From a88349af5559e2b66a5e56e736bdd2dcc47b328e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?KMY=EF=BC=88=E9=9B=AA=E3=81=82=E3=81=99=E3=81=8B=EF=BC=89?=
 <tt@kmycode.net>
Date: Thu, 30 Nov 2023 09:29:24 +0900
Subject: [PATCH] =?UTF-8?q?Add:=20#8=20=E3=82=B5=E3=83=BC=E3=82=AF?=
 =?UTF-8?q?=E3=83=AB=E6=8A=95=E7=A8=BF=E3=81=AE=E8=BB=A2=E9=80=81=20(#294)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Add: `conversations`テーブルに`ancestor_status`プロパティ

* Fix test

* Fix test more

* Add: `limited_visibility`に`Reply`を追加、`context`のURI

* Add: 外部からの`context`受信処理

* Fix test

* Add: 公開範囲「返信」

* Fix test

* Fix: 返信に返信以外の公開範囲を設定できない問題

* Add: ローカル投稿時にメンション追加・他サーバーへの転送

* Fix test

* Fix test

* Test: ローカルスレッドへの返信投稿の転送

* Test: 未知のアカウントからのメンション

* Add: 編集・削除の連合に対応

* Remove: 重複テスト

* Fix: 改善

* Add: 編集削除の転送処理・返信なのにsilentなメンションでの通知

* Fix: リプライが第三者に届かない問題

* Add: `always_sign_unsafe`

* Add: Subject

* Remove space

* Fix: 他人のスレッドの送信先一覧を非表示

* Fix: おかしいコード
---
 .../activitypub/contexts_controller.rb        |  23 ++
 .../mastodon/components/compacted_status.jsx  |  10 -
 app/javascript/mastodon/components/status.jsx |  10 -
 .../mastodon/components/status_action_bar.jsx |   2 +-
 .../mastodon/components/visibility_icon.tsx   |  11 +
 .../compose/components/privacy_dropdown.jsx   |  20 +-
 .../containers/privacy_dropdown_container.js  |   1 +
 .../features/status/components/action_bar.jsx |   5 +-
 app/javascript/mastodon/reducers/compose.js   |  23 +-
 app/lib/activitypub/activity/create.rb        |  41 ++-
 app/lib/activitypub/activity/delete.rb        |   7 +
 app/lib/activitypub/activity/update.rb        |   8 +
 app/lib/activitypub/parser/status_parser.rb   |   2 +
 app/lib/activitypub/tag_manager.rb            |  18 +-
 app/lib/feed_manager.rb                       |  18 +-
 app/lib/status_reach_finder.rb                |  12 +-
 app/models/conversation.rb                    |  15 +-
 app/models/status.rb                          |  13 +-
 app/policies/status_policy.rb                 |   7 +-
 .../activitypub/context_serializer.rb         |  21 ++
 .../activitypub/note_serializer.rb            |   9 +-
 app/services/concerns/payloadable.rb          |   3 +-
 app/services/fan_out_on_write_service.rb      |  12 +
 app/services/post_status_service.rb           |  22 +-
 app/services/process_conversation_service.rb  |  33 +++
 app/services/remove_status_service.rb         |  10 +-
 .../activitypub/distribution_worker.rb        |  23 +-
 .../forward_conversation_worker.rb            |  46 +++
 .../status_update_distribution_worker.rb      |  14 +-
 config/routes.rb                              |   1 +
 ...15001356_add_inbox_url_to_conversations.rb |  16 ++
 db/schema.rb                                  |   4 +-
 spec/lib/activitypub/activity/create_spec.rb  | 266 +++++++++++++++++-
 spec/lib/activitypub/activity/delete_spec.rb  |  21 ++
 spec/lib/activitypub/activity/update_spec.rb  |  34 +++
 spec/models/status_spec.rb                    |  10 +
 spec/policies/status_policy_spec.rb           |  52 ++++
 .../services/fan_out_on_write_service_spec.rb |  78 +++++
 spec/services/post_status_service_spec.rb     | 154 +++++++++-
 spec/services/remove_status_service_spec.rb   |  57 +++-
 .../activitypub/distribution_worker_spec.rb   |  16 ++
 .../status_update_distribution_worker_spec.rb |  44 ++-
 42 files changed, 1115 insertions(+), 77 deletions(-)
 create mode 100644 app/controllers/activitypub/contexts_controller.rb
 create mode 100644 app/serializers/activitypub/context_serializer.rb
 create mode 100644 app/services/process_conversation_service.rb
 create mode 100644 app/workers/activitypub/forward_conversation_worker.rb
 create mode 100644 db/migrate/20231115001356_add_inbox_url_to_conversations.rb

diff --git a/app/controllers/activitypub/contexts_controller.rb b/app/controllers/activitypub/contexts_controller.rb
new file mode 100644
index 0000000000..a3263ed82e
--- /dev/null
+++ b/app/controllers/activitypub/contexts_controller.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class ActivityPub::ContextsController < ActivityPub::BaseController
+  include SignatureVerification
+
+  vary_by -> { 'Signature' if authorized_fetch_mode? }
+
+  before_action :set_context
+
+  def show
+    expires_in 3.minutes, public: true
+    render json: @context,
+           serializer: ActivityPub::ContextSerializer,
+           adapter: ActivityPub::Adapter,
+           content_type: 'application/activity+json'
+  end
+
+  private
+
+  def set_context
+    @context = Conversation.find(params[:id])
+  end
+end
diff --git a/app/javascript/mastodon/components/compacted_status.jsx b/app/javascript/mastodon/components/compacted_status.jsx
index 01e1105127..263e08809c 100644
--- a/app/javascript/mastodon/components/compacted_status.jsx
+++ b/app/javascript/mastodon/components/compacted_status.jsx
@@ -61,16 +61,6 @@ export const defaultMediaVisibility = (status) => {
 };
 
 const messages = defineMessages({
-  public_short: { id: 'privacy.public.short', defaultMessage: 'Public' },
-  unlisted_short: { id: 'privacy.unlisted.short', defaultMessage: 'Unlisted' },
-  public_unlisted_short: { id: 'privacy.public_unlisted.short', defaultMessage: 'Public unlisted' },
-  login_short: { id: 'privacy.login.short', defaultMessage: 'Login only' },
-  private_short: { id: 'privacy.private.short', defaultMessage: 'Followers only' },
-  limited_short: { id: 'privacy.limited.short', defaultMessage: 'Limited menbers only' },
-  mutual_short: { id: 'privacy.mutual.short', defaultMessage: 'Mutual followers only' },
-  circle_short: { id: 'privacy.circle.short', defaultMessage: 'Circle members only' },
-  personal_short: { id: 'privacy.personal.short', defaultMessage: 'Yourself only' },
-  direct_short: { id: 'privacy.direct.short', defaultMessage: 'Mentioned people only' },
   edited: { id: 'status.edited', defaultMessage: 'Edited {date}' },
 });
 
