[2.1.x] Fixed #29723 -- Fixed crash if InlineModelAdmin.has_add_permission() doesn't accept the obj argument.

* Refs #27991 -- Added testing for ModelAdmin.get_inline_instances() if the inline's has_add_permission() doesn't accept 'obj'.

* Fixed #29723 -- Fixed crash if InlineModelAdmin.has_add_permission() doesn't accept the obj argument.

Backport of fd8a7a5313f5e223212085b2e470e43c0047e066 from master

django/contrib/admin/options.py

@@ -584,13 +584,8 @@ class ModelAdmin(BaseModelAdmin):
         inline_instances = []
         for inline_class in self.inlines:
             inline = inline_class(self.model, self.admin_site)
-            # RemovedInDjango30Warning: obj will be a required argument.
-            args = get_func_args(inline.has_add_permission)
-            if 'obj' in args:
-                inline_has_add_permission = inline.has_add_permission(request, obj)
-            else:
-                inline_has_add_permission = inline.has_add_permission(request)
             if request:
+                inline_has_add_permission = inline._has_add_permission(request, obj)
                 if not (inline.has_view_or_change_permission(request, obj) or
                         inline_has_add_permission or
                         inline.has_delete_permission(request, obj)):
@@ -1483,7 +1478,7 @@ class ModelAdmin(BaseModelAdmin):
         for inline, formset in zip(inline_instances, formsets):
             fieldsets = list(inline.get_fieldsets(request, obj))
             readonly = list(inline.get_readonly_fields(request, obj))
-            has_add_permission = inline.has_add_permission(request, obj)
+            has_add_permission = inline._has_add_permission(request, obj)
             has_change_permission = inline.has_change_permission(request, obj)
             has_delete_permission = inline.has_delete_permission(request, obj)
             has_view_permission = inline.has_view_permission(request, obj)
@@ -2001,6 +1996,11 @@ class InlineModelAdmin(BaseModelAdmin):
             js.append('collapse%s.js' % extra)
         return forms.Media(js=['admin/js/%s' % url for url in js])
 
+    def _has_add_permission(self, request, obj):
+        # RemovedInDjango30Warning: obj will be a required argument.
+        args = get_func_args(self.has_add_permission)
+        return self.has_add_permission(request, obj) if 'obj' in args else self.has_add_permission(request)
+
     def get_extra(self, request, obj=None, **kwargs):
         """Hook for customizing the number of extra inline forms."""
         return self.extra
@@ -2046,7 +2046,7 @@ class InlineModelAdmin(BaseModelAdmin):
 
         base_model_form = defaults['form']
         can_change = self.has_change_permission(request, obj) if request else True
-        can_add = self.has_add_permission(request, obj) if request else True
+        can_add = self._has_add_permission(request, obj) if request else True
 
         class DeleteProtectedModelForm(base_model_form):
 

docs/releases/2.1.1.txt

@@ -46,3 +46,6 @@ Bugfixes
   ``values_list()`` after combining querysets with ``extra()`` with
   ``union()``, ``difference()``, or ``intersection()`` crashed due to
   mismatching columns (:ticket:`29694`).
+
+* Fixed crash if ``InlineModelAdmin.has_add_permission()`` doesn't accept the
+  ``obj`` argument (:ticket:`29723`).

tests/modeladmin/test_has_add_permission_obj_deprecation.py

@@ -1,4 +1,8 @@
+from datetime import date
+
 from django.contrib.admin.options import ModelAdmin, TabularInline
+from django.contrib.admin.sites import AdminSite
+from django.test import TestCase
 from django.utils.deprecation import RemovedInDjango30Warning
 
 from .models import Band, Song
@@ -56,3 +60,45 @@ class HasAddPermissionObjTests(CheckTestCase):
         )
         with self.assertWarnsMessage(RemovedInDjango30Warning, msg):
             self.assertIsValid(BandAdmin, Band)
+
+
+class MockRequest:
+    method = 'POST'
+    FILES = {}
+    POST = {}
+
+
+class SongInline(TabularInline):
+    model = Song
+
+    def has_add_permission(self, request):
+        return True
+
+
+class BandAdmin(ModelAdmin):
+    inlines = [SongInline]
+
+
+class ModelAdminTests(TestCase):
+
+    def setUp(self):
+        self.band = Band.objects.create(name='The Doors', bio='', sign_date=date(1965, 1, 1))
+        self.song = Song.objects.create(name='test', band=self.band)
+        self.site = AdminSite()
+        self.request = MockRequest()
+        self.request.user = self.MockAddUser()
+        self.ma = BandAdmin(Band, self.site)
+
+    class MockAddUser:
+        def has_perm(self, perm):
+            return perm == 'modeladmin.add_band'
+
+    def test_get_inline_instances(self):
+        self.assertEqual(len(self.ma.get_inline_instances(self.request)), 1)
+
+    def test_get_inline_formsets(self):
+        formsets, inline_instances = self.ma._create_formsets(self.request, self.band, change=True)
+        self.assertEqual(len(self.ma.get_inline_formsets(self.request, formsets, inline_instances)), 1)
+
+    def test_get_formsets_with_inlines(self):
+        self.assertEqual(len(list(self.ma. get_formsets_with_inlines(self.request, self.band))), 1)