From ddd30f331c7a2af38176d72d9ce2265068984bed Mon Sep 17 00:00:00 2001
From: Eugen Rochko <eugen@zeonfederated.com>
Date: Wed, 17 Oct 2018 17:13:04 +0200
Subject: [PATCH] Improve support for aspects/circles (#8950)

* Add silent column to mentions

* Save silent mentions in ActivityPub Create handler and optimize it

Move networking calls out of the database transaction

* Add "limited" visibility level masked as "private" in the API

Unlike DMs, limited statuses are pushed into home feeds. The access
control rules between direct and limited statuses is almost the same,
except for counter and conversation logic

* Ensure silent column is non-null, add spec

* Ensure filters don't check silent mentions for blocks/mutes

As those are "this person is also allowed to see" rather than "this
person is involved", therefore does not warrant filtering

* Clean up code

* Use Status#active_mentions to limit returned mentions

* Fix code style issues

* Use Status#active_mentions in Notification

And remove stream_entry eager-loading from Notification
---
 app/lib/activitypub/activity.rb               |  2 +-
 app/lib/activitypub/activity/create.rb        | 24 ++++++++++++++-
 app/lib/activitypub/tag_manager.rb            |  6 ++--
 app/lib/feed_manager.rb                       |  8 ++---
 app/lib/formatter.rb                          |  2 +-
 app/lib/ostatus/atom_serializer.rb            |  2 +-
 app/models/account_conversation.rb            |  2 +-
 app/models/mention.rb                         |  8 +++++
 app/models/notification.rb                    |  2 +-
 app/models/status.rb                          | 15 ++++++----
 app/models/stream_entry.rb                    |  2 +-
 app/policies/status_policy.rb                 |  8 ++---
 .../activitypub/note_serializer.rb            |  2 +-
 app/serializers/rest/status_serializer.rb     | 13 ++++++++-
 app/services/batched_remove_status_service.rb |  2 +-
 app/services/fan_out_on_write_service.rb      | 12 ++++++++
 app/services/remove_status_service.rb         |  2 +-
 .../stream_entries/_detailed_status.html.haml |  2 +-
 .../activitypub/distribution_worker.rb        |  2 +-
 .../activitypub/reply_distribution_worker.rb  |  6 +---
 .../20181010141500_add_silent_to_mentions.rb  | 23 +++++++++++++++
 db/schema.rb                                  |  3 +-
 spec/lib/activitypub/activity/create_spec.rb  | 29 +++++++++++++++++++
 23 files changed, 142 insertions(+), 35 deletions(-)
 create mode 100644 db/migrate/20181010141500_add_silent_to_mentions.rb

diff --git a/app/lib/activitypub/activity.rb b/app/lib/activitypub/activity.rb
index 3a39b723ed13f..999954cb5bc99 100644
--- a/app/lib/activitypub/activity.rb
+++ b/app/lib/activitypub/activity.rb
@@ -96,7 +96,7 @@ class ActivityPub::Activity
   end
 
   def notify_about_mentions(status)
-    status.mentions.includes(:account).each do |mention|
+    status.active_mentions.includes(:account).each do |mention|
       next unless mention.account.local? && audience_includes?(mention.account)
       NotifyService.new.call(mention.account, mention)
     end
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 73475bf0295ff..7e6702a6344ae 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -28,6 +28,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
 
     process_status_params
     process_tags
+    process_audience
 
     ApplicationRecord.transaction do
       @status = Status.create!(@params)
@@ -66,6 +67,27 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     end
   end
 
+  def process_audience
+    (as_array(@object['to']) + as_array(@object['cc'])).uniq.each do |audience|
+      next if audience == ActivityPub::TagManager::COLLECTIONS[:public]
+
+      # Unlike with tags, there is no point in resolving accounts we don't already
+      # know here, because silent mentions would only be used for local access
+      # control anyway
+      account = account_from_uri(audience)
+
+      next if account.nil? || @mentions.any? { |mention| mention.account_id == account.id }
+
+      @mentions << Mention.new(account: account, silent: true)
+
+      # If there is at least one silent mention, then the status can be considered
+      # as a limited-audience status, and not strictly a direct message
+      next unless @params[:visibility] == :direct
+
+      @params[:visibility] = :limited
+    end
+  end
+
   def attach_tags(status)
     @tags.each do |tag|
       status.tags << tag
@@ -113,7 +135,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
 
     return if account.nil?
 
