fix(migrations): adjust retention expiry trigger and validation for fiscal periods (#1104)

supabase/migrations/20260721132000_correct_bfl_retention_expiry.sql

@@ -20,14 +20,35 @@ $$;
 
 -- PostgreSQL fires triggers with the same timing alphabetically. The zz
 -- prefix makes this legal correction run after the original migration 017
--- trigger without modifying that shipped enforcement migration.
+-- trigger without modifying that shipped enforcement migration. It must run
+-- on every update because the original calculate_retention_expiry trigger also
+-- runs on every update and would otherwise restore the old, too-early date.
+DROP TRIGGER IF EXISTS zz_set_bfl_retention_expiry ON public.fiscal_periods;
+
 CREATE TRIGGER zz_set_bfl_retention_expiry
-  BEFORE INSERT OR UPDATE OF period_end ON public.fiscal_periods
+  BEFORE INSERT OR UPDATE ON public.fiscal_periods
   FOR EACH ROW EXECUTE FUNCTION public.set_bfl_retention_expiry();
 
+-- The period-start validator depends only on company_id and period_start.
+-- Restrict UPDATE execution to those columns so retention and other metadata
+-- backfills do not revalidate unchanged historical period dates.
+DROP TRIGGER IF EXISTS enforce_period_start_day ON public.fiscal_periods;
+
+CREATE TRIGGER enforce_period_start_day
+  BEFORE INSERT OR UPDATE OF company_id, period_start ON public.fiscal_periods
+  FOR EACH ROW
+  EXECUTE FUNCTION public.enforce_first_of_month_for_subsequent_periods();
+
 UPDATE public.fiscal_periods
 SET retention_expires_at = make_date(
   extract(year FROM period_end)::integer + 8,
   1,
   1
+)
+WHERE retention_expires_at IS DISTINCT FROM make_date(
+  extract(year FROM period_end)::integer + 8,
+  1,
+  1
 );
+
+NOTIFY pgrst, 'reload schema';