diff --git a/app/javascript/mastodon/components/status.jsx b/app/javascript/mastodon/components/status.jsx
index cf6a924d27..69919c7490 100644
--- a/app/javascript/mastodon/components/status.jsx
+++ b/app/javascript/mastodon/components/status.jsx
@@ -76,16 +76,6 @@ export const defaultMediaVisibility = (status) => {
 };
 
 const messages = defineMessages({
-  public_short: { id: 'privacy.public.short', defaultMessage: 'Public' },
-  unlisted_short: { id: 'privacy.unlisted.short', defaultMessage: 'Unlisted' },
-  public_unlisted_short: { id: 'privacy.public_unlisted.short', defaultMessage: 'Public unlisted' },
-  login_short: { id: 'privacy.login.short', defaultMessage: 'Login only' },
-  private_short: { id: 'privacy.private.short', defaultMessage: 'Followers only' },
-  limited_short: { id: 'privacy.limited.short', defaultMessage: 'Limited menbers only' },
-  mutual_short: { id: 'privacy.mutual.short', defaultMessage: 'Mutual followers only' },
-  circle_short: { id: 'privacy.circle.short', defaultMessage: 'Circle members only' },
-  personal_short: { id: 'privacy.personal.short', defaultMessage: 'Yourself only' },
-  direct_short: { id: 'privacy.direct.short', defaultMessage: 'Mentioned people only' },
   edited: { id: 'status.edited', defaultMessage: 'Edited {date}' },
 });
 
diff --git a/app/javascript/mastodon/components/status_action_bar.jsx b/app/javascript/mastodon/components/status_action_bar.jsx
index 583c5fdedd..6e355de6e9 100644
--- a/app/javascript/mastodon/components/status_action_bar.jsx
+++ b/app/javascript/mastodon/components/status_action_bar.jsx
@@ -336,7 +336,7 @@ class StatusActionBar extends ImmutablePureComponent {
     }
 
     if (signedIn) {
-      if (writtenByMe) {
+      if (writtenByMe && status.get('limited_scope') !== 'reply') {
         menu.push({ text: intl.formatMessage(messages.mentions), action: this.handleOpenMentions });
       }
 
diff --git a/app/javascript/mastodon/components/visibility_icon.tsx b/app/javascript/mastodon/components/visibility_icon.tsx
index acb405c29f..c7e2707c91 100644
--- a/app/javascript/mastodon/components/visibility_icon.tsx
+++ b/app/javascript/mastodon/components/visibility_icon.tsx
@@ -8,6 +8,7 @@ import { ReactComponent as LoginIcon } from '@material-symbols/svg-600/outlined/
 import { ReactComponent as LockIcon } from '@material-symbols/svg-600/outlined/lock.svg';
 import { ReactComponent as LockOpenIcon } from '@material-symbols/svg-600/outlined/no_encryption.svg';
 import { ReactComponent as PublicIcon } from '@material-symbols/svg-600/outlined/public.svg';
+import { ReactComponent as ReplyIcon } from '@material-symbols/svg-600/outlined/reply.svg';
 import { ReactComponent as LimitedIcon } from '@material-symbols/svg-600/outlined/shield.svg';
 import { ReactComponent as PersonalIcon } from '@material-symbols/svg-600/outlined/sticky_note.svg';
 
@@ -23,6 +24,7 @@ type Visibility =
   | 'mutual'
   | 'circle'
   | 'personal'
+  | 'reply'
   | 'limited';
 
 const messages = defineMessages({
@@ -49,6 +51,10 @@ const messages = defineMessages({
     id: 'privacy.circle.short',
     defaultMessage: 'Circle members only',
   },
+  reply_short: {
+    id: 'privacy.reply.short',
+    defaultMessage: 'Reply',
+  },
   personal_short: {
     id: 'privacy.personal.short',
     defaultMessage: 'Yourself only',
@@ -105,6 +111,11 @@ export const VisibilityIcon: React.FC<{ visibility: Visibility }> = ({
       iconComponent: CircleIcon,
       text: intl.formatMessage(messages.circle_short),
     },
+    reply: {
+      icon: 'reply',
+      iconComponent: ReplyIcon,
+      text: intl.formatMessage(messages.reply_short),
+    },
     personal: {
       icon: 'sticky-note-o',
       iconComponent: PersonalIcon,
diff --git a/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx b/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx
index 239dec3f5b..db4dcd5f51 100644
--- a/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx
+++ b/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx
@@ -14,6 +14,7 @@ import { ReactComponent as LoginIcon } from '@material-symbols/svg-600/outlined/
 import { ReactComponent as LockIcon } from '@material-symbols/svg-600/outlined/lock.svg';
 import { ReactComponent as LockOpenIcon } from '@material-symbols/svg-600/outlined/no_encryption.svg';
 import { ReactComponent as PublicIcon } from '@material-symbols/svg-600/outlined/public.svg';
+import { ReactComponent as ReplyIcon } from '@material-symbols/svg-600/outlined/reply.svg';
 import { supportsPassiveEvents } from 'detect-passive-events';
 import Overlay from 'react-overlays/Overlay';
 
@@ -38,6 +39,8 @@ const messages = defineMessages({
   mutual_long: { id: 'privacy.mutual.long', defaultMessage: 'Mutual follows only' },
   circle_short: { id: 'privacy.circle.short', defaultMessage: 'Circle' },
   circle_long: { id: 'privacy.circle.long', defaultMessage: 'Circle members only' },
+  reply_short: { id: 'privacy.reply.short', defaultMessage: 'Reply' },
+  reply_long: { id: 'privacy.reply.long', defaultMessage: 'Reply to limited post' },
   direct_short: { id: 'privacy.direct.short', defaultMessage: 'Mentioned people only' },
   direct_long: { id: 'privacy.direct.long', defaultMessage: 'Visible for mentioned users only' },
   change_privacy: { id: 'privacy.change', defaultMessage: 'Adjust status privacy' },
@@ -166,6 +169,7 @@ class PrivacyDropdown extends PureComponent {
     value: PropTypes.string.isRequired,
     onChange: PropTypes.func.isRequired,
     noDirect: PropTypes.bool,
+    replyToLimited: PropTypes.bool,
     container: PropTypes.func,
     disabled: PropTypes.bool,
     intl: PropTypes.object.isRequired,
@@ -280,10 +284,22 @@ class PrivacyDropdown extends PureComponent {
   };
 
   render () {
-    const { value, container, disabled, intl } = this.props;
+    const { value, container, disabled, intl, replyToLimited } = this.props;
     const { open, placement } = this.state;
 
