Replace wrong usage of prefetch_related with select_related (#12602)

prefetch_related should be used for many-to-many and one-to-many
relationships, while select_related is for foreign key and one-to-one
relationships. Otherwise, we are doing an extra query instead of saving
one.

Author: stsewd

readthedocs/organizations/filters.py

@@ -41,7 +41,7 @@ def get_team_queryset(self):
         return Team.objects.member(
             self.request.user,
             organization=self.organization,
-        ).prefetch_related("organization")
+        ).select_related("organization")
 
 
 class OrganizationSortOrderingFilter(OrderingFilter):

readthedocs/organizations/migrations/0008_migrate_old_invitations.py

@@ -19,7 +19,7 @@ def forwards_func(apps, schema_editor):
     Invitation = apps.get_model("invitations", "Invitation")
     ContentType = apps.get_model("contenttypes", "ContentType")
 
-    queryset = TeamInvite.objects.filter(teammember__member__isnull=True).prefetch_related(
+    queryset = TeamInvite.objects.filter(teammember__member__isnull=True).select_related(
         "organization"
     )
     for team_invite in queryset:

readthedocs/organizations/views/base.py

@@ -172,7 +172,7 @@ class OrganizationOwnerView(OrganizationMixin):
     def get_queryset(self):
         return OrganizationOwner.objects.filter(
             organization=self.get_organization(),
-        ).prefetch_related("owner")
+        ).select_related("owner")
 
     def get_form(self, data=None, files=None, **kwargs):
         kwargs["organization"] = self.get_organization()

readthedocs/subscriptions/notifications.py

@@ -31,7 +31,7 @@ def for_subscriptions():
         return (
             djstripe.Subscription.readthedocs.trial_ending()
             .created_days_ago(24)
-            .prefetch_related("customer__rtd_organization")
+            .select_related("customer__rtd_organization")
         )