Test that copying pages with M2M relations doesn't break

wagtail/tests/testapp/migrations/0014_m2m_blog_page.py

@@ -0,0 +1,49 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import wagtail.wagtailcore.fields
+import modelcluster.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wagtailcore', '0020_add_index_on_page_first_published_at'),
+        ('tests', '0013_iconsetting_notyetregisteredsetting_testsetting'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='BlogCategory',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True, serialize=False)),
+                ('name', models.CharField(unique=True, max_length=80)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='BlogCategoryBlogPage',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True, serialize=False)),
+                ('category', models.ForeignKey(to='tests.BlogCategory', related_name='+')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='ManyToManyBlogPage',
+            fields=[
+                ('page_ptr', models.OneToOneField(primary_key=True, serialize=False, parent_link=True, auto_created=True, to='wagtailcore.Page')),
+                ('body', wagtail.wagtailcore.fields.RichTextField(blank=True)),
+                ('adverts', models.ManyToManyField(to='tests.Advert', blank=True)),
+                ('blog_categories', models.ManyToManyField(to='tests.BlogCategory', through='tests.BlogCategoryBlogPage', blank=True)),
+            ],
+            options={
+                'abstract': False,
+            },
+            bases=('wagtailcore.page',),
+        ),
+        migrations.AddField(
+            model_name='blogcategoryblogpage',
+            name='page',
+            field=modelcluster.fields.ParentalKey(to='tests.ManyToManyBlogPage', related_name='categories'),
+        ),
+    ]

wagtail/tests/testapp/models.py

@@ -479,3 +479,27 @@ class IconSetting(BaseSetting):
 
 class NotYetRegisteredSetting(BaseSetting):
     pass
+
+
+class BlogCategory(models.Model):
+    name = models.CharField(unique=True, max_length=80)
+
+
+class BlogCategoryBlogPage(models.Model):
+    category = models.ForeignKey(BlogCategory, related_name="+")
+    page = ParentalKey('ManyToManyBlogPage', related_name='categories')
+    panels = [
+        FieldPanel('category'),
+    ]
+
+
+class ManyToManyBlogPage(Page):
+    """
+    A page type with two different kinds of M2M relation.
+    We don't formally support these, but we don't want them to cause
+    hard breakages either.
+    """
+    body = RichTextField(blank=True)
+    adverts = models.ManyToManyField(Advert, blank=True)
+    blog_categories = models.ManyToManyField(
+        BlogCategory, through=BlogCategoryBlogPage, blank=True)

wagtail/wagtailcore/tests/test_page_model.py

@@ -16,7 +16,8 @@ from wagtail.wagtailcore.models import Page, Site, PAGE_MODEL_CLASSES
 from wagtail.tests.testapp.models import (
     SingleEventPage, EventPage, EventIndex, SimplePage,
     BusinessIndex, BusinessSubIndex, BusinessChild, StandardIndex,
-    MTIBasePage, MTIChildPage, AbstractPage, TaggedPage)
+    MTIBasePage, MTIChildPage, AbstractPage, TaggedPage,
+    BlogCategory, BlogCategoryBlogPage, Advert, ManyToManyBlogPage)
 
 
 class TestSiteRouting(TestCase):
@@ -666,6 +667,27 @@ class TestCopyPage(TestCase):
             for item_id in new_tagged_item_ids
         ]))
 
+    def test_copy_page_with_m2m_relations(self):
+        # create and publish a ManyToManyBlogPage under Events
+        event_index = Page.objects.get(url_path='/home/events/')
+        category = BlogCategory.objects.create(name='Birds')
+        advert = Advert.objects.create(url='http://www.heinz.com/', text="beanz meanz heinz")
+
+        blog_page = ManyToManyBlogPage(title='My blog page', slug='my-blog-page')
+        event_index.add_child(instance=blog_page)
+
+        blog_page.adverts.add(advert)
+        BlogCategoryBlogPage.objects.create(category=category, page=blog_page)
+        blog_page.save_revision().publish()
+
+        # copy to underneath homepage
+        homepage = Page.objects.get(url_path='/home/')
+        new_blog_page = blog_page.copy(to=homepage)
+
+        # M2M relations are not formally supported, so for now we're only interested in
+        # the copy operation as a whole succeeding, rather than the child objects being copied
+        self.assertNotEqual(blog_page.id, new_blog_page.id)
+
 
 class TestSubpageTypeBusinessRules(TestCase):
     def test_allowed_subpage_types(self):