-    @mentions << Mention.new(account: account)
+    @mentions << Mention.new(account: account, silent: false)
   end
 
   def process_emoji(tag)
diff --git a/app/lib/activitypub/tag_manager.rb b/app/lib/activitypub/tag_manager.rb
index 95d1cf9f35326..be3a562d00cdf 100644
--- a/app/lib/activitypub/tag_manager.rb
+++ b/app/lib/activitypub/tag_manager.rb
@@ -58,8 +58,8 @@ class ActivityPub::TagManager
       [COLLECTIONS[:public]]
     when 'unlisted', 'private'
       [account_followers_url(status.account)]
-    when 'direct'
-      status.mentions.map { |mention| uri_for(mention.account) }
+    when 'direct', 'limited'
+      status.active_mentions.map { |mention| uri_for(mention.account) }
     end
   end
 
@@ -80,7 +80,7 @@ class ActivityPub::TagManager
       cc << COLLECTIONS[:public]
     end
 
-    cc.concat(status.mentions.map { |mention| uri_for(mention.account) }) unless status.direct_visibility?
+    cc.concat(status.active_mentions.map { |mention| uri_for(mention.account) }) unless status.direct_visibility? || status.limited_visibility?
 
     cc
   end
diff --git a/app/lib/feed_manager.rb b/app/lib/feed_manager.rb
index b10e5dd244cbd..3d7db27211a63 100644
--- a/app/lib/feed_manager.rb
+++ b/app/lib/feed_manager.rb
@@ -88,7 +88,7 @@ class FeedManager
     end
 
     query.each do |status|
-      next if status.direct_visibility? || filter?(:home, status, into_account)
+      next if status.direct_visibility? || status.limited_visibility? || filter?(:home, status, into_account)
       add_to_feed(:home, into_account.id, status)
     end
 
@@ -156,12 +156,12 @@ class FeedManager
     return true  if status.reply? && (status.in_reply_to_id.nil? || status.in_reply_to_account_id.nil?)
     return true  if phrase_filtered?(status, receiver_id, :home)
 
-    check_for_blocks = status.mentions.pluck(:account_id)
+    check_for_blocks = status.active_mentions.pluck(:account_id)
     check_for_blocks.concat([status.account_id])
 
     if status.reblog?
       check_for_blocks.concat([status.reblog.account_id])
-      check_for_blocks.concat(status.reblog.mentions.pluck(:account_id))
+      check_for_blocks.concat(status.reblog.active_mentions.pluck(:account_id))
     end
 
     return true if blocks_or_mutes?(receiver_id, check_for_blocks, :home)
@@ -188,7 +188,7 @@ class FeedManager
     # This filter is called from NotifyService, but already after the sender of
     # the notification has been checked for mute/block. Therefore, it's not
     # necessary to check the author of the toot for mute/block again
-    check_for_blocks = status.mentions.pluck(:account_id)
+    check_for_blocks = status.active_mentions.pluck(:account_id)
     check_for_blocks.concat([status.in_reply_to_account]) if status.reply? && !status.in_reply_to_account_id.nil?
 
     should_filter   = blocks_or_mutes?(receiver_id, check_for_blocks, :mentions)                                                         # Filter if it's from someone I blocked, in reply to someone I blocked, or mentioning someone I blocked (or muted)
diff --git a/app/lib/formatter.rb b/app/lib/formatter.rb
index 35d5a09b76693..d13884ec81868 100644
--- a/app/lib/formatter.rb
+++ b/app/lib/formatter.rb
@@ -27,7 +27,7 @@ class Formatter
       return html.html_safe # rubocop:disable Rails/OutputSafety
     end
 
