Fix more n plus 1 queries

pydis_site/apps/api/models/bot/user.py

@@ -1,3 +1,5 @@
+from functools import lru_cache
+
 from django.contrib.postgres.fields import ArrayField
 from django.core.validators import MaxValueValidator, MinValueValidator
 from django.db import models
@@ -70,14 +72,20 @@ def __str__(self):
             return f"{self.name}#{self.discriminator:04d}"
         return self.name
 
+    @staticmethod
+    @lru_cache(maxsize=256)
+    def _get_roles(role_ids: tuple[int, ...]) -> list[Role]:
+        """Fetch the given roles, cached to avoid refetching the same roles for every user."""
+        return list(Role.objects.filter(id__in=role_ids))
+
     @property
     def top_role(self) -> Role:
         """
         Attribute that returns the user's top role.
 
         This will fall back to the Developers role if the user does not have any roles.
         """
-        roles = Role.objects.filter(id__in=self.roles)
+        roles = self._get_roles(tuple(sorted(self.roles)))
         if not roles:
             return Role.objects.get(name="Developers")
         return max(roles)

pydis_site/apps/api/serializers.py

@@ -435,10 +435,11 @@ def to_representation(self, instance: FilterList) -> dict:
         into a sub-field called `settings`.
         """
         schema = {name: getattr(instance, name) for name in BASE_FILTERLIST_FIELDS}
-        schema['filters'] = [
-            FilterSerializer(many=False).to_representation(instance=item)
-            for item in Filter.objects.filter(filter_list=instance.id).prefetch_related('filter_list')
-        ]
+        filters = []
+        for item in instance.filters.all():
+            item.filter_list = instance
+            filters.append(FilterSerializer(many=False).to_representation(instance=item))
+        schema['filters'] = filters
 
         settings = {name: getattr(instance, name) for name in BASE_SETTINGS_FIELDS}
         settings['infraction_and_notification'] = {

pydis_site/apps/api/signals.py

@@ -1,4 +1,4 @@
-from django.db.models.signals import post_delete
+from django.db.models.signals import post_delete, post_save
 from django.dispatch import receiver
 
 from pydis_site.apps.api.models.bot import Role, User
@@ -10,3 +10,10 @@ def delete_role_from_user(sender: Role, instance: Role, **kwargs) -> None:
     for user in User.objects.filter(roles__contains=[instance.id]):
         del user.roles[user.roles.index(instance.id)]
         user.save()
+
+
+@receiver(signal=post_save, sender=Role)
+@receiver(signal=post_delete, sender=Role)
+def clear_top_role_cache(sender: Role, **kwargs) -> None:
+    """Clear the cached role lookups used by `User.top_role` when a role changes."""
+    User._get_roles.cache_clear()

pydis_site/apps/api/tests/test_filters.py

@@ -358,6 +358,20 @@ def test_filter_unique_constraint(self) -> None:
         response = self.client.post(test_filter.url(), data=clean_test_json(test_filter.object))
         self.assertEqual(response.status_code, 400)
 
+    def test_filter_list_includes_nested_filters(self) -> None:
+        filter_list = FilterList.objects.create(**get_test_sequences()["filter_list1"].object)
+        filter_ = Filter.objects.create(
+            filter_list=filter_list, content="bad word", description="This is a bad word."
+        )
+
+        response = self.client.get(f"{reverse('api:bot:filterlist-list')}/{filter_list.id}")
+
+        self.assertEqual(response.status_code, 200)
+        filters = response.json()["filters"]
+        self.assertEqual(len(filters), 1)
+        self.assertEqual(filters[0]["id"], filter_.id)
+        self.assertEqual(filters[0]["filter_list"], filter_list.id)
+
 
 class FilterCreationMissingOptionalFieldsTestCase(AuthenticatedAPITestCase):
     @classmethod

pydis_site/apps/staff/views.py

@@ -1,5 +1,7 @@
+from django.db.models import Prefetch
 from django.views.generic.detail import DetailView
 
+from pydis_site.apps.api.models.bot.deleted_message import DeletedMessage
 from pydis_site.apps.api.models.bot.message_deletion_context import MessageDeletionContext
 
 
@@ -9,3 +11,9 @@ class LogView(DetailView):
     model = MessageDeletionContext
     context_object_name = "deletion_context"
     template_name = "staff/logs.html"
+    queryset = MessageDeletionContext.objects.select_related("actor").prefetch_related(
+        Prefetch(
+            "deletedmessage_set",
+            queryset=DeletedMessage.objects.select_related("author"),
+        ),
+    )