Fixed #32219 -- Made InlineModelAdmin.verbose_name_plural fallback to its verbose_name.

django/contrib/admin/options.py

@@ -2037,10 +2037,13 @@ class InlineModelAdmin(BaseModelAdmin):
         self.opts = self.model._meta
         self.has_registered_model = admin_site.is_registered(self.model)
         super().__init__()
+        if self.verbose_name_plural is None:
+            if self.verbose_name is None:
+                self.verbose_name_plural = self.model._meta.verbose_name_plural
+            else:
+                self.verbose_name_plural = format_lazy('{}s', self.verbose_name)
         if self.verbose_name is None:
             self.verbose_name = self.model._meta.verbose_name
-        if self.verbose_name_plural is None:
-            self.verbose_name_plural = self.model._meta.verbose_name_plural
 
     @property
     def media(self):

docs/ref/contrib/admin/index.txt

@@ -2453,13 +2453,19 @@ The ``InlineModelAdmin`` class adds or customizes:
 
 .. attribute:: InlineModelAdmin.verbose_name
 
-    An override to the ``verbose_name`` found in the model's inner ``Meta``
-    class.
+    An override to the :attr:`~django.db.models.Options.verbose_name` from the
+    model's inner ``Meta`` class.
 
 .. attribute:: InlineModelAdmin.verbose_name_plural
 
-    An override to the ``verbose_name_plural`` found in the model's inner
-    ``Meta`` class.
+    An override to the :attr:`~django.db.models.Options.verbose_name_plural`
+    from the model's inner ``Meta`` class. If this isn't given and the
+    :attr:`.InlineModelAdmin.verbose_name` is defined, Django will use
+    :attr:`.InlineModelAdmin.verbose_name` + ``'s'``.
+
+    .. versionchanged:: 4.0
+
+        The fallback to :attr:`.InlineModelAdmin.verbose_name` was added.
 
 .. attribute:: InlineModelAdmin.can_delete
 

docs/releases/4.0.txt

@@ -85,6 +85,9 @@ Minor features
 * The new :attr:`.ModelAdmin.search_help_text` attribute allows specifying a
   descriptive text for the search box.
 
+* The :attr:`.InlineModelAdmin.verbose_name_plural` attribute now fallbacks to
+  the :attr:`.InlineModelAdmin.verbose_name` + ``'s'``.
+
 :mod:`django.contrib.admindocs`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/admin_inlines/tests.py

@@ -967,6 +967,55 @@ class TestReadOnlyChangeViewInlinePermissions(TestCase):
 class TestVerboseNameInlineForms(TestDataMixin, TestCase):
     factory = RequestFactory()
 
+    def test_verbose_name_inline(self):
+        class NonVerboseProfileInline(TabularInline):
+            model = Profile
+            verbose_name = 'Non-verbose childs'
+
+        class VerboseNameProfileInline(TabularInline):
+            model = VerboseNameProfile
+            verbose_name = 'Childs with verbose name'
+
+        class VerboseNamePluralProfileInline(TabularInline):
+            model = VerboseNamePluralProfile
+            verbose_name = 'Childs with verbose name plural'
+
+        class BothVerboseNameProfileInline(TabularInline):
+            model = BothVerboseNameProfile
+            verbose_name = 'Childs with both verbose names'
+
+        modeladmin = ModelAdmin(ProfileCollection, admin_site)
+        modeladmin.inlines = [
+            NonVerboseProfileInline,
+            VerboseNameProfileInline,
+            VerboseNamePluralProfileInline,
+            BothVerboseNameProfileInline,
+        ]
+        obj = ProfileCollection.objects.create()
+        url = reverse('admin:admin_inlines_profilecollection_change', args=(obj.pk,))
+        request = self.factory.get(url)
+        request.user = self.superuser
+        response = modeladmin.changeform_view(request)
+        self.assertNotContains(response, 'Add another Profile')
+        # Non-verbose model.
+        self.assertContains(response, '<h2>Non-verbose childss</h2>')
+        self.assertContains(response, 'Add another Non-verbose child')
+        self.assertNotContains(response, '<h2>Profiles</h2>')
+        # Model with verbose name.
+        self.assertContains(response, '<h2>Childs with verbose names</h2>')
+        self.assertContains(response, 'Add another Childs with verbose name')
+        self.assertNotContains(response, '<h2>Model with verbose name onlys</h2>')
+        self.assertNotContains(response, 'Add another Model with verbose name only')
+        # Model with verbose name plural.
+        self.assertContains(response, '<h2>Childs with verbose name plurals</h2>')
+        self.assertContains(response, 'Add another Childs with verbose name plural')
+        self.assertNotContains(response, '<h2>Model with verbose name plural only</h2>')
+        # Model with both verbose names.
+        self.assertContains(response, '<h2>Childs with both verbose namess</h2>')
+        self.assertContains(response, 'Add another Childs with both verbose names')
+        self.assertNotContains(response, '<h2>Model with both - plural name</h2>')
+        self.assertNotContains(response, 'Add another Model with both - name')
+
     def test_verbose_name_plural_inline(self):
         class NonVerboseProfileInline(TabularInline):
             model = Profile