-    const valueOption = this.options.find(item => item.value === value) || this.options[0];
+    if (replyToLimited) {
+      if (!this.selectableOptions.some((op) => op.value === 'reply')) {
+        this.selectableOptions.unshift(
+          { icon: 'reply', iconComponent: ReplyIcon, value: 'reply', text: intl.formatMessage(messages.reply_short), meta: intl.formatMessage(messages.reply_long) },
+        );
+      }
+    } else {
+      if (this.selectableOptions.some((op) => op.value === 'reply')) {
+        this.selectableOptions = this.selectableOptions.filter((op) => op.value !== 'reply');
+      }
+    }
+
+    const valueOption = this.selectableOptions.find(item => item.value === value) || this.selectableOptions[0];
 
     return (
       <div ref={this.setTargetRef} onKeyDown={this.handleKeyDown}>
diff --git a/app/javascript/mastodon/features/compose/containers/privacy_dropdown_container.js b/app/javascript/mastodon/features/compose/containers/privacy_dropdown_container.js
index 6d26abf4f6..89a001a222 100644
--- a/app/javascript/mastodon/features/compose/containers/privacy_dropdown_container.js
+++ b/app/javascript/mastodon/features/compose/containers/privacy_dropdown_container.js
@@ -7,6 +7,7 @@ import PrivacyDropdown from '../components/privacy_dropdown';
 
 const mapStateToProps = state => ({
   value: state.getIn(['compose', 'privacy']),
+  replyToLimited: state.getIn(['compose', 'reply_to_limited']),
 });
 
 const mapDispatchToProps = dispatch => ({
diff --git a/app/javascript/mastodon/features/status/components/action_bar.jsx b/app/javascript/mastodon/features/status/components/action_bar.jsx
index ac7d6a8201..aefb889c41 100644
--- a/app/javascript/mastodon/features/status/components/action_bar.jsx
+++ b/app/javascript/mastodon/features/status/components/action_bar.jsx
@@ -287,7 +287,10 @@ class ActionBar extends PureComponent {
           menu.push(null);
         }
 
-        menu.push({ text: intl.formatMessage(messages.mentions), action: this.handleOpenMentions });
+        if (status.get('limited_scope') !== 'reply') {
+          menu.push({ text: intl.formatMessage(messages.mentions), action: this.handleOpenMentions });
+        }
+        
         menu.push({ text: intl.formatMessage(mutingConversation ? messages.unmuteConversation : messages.muteConversation), action: this.handleConversationMuteClick });
         menu.push(null);
         menu.push({ text: intl.formatMessage(messages.edit), action: this.handleEditClick });
diff --git a/app/javascript/mastodon/reducers/compose.js b/app/javascript/mastodon/reducers/compose.js
index 0b52bbd0a6..b4707e3321 100644
--- a/app/javascript/mastodon/reducers/compose.js
+++ b/app/javascript/mastodon/reducers/compose.js
@@ -77,6 +77,7 @@ const initialState = ImmutableMap({
   caretPosition: null,
   preselectDate: null,
   in_reply_to: null,
+  reply_to_limited: false,
   is_composing: false,
   is_submitting: false,
   is_changing_upload: false,
@@ -114,6 +115,10 @@ const initialPoll = ImmutableMap({
 });
 
 function statusToTextMentions(state, status) {
+  if (status.get('visibility_ex') === 'limited') {
+    return '';
+  }
+
   let set = ImmutableOrderedSet([]);
 
   if (status.getIn(['account', 'id']) !== me) {
@@ -144,6 +149,7 @@ function clearAll(state) {
     if (!state.get('in_reply_to')) {
       map.set('posted_on_this_session', true);
     }
+    map.set('reply_to_limited', false);
     map.set('limited_scope', null);
     map.set('id', null);
     map.set('in_reply_to', null);
@@ -411,7 +417,12 @@ export default function compose(state = initialState, action) {
       map.set('id', null);
       map.set('in_reply_to', action.status.get('id'));
       map.set('text', statusToTextMentions(state, action.status));
-      map.set('privacy', privacyPreference(action.status.get('visibility_ex'), state.get('default_privacy')));
+      map.set('reply_to_limited', action.status.get('visibility_ex') === 'limited');
+      if (action.status.get('visibility_ex') === 'limited') {
+        map.set('privacy', 'reply');
+      } else {
+        map.set('privacy', privacyPreference(action.status.get('visibility_ex'), state.get('default_privacy')));
+      }
       map.set('limited_scope', null);
       map.set('searchability', privacyPreference(action.status.get('searchability'), state.get('default_searchability')));
       map.set('focusDate', new Date());
@@ -521,7 +532,11 @@ export default function compose(state = initialState, action) {
     return state.set('tagHistory', fromJS(action.tags));
   case TIMELINE_DELETE:
     if (action.id === state.get('in_reply_to')) {
-      return state.set('in_reply_to', null);
+      if (state.get('privacy') === 'reply') {
+        return state.set('in_reply_to', null).set('privacy', 'circle');
+      } else {
+        return state.set('in_reply_to', null);
+      }
     } else if (action.id === state.get('id')) {
       return state.set('id', null);
     } else {
@@ -549,6 +564,7 @@ export default function compose(state = initialState, action) {
       map.set('text', action.raw_text || unescapeHTML(expandMentions(action.status)));
       map.set('in_reply_to', action.status.get('in_reply_to_id'));
       map.set('privacy', action.status.get('visibility_ex'));
+      map.set('reply_to_limited', action.status.get('limited_scope') === 'reply');
       map.set('limited_scope', null);
       map.set('media_attachments', action.status.get('media_attachments').map((media) => media.set('unattached', true)));
       map.set('focusDate', new Date());
@@ -583,8 +599,9 @@ export default function compose(state = initialState, action) {
       if (action.status.get('visibility_ex') !== 'limited') {
         map.set('privacy', action.status.get('visibility_ex'));
       } else {
-        map.set('privacy', action.status.get('limited_scope') === 'mutual' ? 'mutual' : 'circle');
+        map.set('privacy', action.status.get('limited_scope') || 'circle');
       }
+      map.set('reply_to_limited', action.status.get('limited_scope') === 'reply');
       map.set('limited_scope', action.status.get('limited_scope'));
       map.set('media_attachments', action.status.get('media_attachments'));
       map.set('focusDate', new Date());
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 204899fa39..57212acb40 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -93,6 +93,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
 
     resolve_thread(@status)
     fetch_replies(@status)
+    process_conversation! if @status.limited_visibility?
     process_references!
     distribute
     forward_for_reply
@@ -132,7 +133,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
       limited_scope: @status_parser.limited_scope,
       searchability: @status_parser.searchability,
       thread: replied_to_status,
-      conversation: conversation_from_uri(@object['conversation']),
+      conversation: conversation_from_activity,
       media_attachment_ids: process_attachments.take(MediaAttachment::ACTIVITYPUB_STATUS_ATTACHMENT_MAX).map(&:id),
       poll: process_poll,
     }
@@ -184,6 +185,10 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     @silenced_account_ids = @mentions.map(&:account_id) - accounts_in_audience.map(&:id)
   end
 
