fix(journal-entry): add error logging for delete operation in journal… (#379)

* fix(journal-entry): add error logging for delete operation in journal entries

* fix(journal-entry): enhance error logging and add tests for delete_last_voucher functionality

* fix(journal-entry): restore enforce_journal_entry_immutability function to handle DELETE and un-reversal updates

* fix(tests): refactor delete_last_voucher tests to use insertPostedEntryWithLines for consistency

supabase/migrations/20260428160000_fix_journal_entry_immutability_delete_bypass.sql

@@ -0,0 +1,68 @@
+-- Fix: enforce_journal_entry_immutability blocks DELETE and the
+-- reversed → posted "un-reversal" UPDATE that delete_last_voucher RPC needs
+-- when removing a storno entry. The RPC sets gnubok.allow_delete, but the
+-- trigger blocks both operations unconditionally. Result: the RPC fails,
+-- even though BFNAR 2013:2 explicitly permits deletion of the last voucher
+-- in a series.
+--
+-- enforce_journal_entry_line_immutability already respects this flag;
+-- this migration brings the entries trigger in line — but narrowly.
+--
+-- Bypass scope:
+--   * DELETE: allowed when gnubok.allow_delete='true'. delete_last_voucher
+--     enforces all legal constraints (last-in-series, no references, period
+--     not locked, owner/admin) before setting the flag.
+--   * UPDATE: allowed only for the specific reversed → posted transition
+--     used to "un-reverse" the original entry when its storno is being
+--     deleted. All other UPDATE paths still go through the normal state
+--     machine — defense-in-depth on posted-entry mutation is preserved.
+
+CREATE OR REPLACE FUNCTION public.enforce_journal_entry_immutability()
+RETURNS trigger
+LANGUAGE plpgsql
+AS $function$
+BEGIN
+  IF TG_OP = 'DELETE' THEN
+    IF current_setting('gnubok.allow_delete', true) = 'true' THEN
+      RETURN OLD;
+    END IF;
+    RAISE EXCEPTION 'Cannot delete journal entries (id: %, status: %). Use cancelled status instead.',
+      OLD.id, OLD.status;
+  END IF;
+
+  IF OLD.status = 'draft' AND NEW.status IN ('draft', 'posted', 'cancelled') THEN
+    RETURN NEW;
+  END IF;
+
+  IF OLD.status = 'posted' AND NEW.status IN ('reversed', 'cancelled') THEN
+    IF NEW.status = 'reversed' THEN
+      IF NEW.description != OLD.description OR NEW.entry_date != OLD.entry_date
+         OR NEW.fiscal_period_id != OLD.fiscal_period_id
+         OR NEW.voucher_number != OLD.voucher_number
+         OR NEW.commit_method IS DISTINCT FROM OLD.commit_method
+         OR NEW.rubric_version IS DISTINCT FROM OLD.rubric_version
+         OR NEW.source_voucher_series IS DISTINCT FROM OLD.source_voucher_series
+         OR NEW.source_voucher_number IS DISTINCT FROM OLD.source_voucher_number THEN
+        RAISE EXCEPTION 'Cannot modify fields of a posted entry during reversal (id: %)', OLD.id;
+      END IF;
+    END IF;
+    RETURN NEW;
+  END IF;
+
+  -- Narrow un-reversal path: when delete_last_voucher removes a storno entry,
+  -- it flips the original from 'reversed' back to 'posted'. No other fields
+  -- may change, and the bypass flag must be set.
+  IF OLD.status = 'reversed' AND NEW.status = 'posted'
+     AND current_setting('gnubok.allow_delete', true) = 'true' THEN
+    IF NEW.description != OLD.description OR NEW.entry_date != OLD.entry_date
+       OR NEW.fiscal_period_id != OLD.fiscal_period_id
+       OR NEW.voucher_number != OLD.voucher_number THEN
+      RAISE EXCEPTION 'Cannot modify fields during un-reversal (id: %)', OLD.id;
+    END IF;
+    RETURN NEW;
+  END IF;
+
+  RAISE EXCEPTION 'Cannot modify a % journal entry (id: %). Committed entries are immutable per Bokforingslagen.',
+    OLD.status, OLD.id;
+END;
+$function$;