-    linkable_accounts = status.mentions.map(&:account)
+    linkable_accounts = status.active_mentions.map(&:account)
     linkable_accounts << status.account
 
     html = raw_content
diff --git a/app/lib/ostatus/atom_serializer.rb b/app/lib/ostatus/atom_serializer.rb
index 1a0a635b3dcee..7a181fb404563 100644
--- a/app/lib/ostatus/atom_serializer.rb
+++ b/app/lib/ostatus/atom_serializer.rb
@@ -354,7 +354,7 @@ class OStatus::AtomSerializer
     append_element(entry, 'summary', status.spoiler_text, 'xml:lang': status.language) if status.spoiler_text?
     append_element(entry, 'content', Formatter.instance.format(status).to_str || '.', type: 'html', 'xml:lang': status.language)
 
-    status.mentions.sort_by(&:id).each do |mentioned|
+    status.active_mentions.sort_by(&:id).each do |mentioned|
       append_element(entry, 'link', nil, rel: :mentioned, 'ostatus:object-type': OStatus::TagManager::TYPES[:person], href: OStatus::TagManager.instance.uri_for(mentioned.account))
     end
 
diff --git a/app/models/account_conversation.rb b/app/models/account_conversation.rb
index a7205ec1a8b8e..c12c8d233fbc9 100644
--- a/app/models/account_conversation.rb
+++ b/app/models/account_conversation.rb
@@ -85,7 +85,7 @@ class AccountConversation < ApplicationRecord
     private
 
     def participants_from_status(recipient, status)
-      ((status.mentions.pluck(:account_id) + [status.account_id]).uniq - [recipient.id]).sort
+      ((status.active_mentions.pluck(:account_id) + [status.account_id]).uniq - [recipient.id]).sort
     end
   end
 
diff --git a/app/models/mention.rb b/app/models/mention.rb
index 8ab886b184340..d01a88e32eb97 100644
--- a/app/models/mention.rb
+++ b/app/models/mention.rb
@@ -8,6 +8,7 @@
 #  created_at :datetime         not null
 #  updated_at :datetime         not null
 #  account_id :bigint(8)
+#  silent     :boolean          default(FALSE), not null
 #
 
 class Mention < ApplicationRecord
@@ -18,10 +19,17 @@ class Mention < ApplicationRecord
 
   validates :account, uniqueness: { scope: :status }
 
+  scope :active, -> { where(silent: false) }
+  scope :silent, -> { where(silent: true) }
+
   delegate(
     :username,
     :acct,
     to: :account,
     prefix: true
   )
+
+  def active?
+    !silent?
+  end
 end
diff --git a/app/models/notification.rb b/app/models/notification.rb
index b9bec08086c21..78b180301a5ba 100644
--- a/app/models/notification.rb
+++ b/app/models/notification.rb
@@ -24,7 +24,7 @@ class Notification < ApplicationRecord
     favourite:      'Favourite',
   }.freeze
 
-  STATUS_INCLUDES = [:account, :application, :stream_entry, :media_attachments, :tags, mentions: :account, reblog: [:stream_entry, :account, :application, :media_attachments, :tags, mentions: :account]].freeze
+  STATUS_INCLUDES = [:account, :application, :media_attachments, :tags, active_mentions: :account, reblog: [:account, :application, :media_attachments, :tags, active_mentions: :account]].freeze
 
   belongs_to :account, optional: true
   belongs_to :from_account, class_name: 'Account', optional: true
diff --git a/app/models/status.rb b/app/models/status.rb
index f61bd0fee41e0..b18cb56b21d43 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -37,7 +37,7 @@ class Status < ApplicationRecord
 
   update_index('statuses#status', :proper) if Chewy.enabled?
 
