuildTable.flow_id == flow_id))
+        # TODO: Verify if deleting messages is safe in terms of session id relevance
+        # If we delete messages directly, rather than setting flow_id to null,
+        # it might cause unexpected behaviors because the session id could still be
+        # used elsewhere to search for these messages.
+        # await session.exec(delete(MessageTable).where(MessageTable.flow_id == flow_id))
         await session.exec(delete(Flow).where(Flow.id == flow_id))
     except Exception as e:
         msg = f"Unable to cascade delete flow: ${flow_id}"

src/backend/base/langflow/api/v1/flows.py

@@ -25,8 +25,6 @@ from langflow.services.database.models.flow.model import FlowHeader
 from langflow.services.database.models.flow.utils import get_webhook_component_in_flow
 from langflow.services.database.models.folder.constants import DEFAULT_FOLDER_NAME
 from langflow.services.database.models.folder.model import Folder
-from langflow.services.database.models.transactions.crud import get_transactions_by_flow_id
-from langflow.services.database.models.vertex_builds.crud import get_vertex_builds_by_flow_id
 from langflow.services.deps import get_settings_service
 from langflow.services.settings.service import SettingsService
 
@@ -423,15 +421,7 @@ async def delete_multiple_flows(
             await db.exec(select(Flow).where(col(Flow.id).in_(flow_ids)).where(Flow.user_id == user.id))
         ).all()
         for flow in flows_to_delete:
-            transactions_to_delete = await get_transactions_by_flow_id(db, flow.id)
-            for transaction in transactions_to_delete:
-                await db.delete(transaction)
-
-            builds_to_delete = await get_vertex_builds_by_flow_id(db, flow.id)
-            for build in builds_to_delete:
-                await db.delete(build)
-
-            await db.delete(flow)
+            await cascade_delete_flow(db, flow.id)
 
         await db.commit()
         return {"deleted": len(flows_to_delete)}