Ignore `GenericRelation` when copying pages

Co-Authored-By: John-Scott Atlakson <john-scott@greenlightgo.co>

CHANGELOG.txt

@@ -9,8 +9,9 @@ Changelog
  * Fix: Allow bulk publishing of pages without revisions (Andy Chosak)
  * Fix: Ensure that all descendant pages are logged when deleting a page, not just immediate children (Jake Howard)
  * Fix: Refactor `FormPagesListView` in wagtail.contrib.forms to avoid undefined `locale` variable when subclassing (Dan Braghis)
- * Fix: page copy in Wagtail admin ignores `exclude_fields_in_copy` (John-Scott Atlakson)
+ * Fix: Page copy in Wagtail admin ignores `exclude_fields_in_copy` (John-Scott Atlakson)
  * Fix: Translation key `IntegrityError` when publishing pages with translatable `Orderable`s that were copied without being published (Kalob Taulien, Dan Braghis)
+ * Fix: Ignore `GenericRelation` when copying pages (John-Scott Atlakson)
 
 
 2.16.1 (11.02.2022)

docs/releases/2.16.2.md

@@ -17,6 +17,7 @@
  * Refactor `FormPagesListView` in wagtail.contrib.forms to avoid undefined `locale` variable when subclassing (Dan Braghis)
  * Ensure page copy in Wagtail admin doesn't ignore `exclude_fields_in_copy` (John-Scott Atlakson)
  * Generate new translation keys for translatable `Orderable`s when page is copied without being published (Kalob Taulien, Dan Braghis)
+ * Ignore `GenericRelation` when copying pages (John-Scott Atlakson)
 
 ## Upgrade considerations
 

wagtail/core/models/copying.py

@@ -1,3 +1,4 @@
+from django.contrib.contenttypes.fields import GenericRelation
 from django.db import models
 from modelcluster.fields import ParentalKey, ParentalManyToManyField
 from modelcluster.models import ClusterableModel
@@ -21,6 +22,10 @@ def _extract_field_data(source, exclude_fields=None):
         if field.auto_created:
             continue
 
+        # Ignore reverse generic relations
+        if isinstance(field, GenericRelation):
+            continue
+
         # Copy parental m2m relations
         if field.many_to_many:
             if isinstance(field, ParentalManyToManyField):

wagtail/core/tests/test_page_model.py

@@ -28,8 +28,9 @@ from wagtail.tests.testapp.models import (
     BusinessIndex, BusinessNowherePage, BusinessSubIndex, CustomManager, CustomManagerPage,
     CustomPageQuerySet, EventCategory, EventIndex, EventPage, EventPageSpeaker, GenericSnippetPage,
     ManyToManyBlogPage, MTIBasePage, MTIChildPage, MyCustomPage, OneToOnePage,
-    PageWithExcludedCopyField, SimpleChildPage, SimplePage, SimpleParentPage, SingleEventPage,
-    SingletonPage, StandardIndex, StreamPage, TaggedGrandchildPage, TaggedPage)
+    PageWithExcludedCopyField, PageWithGenericRelation, RelatedGenericRelation, SimpleChildPage,
+    SimplePage, SimpleParentPage, SingleEventPage, SingletonPage, StandardIndex, StreamPage,
+    TaggedGrandchildPage, TaggedPage)
 from wagtail.tests.utils import WagtailTestUtils
 
 
@@ -1631,6 +1632,26 @@ class TestCopyPage(TestCase):
         # special_field is in the list to be excluded
         self.assertNotEqual(page.special_field, new_page.special_field)
 
+    def test_page_with_generic_relation(self):
+        """Test that a page with a GenericRelation will have that relation ignored when
+        copying.
+        """
+        homepage = Page.objects.get(url_path="/home/")
+        original_page = homepage.add_child(
+            instance=PageWithGenericRelation(
+                title="PageWithGenericRelation",
+                slug="page-with-generic-relation",
+                live=True,
+                has_unpublished_changes=False,
+            )
+        )
+        RelatedGenericRelation.objects.create(content_object=original_page)
+        self.assertIsNotNone(original_page.generic_relation.first())
+        page_copy = original_page.copy(
+            to=homepage, update_attrs={"slug": f"{original_page.slug}-2"}
+        )
+        self.assertIsNone(page_copy.generic_relation.first())
+
     def test_copy_page_with_excluded_parental_and_child_relations(self):
         """Test that a page will be copied with parental and child relations removed if excluded."""
 

wagtail/tests/testapp/migrations/0062_pagewithgenericrelation_relatedgenericrelation.py

@@ -0,0 +1,34 @@
+# Generated by Django 3.2.12 on 2022-04-10 08:26
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wagtailcore', '0066_collection_management_permissions'),
+        ('contenttypes', '0002_remove_content_type_name'),
+        ('tests', '0061_tag_fk_for_django_4'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PageWithGenericRelation',
+            fields=[
+                ('page_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='wagtailcore.page')),
+            ],
+            options={
+                'abstract': False,
+            },
+            bases=('wagtailcore.page',),
+        ),
+        migrations.CreateModel(
+            name='RelatedGenericRelation',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('object_id', models.PositiveBigIntegerField()),
+                ('content_type', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='contenttypes.contenttype')),
+            ],
+        ),
+    ]

wagtail/tests/testapp/models.py

@@ -5,7 +5,7 @@ import uuid
 
 from django import forms
 from django.conf import settings
-from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ValidationError
 from django.core.paginator import EmptyPage, PageNotAnInteger, Paginator
@@ -169,6 +169,16 @@ class PageWithExcludedCopyField(Page):
     ]
 
 
+class RelatedGenericRelation(models.Model):
+    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
+    object_id = models.PositiveBigIntegerField()
+    content_object = GenericForeignKey("content_type", "object_id")
+
+
+class PageWithGenericRelation(Page):
+    generic_relation = GenericRelation("tests.RelatedGenericRelation")
+
+
 class PageWithOldStyleRouteMethod(Page):
     """
     Prior to Wagtail 0.4, the route() method on Page returned an HttpResponse