+  def account_representative
+    accounts_in_audience.detect(&:local?) || Account.representative
+  end
+
   def postprocess_audience_and_deliver
     return if @status.mentions.find_by(account_id: @options[:delivered_to_account_id])
 
@@ -373,6 +378,10 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     ActivityPub::FetchRepliesWorker.perform_async(status.id, uri, { 'request_id' => @options[:request_id] }) unless uri.nil?
   end
 
+  def conversation_from_activity
+    conversation_from_context(@object['context']) || conversation_from_uri(@object['conversation'])
+  end
+
   def conversation_from_uri(uri)
     return nil if uri.nil?
     return Conversation.find_by(id: OStatus::TagManager.instance.unique_tag_to_local_id(uri, 'Conversation')) if OStatus::TagManager.instance.local_id?(uri)
@@ -384,6 +393,26 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     end
   end
 
+  def conversation_from_context(uri)
+    return nil if uri.nil?
+    return Conversation.find_by(id: ActivityPub::TagManager.instance.uri_to_local_id(uri)) if ActivityPub::TagManager.instance.local_uri?(uri)
+
+    begin
+      conversation = Conversation.find_or_create_by!(uri: uri)
+
+      json = fetch_resource_without_id_validation(uri, account_representative)
+      return conversation if json.nil? || json['type'] != 'Group'
+      return conversation if json['inbox'].blank? || json['inbox'] == conversation.inbox_url
+
+      conversation.update!(inbox_url: json['inbox'])
+      conversation
+    rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotUnique
+      retry
+    rescue Mastodon::UnexpectedResponseError
+      Conversation.find_or_create_by!(uri: uri)
+    end
+  end
+
   def replied_to_status
     return @replied_to_status if defined?(@replied_to_status)
 
@@ -483,6 +512,16 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     ActivityPub::RawDistributionWorker.perform_async(Oj.dump(@json), replied_to_status.account_id, [@account.preferred_inbox_url])
   end
 
+  def process_conversation!
+    return unless @status.conversation.present? && @status.conversation.local?
+
+    ProcessConversationService.new.call(@status)
+
+    return if @json['signature'].blank?
+
+    ActivityPub::ForwardConversationWorker.perform_async(Oj.dump(@json), @status.id, false)
+  end
+
   def increment_voters_count!
     poll = replied_to_status.preloadable_poll
 
diff --git a/app/lib/activitypub/activity/delete.rb b/app/lib/activitypub/activity/delete.rb
index f401714430..4f02d83427 100644
--- a/app/lib/activitypub/activity/delete.rb
+++ b/app/lib/activitypub/activity/delete.rb
@@ -40,10 +40,17 @@ class ActivityPub::Activity::Delete < ActivityPub::Activity
       return if @status.nil?
 
       forwarder.forward! if forwarder.forwardable?
+      forward_for_conversation
       delete_now!
     end
   end
 
+  def forward_for_conversation
+    return unless @status.conversation.present? && @status.conversation.local? && @json['signature'].present?
+
+    ActivityPub::ForwardConversationWorker.perform_async(Oj.dump(@json), @status.id, true)
+  end
+
   def delete_friend
     friend = FriendDomain.find_by(domain: @account.domain)
     friend&.destroy
diff --git a/app/lib/activitypub/activity/update.rb b/app/lib/activitypub/activity/update.rb
index 973706f595..1e98eecd58 100644
--- a/app/lib/activitypub/activity/update.rb
+++ b/app/lib/activitypub/activity/update.rb
@@ -31,5 +31,13 @@ class ActivityPub::Activity::Update < ActivityPub::Activity
     return if @status.nil?
 
     ActivityPub::ProcessStatusUpdateService.new.call(@status, @json, @object, request_id: @options[:request_id])
+
+    forward_for_conversation
+  end
+
+  def forward_for_conversation
+    return unless @status.conversation.present? && @status.conversation.local? && @json['signature'].present?
+
+    ActivityPub::ForwardConversationWorker.perform_async(Oj.dump(@json), @status.id, true)
   end
 end
diff --git a/app/lib/activitypub/parser/status_parser.rb b/app/lib/activitypub/parser/status_parser.rb
index 4cd48d03f6..059860979c 100644
--- a/app/lib/activitypub/parser/status_parser.rb
+++ b/app/lib/activitypub/parser/status_parser.rb
@@ -105,6 +105,8 @@ class ActivityPub::Parser::StatusParser
       :mutual
     when 'Circle'
       :circle
+    when 'Reply'
+      :reply
     else
       :none
     end
diff --git a/app/lib/activitypub/tag_manager.rb b/app/lib/activitypub/tag_manager.rb
index a1817b9607..33829e8894 100644
--- a/app/lib/activitypub/tag_manager.rb
+++ b/app/lib/activitypub/tag_manager.rb
@@ -49,6 +49,8 @@ class ActivityPub::TagManager
       emoji_url(target)
     when :emoji_reaction
       emoji_reaction_url(target)
+    when :conversation
+      context_url(target)
     when :flag
       target.uri
     end
@@ -119,7 +121,8 @@ class ActivityPub::TagManager
         end.compact
       end
     when 'limited'
-      ['kmyblue:Limited'] # to avoid Fedibird personal visibility
+      # do not empty array to avoid Fedibird personal visibility
+      status.conversation.nil? ? ['kmyblue:Limited'] : [context_url(status.conversation)]
     end
   end
 
@@ -225,10 +228,15 @@ class ActivityPub::TagManager
   end
 
   def limited_scope(status)
-    if status.mutual_limited?
+    case status.limited_scope
+    when 'mutual'
       'Mutual'
+    when 'circle'
+      'Circle'
+    when 'reply'
+      'Reply'
     else
-      status.circle_limited? ? 'Circle' : ''
+      ''
     end
   end
 
