Infinite scrolling and comment migration

judge/migrations/0152_migrate_comments.py

@@ -0,0 +1,54 @@
+from django.db import migrations, models
+import django.db.models.deletion
+from django.core.exceptions import ObjectDoesNotExist
+
+
+def migrate_comments(apps, schema_editor):
+    Comment = apps.get_model("judge", "Comment")
+    Problem = apps.get_model("judge", "Problem")
+    Solution = apps.get_model("judge", "Solution")
+    BlogPost = apps.get_model("judge", "BlogPost")
+    Contest = apps.get_model("judge", "Contest")
+
+    for comment in Comment.objects.all():
+        page = comment.page
+        try:
+            if page.startswith("p:"):
+                code = page[2:]
+                comment.linked_object = Problem.objects.get(code=code)
+            elif page.startswith("s:"):
+                code = page[2:]
+                comment.linked_object = Solution.objects.get(problem__code=code)
+            elif page.startswith("c:"):
+                key = page[2:]
+                comment.linked_object = Contest.objects.get(key=key)
+            elif page.startswith("b:"):
+                blog_id = page[2:]
+                comment.linked_object = BlogPost.objects.get(id=blog_id)
+            comment.save()
+        except ObjectDoesNotExist:
+            comment.delete()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("contenttypes", "0002_remove_content_type_name"),
+        ("judge", "0151_comment_content_type"),
+    ]
+
+    operations = [
+        migrations.RunPython(migrate_comments, migrations.RunPython.noop, atomic=True),
+        migrations.AlterField(
+            model_name="comment",
+            name="content_type",
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.CASCADE,
+                to="contenttypes.contenttype",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="comment",
+            name="object_id",
+            field=models.PositiveIntegerField(),
+        ),
+    ]