handle unset default editions

bookwyrm/activitypub/book.py

@@ -49,6 +49,7 @@ class Edition(Book):
 class Work(Book):
     ''' work instance of a book object '''
     lccn: str = ''
+    defaultEdition: str = ''
     editions: List[str]
     type: str = 'Work'
 

bookwyrm/migrations/0018_auto_20201128_2142.py

@@ -0,0 +1,24 @@
+# Generated by Django 3.0.7 on 2020-11-28 21:42
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('bookwyrm', '0017_auto_20201128_1849'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='edition',
+            name='parent_work',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, related_name='editions', to='bookwyrm.Work'),
+        ),
+        migrations.AlterField(
+            model_name='tag',
+            name='name',
+            field=models.CharField(max_length=100, unique=True),
+        ),
+    ]

bookwyrm/models/book.py

@@ -86,6 +86,7 @@ class Book(ActivitypubMixin, BookWyrmModel):
 
         ActivityMapping('lccn', 'lccn'),
         ActivityMapping('editions', 'editions'),
+        ActivityMapping('defaultEdition', 'default_edition'),
         ActivityMapping('cover', 'cover'),
     ]
 
@@ -125,6 +126,10 @@ class Work(OrderedCollectionPageMixin, Book):
         null=True
     )
 
+    def get_default_edition(self):
+        ''' in case the default edition is not set '''
+        return self.default_edition or self.editions.first()
+
     activity_serializer = activitypub.Work
 
 

bookwyrm/views.py

@@ -531,7 +531,7 @@ def book_page(request, book_id):
         return JsonResponse(book.to_activity(), encoder=ActivityEncoder)
 
     if isinstance(book, models.Work):
-        book = book.default_edition
+        book = book.get_default_edition()
     if not book:
         return HttpResponseNotFound()
 
@@ -646,7 +646,7 @@ def author_page(request, author_id):
     data = {
         'title': author.name,
         'author': author,
-        'books': [b.default_edition for b in books],
+        'books': [b.get_default_edition() for b in books],
     }
     return TemplateResponse(request, 'author.html', data)