@@ -250,8 +258,6 @@ class ActivityPub::TagManager
         [COLLECTIONS[:public]]
       when 'private'
         [account_followers_url(status.account)]
-      when 'direct'
-        status.conversation_id.present? ? [uri_for(status.conversation)] : []
       when 'limited'
         ['as:Limited', 'kmyblue:Limited']
       else
@@ -271,7 +277,7 @@ class ActivityPub::TagManager
     case account.compute_searchability_activitypub
     when 'public'
       [COLLECTIONS[:public]]
-    when 'private', 'direct'
+    when 'private'
       [account_followers_url(account)]
     when 'limited'
       ['as:Limited', 'kmyblue:Limited']
diff --git a/app/lib/feed_manager.rb b/app/lib/feed_manager.rb
index de4944c3ec..6d55a44e4a 100644
--- a/app/lib/feed_manager.rb
+++ b/app/lib/feed_manager.rb
@@ -409,9 +409,9 @@ class FeedManager
   # @param [Integer] receiver_id
   # @param [Hash] crutches
   # @return [Boolean]
-  def filter_from_home?(status, receiver_id, crutches, timeline_type = :home, stl_home: false)
+  def filter_from_home?(status, receiver_id, crutches, timeline_type = :home, stl_home: false) # rubocop:disable Metrics/PerceivedComplexity
     return false if receiver_id == status.account_id
-    return true  if status.reply? && (status.in_reply_to_id.nil? || status.in_reply_to_account_id.nil?)
+    return true  if status.reply? && (status.in_reply_to_id.nil? || status.in_reply_to_account_id.nil?) && !(timeline_type == :home && status.limited_visibility?)
     return true if (timeline_type != :list || stl_home) && (crutches[:exclusive_list_users][status.account_id].present? || crutches[:exclusive_antenna_users][status.account_id].present?)
     return true if crutches[:languages][status.account_id].present? && status.language.present? && !crutches[:languages][status.account_id].include?(status.language)
 
@@ -426,10 +426,11 @@ class FeedManager
     return true if check_for_blocks.any? { |target_account_id| crutches[:blocking][target_account_id] || crutches[:muting][target_account_id] }
     return true if crutches[:blocked_by][status.account_id]
 
-    if status.reply? && !status.in_reply_to_account_id.nil?                                                                      # Filter out if it's a reply
-      should_filter   = !crutches[:following][status.in_reply_to_account_id]                                                     # and I'm not following the person it's a reply to
-      should_filter &&= receiver_id != status.in_reply_to_account_id                                                             # and it's not a reply to me
-      should_filter &&= status.account_id != status.in_reply_to_account_id                                                       # and it's not a self-reply
+    if status.reply? && (!status.in_reply_to_account_id.nil? || (status.thread.present? && status.limited_visibility?)) # Filter out if it's a reply
+      account_id      = status.in_reply_to_account_id || status.thread.account_id
+      should_filter   = !crutches[:following][account_id]                                                     # and I'm not following the person it's a reply to
+      should_filter &&= receiver_id != account_id                                                             # and it's not a reply to me
+      should_filter &&= status.account_id != account_id                                                       # and it's not a self-reply
 
       return !!should_filter
     elsif status.reblog?                                                                                                         # Filter out a reblog
@@ -607,7 +608,10 @@ class FeedManager
     lists = List.where(account_id: receiver_id, exclusive: true)
     antennas = Antenna.where(list: lists, insert_feeds: true)
 
-    crutches[:following]            = Follow.where(account_id: receiver_id, target_account_id: statuses.filter_map(&:in_reply_to_account_id)).pluck(:target_account_id).index_with(true)
+    replied_accounts  = statuses.filter_map(&:in_reply_to_account_id)
+    replied_accounts += statuses.filter { |status| status.limited_visibility? && status.thread.present? }.map { |status| status.thread.account_id }
+
+    crutches[:following]            = Follow.where(account_id: receiver_id, target_account_id: replied_accounts).pluck(:target_account_id).index_with(true)
     crutches[:languages]            = Follow.where(account_id: receiver_id, target_account_id: statuses.map(&:account_id)).pluck(:target_account_id, :languages).to_h
     crutches[:hiding_reblogs]       = Follow.where(account_id: receiver_id, target_account_id: statuses.filter_map { |s| s.account_id if s.reblog? }, show_reblogs: false).pluck(:target_account_id).index_with(true)
     crutches[:blocking]             = Block.where(account_id: receiver_id, target_account_id: check_for_blocks).pluck(:target_account_id).index_with(true)
diff --git a/app/lib/status_reach_finder.rb b/app/lib/status_reach_finder.rb
index 62634f36c1..f588e4374d 100644
--- a/app/lib/status_reach_finder.rb
+++ b/app/lib/status_reach_finder.rb
@@ -51,22 +51,18 @@ class StatusReachFinder
   end
 
   def reached_account_inboxes_for_misskey
-    if @status.reblog?
+    if @status.reblog? || @status.limited_visibility?
       []
-    elsif @status.limited_visibility?
-      Account.where(id: mentioned_account_ids).where(domain: banned_domains_for_misskey).inboxes
     else
-      Account.where(id: reached_account_ids).where(domain: banned_domains_for_misskey - friend_domains).inboxes
+      Account.where(id: reached_account_ids, domain: banned_domains_for_misskey - friend_domains).inboxes
     end
   end
 
   def reached_account_inboxes_for_friend
-    if @status.reblog?
+    if @status.reblog? || @status.limited_visibility?
       []
-    elsif @status.limited_visibility?
-      Account.where(id: mentioned_account_ids).where.not(domain: banned_domains).inboxes
     else
-      Account.where(id: reached_account_ids, domain: friend_domains).where.not(domain: banned_domains - friend_domains).inboxes
+      Account.where(id: reached_account_ids, domain: friend_domains).inboxes
     end
   end
 
diff --git a/app/models/conversation.rb b/app/models/conversation.rb
index 5de2599627..90fdd8143b 100644
--- a/app/models/conversation.rb
+++ b/app/models/conversation.rb
@@ -4,18 +4,25 @@
 #
 # Table name: conversations
 #
-#  id         :bigint(8)        not null, primary key
-#  uri        :string
-#  created_at :datetime         not null
-#  updated_at :datetime         not null
+#  id                 :bigint(8)        not null, primary key
+#  uri                :string
+#  created_at         :datetime         not null
+#  updated_at         :datetime         not null
+#  inbox_url          :string
+#  ancestor_status_id :bigint(8)
 #
 
 class Conversation < ApplicationRecord
   validates :uri, uniqueness: true, if: :uri?
 