-  enum visibility: [:public, :unlisted, :private, :direct], _suffix: :visibility
+  enum visibility: [:public, :unlisted, :private, :direct, :limited], _suffix: :visibility
 
   belongs_to :application, class_name: 'Doorkeeper::Application', optional: true
 
@@ -51,7 +51,8 @@ class Status < ApplicationRecord
   has_many :favourites, inverse_of: :status, dependent: :destroy
   has_many :reblogs, foreign_key: 'reblog_of_id', class_name: 'Status', inverse_of: :reblog, dependent: :destroy
   has_many :replies, foreign_key: 'in_reply_to_id', class_name: 'Status', inverse_of: :thread
-  has_many :mentions, dependent: :destroy
+  has_many :mentions, dependent: :destroy, inverse_of: :status
+  has_many :active_mentions, -> { active }, class_name: 'Mention', inverse_of: :status
   has_many :media_attachments, dependent: :nullify
 
   has_and_belongs_to_many :tags
@@ -89,7 +90,7 @@ class Status < ApplicationRecord
                    :status_stat,
                    :tags,
                    :stream_entry,
-                   mentions: :account,
+                   active_mentions: :account,
                    reblog: [
                      :account,
                      :application,
@@ -98,7 +99,7 @@ class Status < ApplicationRecord
                      :media_attachments,
                      :conversation,
                      :status_stat,
-                     mentions: :account,
+                     active_mentions: :account,
                    ],
                    thread: :account
 
@@ -171,7 +172,11 @@ class Status < ApplicationRecord
   end
 
   def hidden?
-    private_visibility? || direct_visibility?
+    private_visibility? || direct_visibility? || limited_visibility?
+  end
+
+  def distributable?
+    public_visibility? || unlisted_visibility?
   end
 
   def with_media?
diff --git a/app/models/stream_entry.rb b/app/models/stream_entry.rb
index a2f273281b6df..1a9afc5c7b743 100644
--- a/app/models/stream_entry.rb
+++ b/app/models/stream_entry.rb
@@ -48,7 +48,7 @@ class StreamEntry < ApplicationRecord
   end
 
   def mentions
-    orphaned? ? [] : status.mentions.map(&:account)
+    orphaned? ? [] : status.active_mentions.map(&:account)
   end
 
   private
diff --git a/app/policies/status_policy.rb b/app/policies/status_policy.rb
index 6addc8a8a8ebe..64a5111fc8f89 100644
--- a/app/policies/status_policy.rb
+++ b/app/policies/status_policy.rb
@@ -12,7 +12,7 @@ class StatusPolicy < ApplicationPolicy
   end
 
   def show?
-    if direct?
+    if requires_mention?
       owned? || mention_exists?
     elsif private?
       owned? || following_author? || mention_exists?
@@ -22,7 +22,7 @@ class StatusPolicy < ApplicationPolicy
   end
 
   def reblog?
-    !direct? && (!private? || owned?) && show? && !blocking_author?
+    !requires_mention? && (!private? || owned?) && show? && !blocking_author?
   end
 
   def favourite?
@@ -41,8 +41,8 @@ class StatusPolicy < ApplicationPolicy
 
   private
 
-  def direct?
-    record.direct_visibility?
+  def requires_mention?
+    record.direct_visibility? || record.limited_visibility?
   end
 
   def owned?
diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index 82b7ffe95cb87..c9d23e25fa854 100644
--- a/app/serializers/activitypub/note_serializer.rb
+++ b/app/serializers/activitypub/note_serializer.rb
@@ -68,7 +68,7 @@ class ActivityPub::NoteSerializer < ActiveModel::Serializer
   end
 
   def virtual_tags
-    object.mentions.to_a.sort_by(&:id) + object.tags + object.emojis
+    object.active_mentions.to_a.sort_by(&:id) + object.tags + object.emojis
   end
 
   def atom_uri
diff --git a/app/serializers/rest/status_serializer.rb b/app/serializers/rest/status_serializer.rb
index 61423f9615193..1f2f46b7e68b3 100644
--- a/app/serializers/rest/status_serializer.rb
+++ b/app/serializers/rest/status_serializer.rb
@@ -36,6 +36,17 @@ class REST::StatusSerializer < ActiveModel::Serializer
     !current_user.nil?
   end
 
