fix postgres application row locking

partner_programs/services/application_team.py

@@ -124,7 +124,7 @@ def _lock_program(program: PartnerProgram) -> PartnerProgram:
 
 def _lock_application(application: Application) -> Application:
     return (
-        Application.objects.select_for_update()
+        Application.objects.select_for_update(of=("self",))
         .select_related("program", "user", "created_by", "project")
         .get(pk=application.pk)
     )

partner_programs/tests/test_application_team_service.py

@@ -5,6 +5,7 @@
 
 from partner_programs.models import Application, PartnerProgram, Team, TeamMember
 from partner_programs.services.application_team import (
+    _lock_application,
     ActiveApplicationConflictError,
     ApplicationDeadlinePassedError,
     ApplicationNotEditableError,
@@ -36,6 +37,29 @@ def setUp(self):
         self.user = create_user(prefix="team-service-owner")
         self.registration = create_program_member(self.program, user=self.user)
 
+    def test_application_lock_targets_only_application_row(self):
+        application = Application(pk=123)
+
+        with patch(
+            "partner_programs.services.application_team."
+            "Application.objects.select_for_update"
+        ) as select_for_update:
+            queryset = select_for_update.return_value
+            related_queryset = queryset.select_related.return_value
+            related_queryset.get.return_value = application
+
+            result = _lock_application(application)
+
+        select_for_update.assert_called_once_with(of=("self",))
+        queryset.select_related.assert_called_once_with(
+            "program",
+            "user",
+            "created_by",
+            "project",
+        )
+        related_queryset.get.assert_called_once_with(pk=application.pk)
+        self.assertIs(result, application)
+
     def configure_team_policy(
         self,
         *,