   has_many :statuses
+  belongs_to :ancestor_status, class_name: 'Status', inverse_of: :owned_conversation, optional: true
 
   def local?
     uri.nil?
   end
+
+  def object_type
+    :conversation
+  end
 end
diff --git a/app/models/status.rb b/app/models/status.rb
index 069a1b423e..841c2b5b02 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -59,13 +59,14 @@ class Status < ApplicationRecord
 
   enum visibility: { public: 0, unlisted: 1, private: 2, direct: 3, limited: 4, public_unlisted: 10, login: 11 }, _suffix: :visibility
   enum searchability: { public: 0, private: 1, direct: 2, limited: 3, unsupported: 4, public_unlisted: 10 }, _suffix: :searchability
-  enum limited_scope: { none: 0, mutual: 1, circle: 2, personal: 3 }, _suffix: :limited
+  enum limited_scope: { none: 0, mutual: 1, circle: 2, personal: 3, reply: 4 }, _suffix: :limited
 
   belongs_to :application, class_name: 'Doorkeeper::Application', optional: true
 
   belongs_to :account, inverse_of: :statuses
   belongs_to :in_reply_to_account, class_name: 'Account', optional: true
   belongs_to :conversation, optional: true
+  has_one :owned_conversation, class_name: 'Conversation', foreign_key: 'ancestor_status_id', dependent: :nullify, inverse_of: false
   belongs_to :preloadable_poll, class_name: 'Poll', foreign_key: 'poll_id', optional: true, inverse_of: false
 
   belongs_to :thread, foreign_key: 'in_reply_to_id', class_name: 'Status', inverse_of: :replies, optional: true
@@ -83,6 +84,7 @@ class Status < ApplicationRecord
   has_many :mentions, dependent: :destroy, inverse_of: :status
   has_many :mentioned_accounts, through: :mentions, source: :account, class_name: 'Account'
   has_many :active_mentions, -> { active }, class_name: 'Mention', inverse_of: :status
+  has_many :silent_mentions, -> { silent }, class_name: 'Mention', inverse_of: :status
   has_many :media_attachments, dependent: :nullify
   has_many :reference_objects, class_name: 'StatusReference', inverse_of: :status, dependent: :destroy
   has_many :references, through: :reference_objects, class_name: 'Status', source: :target_status
@@ -658,11 +660,16 @@ class Status < ApplicationRecord
 
     self.reply = !(in_reply_to_id.nil? && thread.nil?) unless reply
 
-    if reply? && !thread.nil?
+    if reply? && !thread.nil? && (!limited_visibility? || none_limited? || reply_limited?)
       self.in_reply_to_account_id = carried_over_reply_to_account_id
       self.conversation_id        = thread.conversation_id if conversation_id.nil?
     elsif conversation_id.nil?
-      self.conversation = Conversation.new
+      if local?
+        self.owned_conversation = Conversation.new
+        self.conversation = owned_conversation
+      else
+        self.conversation = Conversation.new
+      end
     end
   end
 
diff --git a/app/policies/status_policy.rb b/app/policies/status_policy.rb
index 41d242e088..e57c685464 100644
--- a/app/policies/status_policy.rb
+++ b/app/policies/status_policy.rb
@@ -25,7 +25,7 @@ class StatusPolicy < ApplicationPolicy
   end
 
   def show_mentioned_users?
-    owned?
+    record.limited_visibility? ? owned_conversation? : owned?
   end
 
   def reblog?
@@ -64,6 +64,11 @@ class StatusPolicy < ApplicationPolicy
     author.id == current_account&.id
   end
 
+  def owned_conversation?
+    record.conversation&.local? &&
+      (record.conversation.ancestor_status.nil? ? owned? : record.conversation.ancestor_status.account_id == current_account&.id)
+  end
+
   def private?
     record.private_visibility?
   end
diff --git a/app/serializers/activitypub/context_serializer.rb b/app/serializers/activitypub/context_serializer.rb
new file mode 100644
index 0000000000..a6a0bbb07f
--- /dev/null
+++ b/app/serializers/activitypub/context_serializer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class ActivityPub::ContextSerializer < ActivityPub::Serializer
+  include RoutingHelper
+
+  attributes :id, :type, :inbox
+
+  def id
+    ActivityPub::TagManager.instance.uri_for(object)
+  end
+
+  def type
+    'Group'
+  end
+
+  def inbox
+    return '' if object.ancestor_status.nil?
+
+    account_inbox_url(object.ancestor_status.account)
+  end
+end
diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index 3c89c7b632..6cfbc97f2f 100644
--- a/app/serializers/activitypub/note_serializer.rb
+++ b/app/serializers/activitypub/note_serializer.rb
@@ -9,11 +9,12 @@ class ActivityPub::NoteSerializer < ActivityPub::Serializer
              :in_reply_to, :published, :url,
              :attributed_to, :to, :cc, :sensitive,
              :atom_uri, :in_reply_to_atom_uri,
-             :conversation, :searchable_by, :limited_scope
+             :conversation, :searchable_by, :context
 
   attribute :content
   attribute :content_map, if: :language?
   attribute :updated, if: :edited?
+  attribute :limited_scope, if: :limited_visibility?
 
   attribute :quote_uri, if: :quote?
   attribute :misskey_quote, key: :_misskey_quote, if: :quote?
@@ -52,6 +53,10 @@ class ActivityPub::NoteSerializer < ActivityPub::Serializer
     { object.language => content }
   end
 
+  def context
+    ActivityPub::TagManager.instance.uri_for(object.conversation)
+  end
+
   def replies
     replies = object.self_replies(5).pluck(:id, :uri)
     last_id = replies.last&.first
@@ -88,6 +93,8 @@ class ActivityPub::NoteSerializer < ActivityPub::Serializer
     object.language.present?
   end
 
+  delegate :limited_visibility?, to: :object
+
   delegate :edited?, to: :object
 
   def in_reply_to
diff --git a/app/services/concerns/payloadable.rb b/app/services/concerns/payloadable.rb
index b0bab9a081..113b389fac 100644
--- a/app/services/concerns/payloadable.rb
+++ b/app/services/concerns/payloadable.rb
@@ -14,11 +14,12 @@ module Payloadable
     signer      = options.delete(:signer)
     sign_with   = options.delete(:sign_with)
     always_sign = options.delete(:always_sign)
+    always_sign_unsafe = options.delete(:always_sign_unsafe)
     payload     = ActiveModelSerializers::SerializableResource.new(record, options.merge(serializer: serializer, adapter: ActivityPub::Adapter)).as_json
     object      = record.respond_to?(:virtual_object) ? record.virtual_object : record
     bearcap     = object.is_a?(String) && record.respond_to?(:type) && (record.type == 'Create' || record.type == 'Update')
 
