fix(finance): scope workbook import row lock

backend/finance/payroll/workbook_import.py

@@ -486,6 +486,15 @@ def _ensure_import_allowed(period: PayrollPeriod):
         _error("PERIOD_INPUTS_LOCKED", "Сначала верните текущий расчёт на исправление.")
 
 
+def _period_import_lock_queryset():
+    # current_run is nullable, so PostgreSQL must lock only the period table.
+    # Locking every joined table raises an error for the outer join when a
+    # period has no current run.
+    return PayrollPeriod.objects.select_for_update(of=("self",)).select_related(
+        "current_run"
+    )
+
+
 @transaction.atomic
 def apply_workbook_import(
     period_id: int,
@@ -515,11 +524,7 @@ def apply_workbook_import(
             "WORKBOOK_CHANGED",
             "После предпросмотра выбран другой файл. Повторите проверку.",
         )
-    period = (
-        PayrollPeriod.objects.select_for_update()
-        .select_related("current_run")
-        .get(pk=period_id)
-    )
+    period = _period_import_lock_queryset().get(pk=period_id)
     _ensure_import_allowed(period)
     if period.lock_version != expected_period_lock_version:
         _error("STALE_PERIOD", "Период уже изменён; повторите предпросмотр.")

backend/tests/finance/test_payroll_workbook_import.py

@@ -10,7 +10,11 @@ from django.urls import reverse
 from openpyxl import Workbook
 
 from finance.models import PayrollDailyWorkEntry, PayrollPeriod, PayrollWorkRecord
-from finance.payroll.workbook_import import _sanitize_styles, parse_workbook
+from finance.payroll.workbook_import import (
+    _period_import_lock_queryset,
+    _sanitize_styles,
+    parse_workbook,
+)
 
 pytestmark = pytest.mark.django_db
 
@@ -64,6 +68,13 @@ def make_period(creator):
     )
 
 
+def test_import_period_lock_targets_only_the_period_table():
+    query = _period_import_lock_queryset().query
+
+    assert query.select_for_update is True
+    assert query.select_for_update_of == ("self",)
+
+
 def test_invalid_legacy_colour_can_be_repaired_before_parsing():
     payload = workbook_bytes()
     source = zipfile.ZipFile(io.BytesIO(payload))