Handle foreign key on stage items (#701)

fix https://github.com/evroon/bracket/issues/629

backend/bracket/routes/stage_items.py

@@ -32,6 +32,7 @@ from bracket.sql.stage_items import (
 )
 from bracket.sql.stages import get_full_tournament_details
 from bracket.sql.validation import check_foreign_keys_belong_to_tournament
+from bracket.utils.errors import ForeignKey, check_foreign_key_violation
 from bracket.utils.id_types import StageItemId, TournamentId
 
 router = APIRouter()
@@ -44,11 +45,16 @@ async def delete_stage_item(
     tournament_id: TournamentId,
     stage_item_id: StageItemId,
     _: UserPublic = Depends(user_authenticated_for_tournament),
-    stage_item: StageItemWithRounds = Depends(stage_item_dependency),
+    __: StageItemWithRounds = Depends(stage_item_dependency),
 ) -> SuccessResponse:
-    await sql_delete_stage_item_with_foreign_keys(stage_item_id)
-    await recalculate_ranking_for_tournament_id(tournament_id)
-    return SuccessResponse()
+    with check_foreign_key_violation(
+        {
+            ForeignKey.matches_team1_winner_from_stage_item_id_fkey,
+        }
+    ):
+        await sql_delete_stage_item_with_foreign_keys(stage_item_id)
+        await recalculate_ranking_for_tournament_id(tournament_id)
+        return SuccessResponse()
 
 
 @router.post("/tournaments/{tournament_id}/stage_items", response_model=SuccessResponse)

backend/bracket/utils/errors.py

@@ -21,6 +21,7 @@ class ForeignKey(EnumAutoStr):
     stage_item_inputs_team_id_fkey = auto()
     matches_team1_id_fkey = auto()
     matches_team2_id_fkey = auto()
+    matches_team1_winner_from_stage_item_id_fkey = auto()
 
 
 unique_index_violation_error_lookup = {
@@ -35,6 +36,8 @@ foreign_key_violation_error_lookup = {
     ForeignKey.stage_item_inputs_team_id_fkey: "This team is still used in stage items",
     ForeignKey.matches_team1_id_fkey: "This team is still part of matches",
     ForeignKey.matches_team2_id_fkey: "This team is still part of matches",
+    ForeignKey.matches_team1_winner_from_stage_item_id_fkey: "This stage item is referenced by "
+    "other stage items",
 }
 
 

frontend/src/components/forms/user.tsx

@@ -110,7 +110,7 @@ export default function UserForm({ user, t, i18n }: { user: UserInterface; t: an
       </Tabs.Panel>
       <Tabs.Panel value="language" pt="xs">
         <Select
-          clearable={false}
+          allowDeselect={false}
           value={i18n.language}
           label={t('language')}
           data={locales}