-    if ((object.respond_to?(:sign?) && object.sign?) && signer && (always_sign || signing_enabled?)) || bearcap
+    if ((object.respond_to?(:sign?) && object.sign?) && signer && (always_sign || signing_enabled?)) || bearcap || (signer && always_sign_unsafe)
       ActivityPub::LinkedDataSignature.new(payload).sign!(signer, sign_with: sign_with)
     else
       payload
diff --git a/app/services/fan_out_on_write_service.rb b/app/services/fan_out_on_write_service.rb
index 1455eed2ff..41515fa59b 100644
--- a/app/services/fan_out_on_write_service.rb
+++ b/app/services/fan_out_on_write_service.rb
@@ -46,6 +46,7 @@ class FanOutOnWriteService < BaseService
 
     unless @options[:skip_notifications]
       notify_mentioned_accounts!
+      notify_for_conversation! if @status.limited_visibility?
       notify_about_update! if update?
     end
 
@@ -93,6 +94,17 @@ class FanOutOnWriteService < BaseService
     end
   end
 
+  def notify_for_conversation!
+    return if @status.conversation.nil?
+
+    account_ids = @status.conversation.statuses.pluck(:account_id).uniq.reject { |account_id| account_id == @status.account_id }
+    @status.silent_mentions.where(account_id: account_ids).joins(:account).merge(Account.local).select(:id, :account_id).reorder(nil).find_in_batches do |mentions|
+      LocalNotificationWorker.push_bulk(mentions) do |mention|
+        [mention.account_id, mention.id, 'Mention', 'mention']
+      end
+    end
+  end
+
   def notify_about_update!
     @status.reblogged_by_accounts.or(@status.quoted_by_accounts).merge(Account.local).select(:id).reorder(nil).find_in_batches do |accounts|
       LocalNotificationWorker.push_bulk(accounts) do |account|
diff --git a/app/services/post_status_service.rb b/app/services/post_status_service.rb
index cec0737273..b8c5d27782 100644
--- a/app/services/post_status_service.rb
+++ b/app/services/post_status_service.rb
@@ -75,11 +75,10 @@ class PostStatusService < BaseService
                      end) || @options[:spoiler_text].present?
     @text         = @options.delete(:spoiler_text) if @text.blank? && @options[:spoiler_text].present?
     @visibility   = @options[:visibility]&.to_sym || @account.user&.setting_default_privacy&.to_sym
-    @visibility   = :direct if @in_reply_to&.limited_visibility?
-    @visibility   = :limited if %w(mutual circle).include?(@options[:visibility])
-    @visibility   = :unlisted if (@visibility&.to_sym == :public || @visibility&.to_sym == :public_unlisted || @visibility&.to_sym == :login) && @account.silenced?
-    @visibility   = :public_unlisted if @visibility&.to_sym == :public && !@options[:force_visibility] && !@options[:application]&.superapp && @account.user&.setting_public_post_to_unlisted && Setting.enable_public_unlisted_visibility
-    @limited_scope = @options[:visibility]&.to_sym if @visibility == :limited
+    @visibility   = :limited if %w(mutual circle reply).include?(@options[:visibility])
+    @visibility   = :unlisted if (@visibility == :public || @visibility == :public_unlisted || @visibility == :login) && @account.silenced?
+    @visibility   = :public_unlisted if @visibility == :public && !@options[:force_visibility] && !@options[:application]&.superapp && @account.user&.setting_public_post_to_unlisted && Setting.enable_public_unlisted_visibility
+    @limited_scope = @options[:visibility]&.to_sym if @visibility == :limited && @options[:visibility] != 'limited'
     @searchability = searchability
     @searchability = :private if @account.silenced? && %i(public public_unlisted).include?(@searchability&.to_sym)
     @markdown     = @options[:markdown] || false
@@ -88,6 +87,11 @@ class PostStatusService < BaseService
     @reference_ids = (@options[:status_reference_ids] || []).map(&:to_i).filter(&:positive?)
     raise ArgumentError if !Setting.enable_public_unlisted_visibility && @visibility == :public_unlisted
 
+    if @in_reply_to.present? && ((@options[:visibility] == 'limited' && @options[:circle_id].nil?) || @limited_scope == :reply)
+      @visibility = :limited
+      @limited_scope = :reply
+    end
+
     load_circle
     overwrite_dtl_post
     process_sensitive_words
@@ -96,8 +100,9 @@ class PostStatusService < BaseService
   end
 
   def load_circle
-    raise ArgumentError if @options[:visibility] == 'limited' && @options[:circle_id].nil?
-    return unless @options[:visibility] == 'circle' || (@options[:visibility] == 'limited' && @options[:circle_id].present?)
+    return if @visibility == :limited && @limited_scope == :reply && @in_reply_to.present?
+    return unless %w(circle limited reply).include?(@options[:visibility])
+    raise ArgumentError if @options[:circle_id].nil?
 
     @circle = @options[:circle_id].present? && Circle.find(@options[:circle_id])
     @limited_scope = :circle
@@ -148,7 +153,7 @@ class PostStatusService < BaseService
     safeguard_mentions!(@status)
     validate_status_mentions!
 
-    @status.limited_scope = :personal if @status.limited_visibility? && !process_mentions_service.mentions?
+    @status.limited_scope = :personal if @status.limited_visibility? && !@status.reply_limited? && !process_mentions_service.mentions?
 
     UpdateStatusExpirationService.new.call(@status)
 
@@ -196,6 +201,7 @@ class PostStatusService < BaseService
 
     process_hashtags_service.call(@status)
     Trends.tags.register(@status)
+    ProcessConversationService.new.call(@status) if @status.limited_visibility? && @status.reply_limited?
     ProcessReferencesService.call_service(@status, @reference_ids, [])
     LinkCrawlWorker.perform_async(@status.id)
     DistributionWorker.perform_async(@status.id)
diff --git a/app/services/process_conversation_service.rb b/app/services/process_conversation_service.rb
new file mode 100644
index 0000000000..7facbb5a42
--- /dev/null
+++ b/app/services/process_conversation_service.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+class ProcessConversationService < BaseService
+  def call(status)
+    @status = status
+
+    return if !@status.limited_visibility? || @status.conversation.nil?
+
+    duplicate_reply!
+  end
+
+  private
+
+  def thread
+    @thread ||= @status.thread || @status.conversation.ancestor_status
+  end
+
+  def duplicate_reply!
+    return unless @status.conversation.local?
+    return if !@status.reply? || thread.nil?
+    return if thread.conversation_id != @status.conversation_id
+
+    mentioned_account_ids = @status.mentions.pluck(:account_id)
+
+    thread.mentioned_accounts.find_each do |account|
+      @status.mentions << @status.mentions.new(silent: true, account: account) unless mentioned_account_ids.include?(account.id)
+      mentioned_account_ids << account.id
+    end
+    @status.mentions << @status.mentions.new(silent: true, account: thread.account) unless mentioned_account_ids.include?(thread.account.id)
+
+    @status.save!
+  end
+end
diff --git a/app/services/remove_status_service.rb b/app/services/remove_status_service.rb
index ada2fde1be..448ae614f5 100644
--- a/app/services/remove_status_service.rb
+++ b/app/services/remove_status_service.rb
@@ -106,6 +106,8 @@ class RemoveStatusService < BaseService
     # the author and wouldn't normally receive the delete
     # notification - so here, we explicitly send it to them
 
