Merge branch 'fix-corpus-deletion' into 'master'

Delete elements before types when removing a corpus

See merge request !488

arkindex/documents/models.py

@@ -44,6 +44,15 @@ class Corpus(models.Model):
     def __str__(self):
         return self.name
 
+    def delete(self):
+        """
+        Override the normal deletion process to delete elements before deleting the corpus:
+        prevents a ProtectedError when element types are being deleted before elements.
+        """
+        with transaction.atomic():
+            self.elements.all().delete()
+            super().delete()
+
     def get_acl_rights(self, user):
         '''
         List Access rights on this corpus for this user

arkindex/documents/tests/test_corpus.py

 from django.contrib.auth.models import AnonymousUser
+from django.db.models import Model, ProtectedError
 from django.urls import reverse
 from rest_framework import status
 
@@ -342,3 +343,22 @@ class TestCorpus(FixtureAPITestCase):
     def test_delete_requires_login(self):
         response = self.client.delete(reverse('api:corpus-retrieve', kwargs={'pk': self.corpus_private.id}))
         self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
+
+    def test_delete_elements_first(self):
+        """
+        Ensure corpus deletion deletes elements first to prevent a ProtectedError
+        """
+        self.assertEqual(Corpus.objects.count(), 3)
+        self.assertEqual(Element.objects.count(), 19)
+
+        # Use Django's default deletion method and expect a ProtectedError
+        with self.assertRaises(ProtectedError):
+            Model.delete(self.corpus)
+
+        self.assertEqual(Corpus.objects.count(), 3)
+        self.assertEqual(Element.objects.count(), 19)
+
+        # Use the corpus deletion method and it works!
+        self.corpus.delete()
+        self.assertEqual(Corpus.objects.count(), 2)
+        self.assertEqual(Element.objects.count(), 0)