+  def visibility
+    # This visibility is masked behind "private"
+    # to avoid API changes because there are no
+    # UX differences
+    if object.limited_visibility?
+      'private'
+    else
+      object.visibility
+    end
+  end
+
   def uri
     OStatus::TagManager.instance.uri_for(object)
   end
@@ -88,7 +99,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   end
 
   def ordered_mentions
-    object.mentions.to_a.sort_by(&:id)
+    object.active_mentions.to_a.sort_by(&:id)
   end
 
   class ApplicationSerializer < ActiveModel::Serializer
diff --git a/app/services/batched_remove_status_service.rb b/app/services/batched_remove_status_service.rb
index 2fcb3cc66bb0a..b8ab58938de8a 100644
--- a/app/services/batched_remove_status_service.rb
+++ b/app/services/batched_remove_status_service.rb
@@ -12,7 +12,7 @@ class BatchedRemoveStatusService < BaseService
   def call(statuses)
     statuses = Status.where(id: statuses.map(&:id)).includes(:account, :stream_entry).flat_map { |status| [status] + status.reblogs.includes(:account, :stream_entry).to_a }
 
-    @mentions = statuses.map { |s| [s.id, s.mentions.includes(:account).to_a] }.to_h
+    @mentions = statuses.map { |s| [s.id, s.active_mentions.includes(:account).to_a] }.to_h
     @tags     = statuses.map { |s| [s.id, s.tags.pluck(:name)] }.to_h
 
     @stream_entry_batches  = []
diff --git a/app/services/fan_out_on_write_service.rb b/app/services/fan_out_on_write_service.rb
index 5ddddf3a90435..7f2a9177545b3 100644
--- a/app/services/fan_out_on_write_service.rb
+++ b/app/services/fan_out_on_write_service.rb
@@ -10,6 +10,8 @@ class FanOutOnWriteService < BaseService
 
     if status.direct_visibility?
       deliver_to_own_conversation(status)
+    elsif status.limited_visibility?
+      deliver_to_mentioned_followers(status)
     else
       deliver_to_self(status) if status.account.local?
       deliver_to_followers(status)
@@ -53,6 +55,16 @@ class FanOutOnWriteService < BaseService
     end
   end
 
+  def deliver_to_mentioned_followers(status)
+    Rails.logger.debug "Delivering status #{status.id} to limited followers"
+
+    status.mentions.includes(:account).each do |mention|
+      mentioned_account = mention.account
+      next if !mentioned_account.local? || !mentioned_account.following?(status.account) || FeedManager.instance.filter?(:home, status, mention.account_id)
+      FeedManager.instance.push_to_home(mentioned_account, status)
+    end
+  end
+
   def render_anonymous_payload(status)
     @payload = InlineRenderer.render(status, nil, :status)
     @payload = Oj.dump(event: :update, payload: @payload)
diff --git a/app/services/remove_status_service.rb b/app/services/remove_status_service.rb
index 1ee645e6d8b26..11d28e783d04c 100644
--- a/app/services/remove_status_service.rb
+++ b/app/services/remove_status_service.rb
@@ -8,7 +8,7 @@ class RemoveStatusService < BaseService
     @status       = status
     @account      = status.account
     @tags         = status.tags.pluck(:name).to_a
-    @mentions     = status.mentions.includes(:account).to_a
+    @mentions     = status.active_mentions.includes(:account).to_a
     @reblogs      = status.reblogs.to_a
     @stream_entry = status.stream_entry
     @options      = options
diff --git a/app/views/stream_entries/_detailed_status.html.haml b/app/views/stream_entries/_detailed_status.html.haml
index 0b204d4374cd9..6e6d0eda858f2 100644
--- a/app/views/stream_entries/_detailed_status.html.haml
+++ b/app/views/stream_entries/_detailed_status.html.haml
@@ -51,7 +51,7 @@
     - if status.direct_visibility?
       %span.detailed-status__link<
         = fa_icon('envelope')
-    - elsif status.private_visibility?
+    - elsif status.private_visibility? || status.limited_visibility?
       %span.detailed-status__link<
         = fa_icon('lock')
     - else
diff --git a/app/workers/activitypub/distribution_worker.rb b/app/workers/activitypub/distribution_worker.rb
index c2bfd4f2f13b4..17c1ef7fffb54 100644
--- a/app/workers/activitypub/distribution_worker.rb
+++ b/app/workers/activitypub/distribution_worker.rb
@@ -23,7 +23,7 @@ class ActivityPub::DistributionWorker
   private
 
