From 8ac873419fe66de65cdddf6a25560ed24c4e4a63 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adeodato=20Sim=C3=B3?= <dato@users.noreply.github.com>
Date: Fri, 26 Jan 2024 06:29:59 -0300
Subject: [PATCH] refactor: eagerly use a set in recipients, get_recipients

---
 bookwyrm/models/activitypub_mixin.py | 25 +++++++++++++------------
 bookwyrm/models/status.py            |  6 +++---
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/bookwyrm/models/activitypub_mixin.py b/bookwyrm/models/activitypub_mixin.py
index 41772a162..db737b8bc 100644
--- a/bookwyrm/models/activitypub_mixin.py
+++ b/bookwyrm/models/activitypub_mixin.py
@@ -152,8 +152,9 @@ class ActivitypubMixin:
         # find anyone who's tagged in a status, for example
         mentions = self.recipients if hasattr(self, "recipients") else []
 
-        # we always send activities to explicitly mentioned users' inboxes
-        recipients = [u.shared_inbox or u.inbox for u in mentions if not u.local]
+        # we always send activities to explicitly mentioned users (using shared inboxes
+        # where available to avoid duplicate submissions to a given instance)
+        recipients = {u.shared_inbox or u.inbox for u in mentions if not u.local}
 
         # unless it's a dm, all the followers should receive the activity
         if privacy != "direct":
@@ -173,18 +174,18 @@ class ActivitypubMixin:
             if user:
                 queryset = queryset.filter(following=user)
 
-            # ideally, we will send to shared inboxes for efficiency
-            shared_inboxes = (
-                queryset.filter(shared_inbox__isnull=False)
-                .values_list("shared_inbox", flat=True)
-                .distinct()
+            # as above, we prefer shared inboxes if available
+            recipients.update(
+                queryset.filter(shared_inbox__isnull=False).values_list(
+                    "shared_inbox", flat=True
+                )
             )
-            # but not everyone has a shared inbox
-            inboxes = queryset.filter(shared_inbox__isnull=True).values_list(
-                "inbox", flat=True
+            recipients.update(
+                queryset.filter(shared_inbox__isnull=True).values_list(
+                    "inbox", flat=True
+                )
             )
-            recipients += list(shared_inboxes) + list(inboxes)
-        return list(set(recipients))
+        return list(recipients)
 
     def to_activity_dataclass(self):
         """convert from a model to an activity"""
diff --git a/bookwyrm/models/status.py b/bookwyrm/models/status.py
index cc44fe2bf..0d1d0d839 100644
--- a/bookwyrm/models/status.py
+++ b/bookwyrm/models/status.py
@@ -107,14 +107,14 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
     @property
     def recipients(self):
         """tagged users who definitely need to get this status in broadcast"""
-        mentions = [u for u in self.mention_users.all() if not u.local]
+        mentions = {u for u in self.mention_users.all() if not u.local}
         if (
             hasattr(self, "reply_parent")
             and self.reply_parent
             and not self.reply_parent.user.local
         ):
-            mentions.append(self.reply_parent.user)
-        return list(set(mentions))
+            mentions.add(self.reply_parent.user)
+        return list(mentions)
 
     @classmethod
     def ignore_activity(