Fixed #25987 -- Made inline formset validation respect unique_together with an unsaved parent object.

Thanks Anton Kuzmichev for the report and Tim for the review.

2 files changed, 17 insertions, 0 deletions

diff --git a/tests/inline_formsets/models.py b/tests/inline_formsets/models.py
index d94069d5db..70f9008d8b 100644
--- a/tests/inline_formsets/models.py
+++ b/tests/inline_formsets/models.py
@@ -31,5 +31,8 @@ class Poem(models.Model):
     poet = models.ForeignKey(Poet, models.CASCADE)
     name = models.CharField(max_length=100)
 
+    class Meta:
+        unique_together = ('poet', 'name')
+
     def __str__(self):
         return self.name
diff --git a/tests/inline_formsets/tests.py b/tests/inline_formsets/tests.py
index c298f9430e..f516ae8c7b 100644
--- a/tests/inline_formsets/tests.py
+++ b/tests/inline_formsets/tests.py
@@ -162,3 +162,17 @@ class InlineFormsetFactoryTest(TestCase):
         PoemFormSet = inlineformset_factory(Poet, Poem, fields="__all__", extra=0)
         formset = PoemFormSet(None, instance=poet)
         self.assertEqual(len(formset.forms), 1)
+
+    def test_unsaved_fk_validate_unique(self):
+        poet = Poet(name='unsaved')
+        PoemFormSet = inlineformset_factory(Poet, Poem, fields=['name'])
+        data = {
+            'poem_set-TOTAL_FORMS': '2',
+            'poem_set-INITIAL_FORMS': '0',
+            'poem_set-MAX_NUM_FORMS': '2',
+            'poem_set-0-name': 'Poem',
+            'poem_set-1-name': 'Poem',
+        }
+        formset = PoemFormSet(data, instance=poet)
+        self.assertFalse(formset.is_valid())
+        self.assertEqual(formset.non_form_errors(), ['Please correct the duplicate data for name.'])