   def skip_distribution?
-    @status.direct_visibility?
+    @status.direct_visibility? || @status.limited_visibility?
   end
 
   def relayable?
diff --git a/app/workers/activitypub/reply_distribution_worker.rb b/app/workers/activitypub/reply_distribution_worker.rb
index fe99fc05f2956..c0ed3a1f40ee5 100644
--- a/app/workers/activitypub/reply_distribution_worker.rb
+++ b/app/workers/activitypub/reply_distribution_worker.rb
@@ -9,7 +9,7 @@ class ActivityPub::ReplyDistributionWorker
     @status  = Status.find(status_id)
     @account = @status.thread&.account
 
-    return if @account.nil? || skip_distribution?
+    return unless @account.present? && @status.distributable?
 
     ActivityPub::DeliveryWorker.push_bulk(inboxes) do |inbox_url|
       [signed_payload, @status.account_id, inbox_url]
@@ -20,10 +20,6 @@ class ActivityPub::ReplyDistributionWorker
 
   private
 
-  def skip_distribution?
-    @status.private_visibility? || @status.direct_visibility?
-  end
-
   def inboxes
     @inboxes ||= @account.followers.inboxes
   end
diff --git a/db/migrate/20181010141500_add_silent_to_mentions.rb b/db/migrate/20181010141500_add_silent_to_mentions.rb
new file mode 100644
index 0000000000000..dbb4fba263714
--- /dev/null
+++ b/db/migrate/20181010141500_add_silent_to_mentions.rb
@@ -0,0 +1,23 @@
+require Rails.root.join('lib', 'mastodon', 'migration_helpers')
+
+class AddSilentToMentions < ActiveRecord::Migration[5.2]
+  include Mastodon::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  def up
+    safety_assured do
+      add_column_with_default(
+        :mentions,
+        :silent,
+        :boolean,
+        allow_null: false,
+        default: false
+      )
+    end
+  end
+
+  def down
+    remove_column :mentions, :silent
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index bf6ab4e68cff1..f79f26f16e2cb 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_10_07_025445) do
+ActiveRecord::Schema.define(version: 2018_10_10_141500) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -301,6 +301,7 @@ ActiveRecord::Schema.define(version: 2018_10_07_025445) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.bigint "account_id"
+    t.boolean "silent", default: false, null: false
     t.index ["account_id", "status_id"], name: "index_mentions_on_account_id_and_status_id", unique: true
     t.index ["status_id"], name: "index_mentions_on_status_id"
   end
diff --git a/spec/lib/activitypub/activity/create_spec.rb b/spec/lib/activitypub/activity/create_spec.rb
index 62b9db8c24d25..cd20b7c7cb006 100644
--- a/spec/lib/activitypub/activity/create_spec.rb
+++ b/spec/lib/activitypub/activity/create_spec.rb
@@ -105,6 +105,31 @@ RSpec.describe ActivityPub::Activity::Create do
       end
     end
 
+    context 'limited' do
+      let(:recipient) { Fabricate(:account) }
+
+      let(:object_json) do
+        {
+          id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+          type: 'Note',
+          content: 'Lorem ipsum',
+          to: ActivityPub::TagManager.instance.uri_for(recipient),
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.visibility).to eq 'limited'
+      end
+
+      it 'creates silent mention' do
+        status = sender.statuses.first
+        expect(status.mentions.first).to be_silent
+      end
+    end
+
     context 'direct' do
       let(:recipient) { Fabricate(:account) }
 
@@ -114,6 +139,10 @@ RSpec.describe ActivityPub::Activity::Create do
           type: 'Note',
           content: 'Lorem ipsum',
           to: ActivityPub::TagManager.instance.uri_for(recipient),
+          tag: {
+            type: 'Mention',
+            href: ActivityPub::TagManager.instance.uri_for(recipient),
+          },
         }
       end