Remove unneeded custom 'delete_selected'

`has_delete_permission` already avoids deleting main system users

orchestra/contrib/systemusers/actions.py

@@ -128,29 +128,3 @@ def create_link(modeladmin, request, queryset):
     return TemplateResponse(request, 'admin/systemusers/systemuser/create_link.html', context)
 create_link.url_name = 'create-link'
 create_link.tool_description = _("Create link")
-
-
-def delete_selected(modeladmin, request, queryset):
-    """ wrapper arround admin.actions.delete_selected to prevent main system users deletion """
-    opts = modeladmin.model._meta
-    app_label = opts.app_label
-    # Check that the user has delete permission for the actual model
-    if not modeladmin.has_delete_permission(request):
-        raise PermissionDenied
-    else:
-        accounts = []
-        for user in queryset:
-            if user.is_main:
-                accounts.append(user.username)
-        if accounts:
-            n = len(accounts)
-            messages.error(request, ungettext(
-                "You have selected one main system user (%(accounts)s), which can not be deleted.",
-                "You have selected some main system users which can not be deleted (%(accounts)s).",
-                n) % {
-                    'accounts': ', '.join(accounts[:10]+['...'] if n > 10 else accounts)
-                }
-            )
-            return
-    return admin.actions.delete_selected(modeladmin, request, queryset)
-delete_selected.short_description = _("Delete selected %(verbose_name_plural)s")

orchestra/contrib/systemusers/admin.py

@@ -1,4 +1,4 @@
-from django.contrib import admin
+from django.contrib import admin, messages
 from django.utils.translation import ugettext_lazy as _
 
 from orchestra.admin import ExtendedModelAdmin, ChangePasswordAdminMixin
@@ -7,7 +7,7 @@ from orchestra.contrib.accounts.actions import list_accounts
 from orchestra.contrib.accounts.admin import SelectAccountAdminMixin
 from orchestra.contrib.accounts.filters import IsActiveListFilter
 
-from .actions import set_permission, create_link, delete_selected
+from .actions import set_permission, create_link
 from .filters import IsMainListFilter
 from .forms import SystemUserCreationForm, SystemUserChangeForm
 from .models import SystemUser
@@ -43,7 +43,7 @@ class SystemUserAdmin(ChangePasswordAdminMixin, SelectAccountAdminMixin, Extende
     form = SystemUserChangeForm
     ordering = ('-id',)
     change_view_actions = (set_permission, create_link)
-    actions = (disable, enable, delete_selected, list_accounts) + change_view_actions
+    actions = (disable, enable, list_accounts) + change_view_actions
 
     def display_main(self, user):
         return user.is_main
@@ -68,6 +68,12 @@ class SystemUserAdmin(ChangePasswordAdminMixin, SelectAccountAdminMixin, Extende
 
     def has_delete_permission(self, request, obj=None):
         if obj and obj.is_main:
+            self.message_user(request, _(
+                "You have selected one main system user (%(account)s), which can not be deleted.",
+                ) % {'account': obj},
+                messages.ERROR,
+            )
+
             return False
         return super(SystemUserAdmin, self).has_delete_permission(request, obj)