+    return remove_from_conversation if @status.limited_visibility? && @status.conversation.present? && !@status.conversation.local?
+
     status_reach_finder = StatusReachFinder.new(@status, unsafe: true)
 
     ActivityPub::DeliveryWorker.push_bulk(status_reach_finder.all_inboxes, limit: 1_000) do |inbox_url|
@@ -113,8 +115,14 @@ class RemoveStatusService < BaseService
     end
   end
 
+  def remove_from_conversation
+    return if @status.conversation.nil? || @status.conversation.inbox_url.blank?
+
+    ActivityPub::DeliveryWorker.perform_async(signed_activity_json, @account.id, @status.conversation.inbox_url)
+  end
+
   def signed_activity_json
-    @signed_activity_json ||= Oj.dump(serialize_payload(@status, @status.reblog? ? ActivityPub::UndoAnnounceSerializer : ActivityPub::DeleteSerializer, signer: @account, always_sign: true))
+    @signed_activity_json ||= Oj.dump(serialize_payload(@status, @status.reblog? ? ActivityPub::UndoAnnounceSerializer : ActivityPub::DeleteSerializer, signer: @account, always_sign_unsafe: @status.limited_visibility?))
   end
 
   def remove_reblogs
diff --git a/app/workers/activitypub/distribution_worker.rb b/app/workers/activitypub/distribution_worker.rb
index f8f80864a4..260334760e 100644
--- a/app/workers/activitypub/distribution_worker.rb
+++ b/app/workers/activitypub/distribution_worker.rb
@@ -19,11 +19,26 @@ class ActivityPub::DistributionWorker < ActivityPub::RawDistributionWorker
   protected
 
   def distribute_limited!
+    if @status.reply? && @status.conversation.present? && !@status.conversation.local?
+      distribute_conversation!
+    else
+      distribute_limited_mentions!
+    end
+  end
+
+  def distribute_limited_mentions!
     ActivityPub::DeliveryWorker.push_bulk(inboxes_for_limited, limit: 1_000) do |inbox_url|
       [payload, @account.id, inbox_url, options]
     end
   end
 
+  def distribute_conversation!
+    inbox_url = @status.conversation.inbox_url
+    return if inbox_url.blank?
+
+    ActivityPub::DeliveryWorker.perform_async(payload, @account.id, inbox_url, options)
+  end
+
   def inboxes
     @inboxes ||= status_reach_finder.inboxes
   end
@@ -45,7 +60,7 @@ class ActivityPub::DistributionWorker < ActivityPub::RawDistributionWorker
   end
 
   def payload
-    @payload ||= Oj.dump(serialize_payload(activity, ActivityPub::ActivitySerializer, signer: @account))
+    @payload ||= Oj.dump(serialize_payload(activity, ActivityPub::ActivitySerializer, signer: @account, always_sign_unsafe: always_sign))
   end
 
   def payload_for_misskey
@@ -53,7 +68,7 @@ class ActivityPub::DistributionWorker < ActivityPub::RawDistributionWorker
   end
 
   def payload_for_friend
-    @payload_for_friend ||= Oj.dump(serialize_payload(activity_for_friend, ActivityPub::ActivityForFriendSerializer, signer: @account))
+    @payload_for_friend ||= Oj.dump(serialize_payload(activity_for_friend, ActivityPub::ActivityForFriendSerializer, signer: @account, always_sign_unsafe: always_sign))
   end
 
   def activity
@@ -68,6 +83,10 @@ class ActivityPub::DistributionWorker < ActivityPub::RawDistributionWorker
     ActivityPub::ActivityPresenter.from_status(@status, for_friend: true)
   end
 
+  def always_sign
+    false
+  end
+
   def options
     { 'synchronize_followers' => @status.private_visibility? }
   end
diff --git a/app/workers/activitypub/forward_conversation_worker.rb b/app/workers/activitypub/forward_conversation_worker.rb
new file mode 100644
index 0000000000..8e0bd59767
--- /dev/null
+++ b/app/workers/activitypub/forward_conversation_worker.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+class ActivityPub::ForwardConversationWorker
+  include Sidekiq::Worker
+
+  def perform(payload, status_id, shared_inbox)
+    @status  = Status.find(status_id)
+    @payload = payload
+    @shared_inbox = shared_inbox
+
+    return unless @status.conversation.present? && @status.conversation.local? && @status.conversation.ancestor_status.present?
+    return unless @status.limited_visibility?
+
+    @account = @status.conversation.ancestor_status.account
+
+    distribute_limited_mentions!
+  rescue ActiveRecord::RecordNotFound
+    true
+  end
+
+  protected
+
+  def distribute_limited_mentions!
+    ActivityPub::DeliveryWorker.push_bulk(inboxes_for_limited, limit: 1_000) do |inbox_url|
+      [payload, @account.id, inbox_url, options]
+    end
+  end
+
+  def inboxes_for_limited
+    if @shared_inbox
+      inbox_accounts.inboxes
+    else
+      DeliveryFailureTracker.without_unavailable(inbox_accounts.pluck(:inbox_url).compact_blank.uniq)
+    end
+  end
+
+  def inbox_accounts
+    Account.remote.merge(@status.mentioned_accounts)
+  end
+
+  def options
+    { 'synchronize_followers' => @status.private_visibility? }
+  end
+
+  attr_reader :payload
+end
diff --git a/app/workers/activitypub/status_update_distribution_worker.rb b/app/workers/activitypub/status_update_distribution_worker.rb
index 49ac509761..2c7922e419 100644
--- a/app/workers/activitypub/status_update_distribution_worker.rb
+++ b/app/workers/activitypub/status_update_distribution_worker.rb
@@ -8,13 +8,21 @@ class ActivityPub::StatusUpdateDistributionWorker < ActivityPub::DistributionWor
     @status  = Status.find(status_id)
     @account = @status.account
 
-    distribute!
+    if @status.limited_visibility?
+      distribute_limited!
+    else
+      distribute!
+    end
   rescue ActiveRecord::RecordNotFound
     true
   end
 
   protected
 
+  def inboxes_for_limited
+    @inboxes_for_limited ||= @status.mentioned_accounts.inboxes
+  end
+
   def build_activity(for_misskey: false, for_friend: false)
     ActivityPub::ActivityPresenter.new(
       id: [ActivityPub::TagManager.instance.uri_for(@status), '#updates/', @status.edited_at.to_i].join,
@@ -38,4 +46,8 @@ class ActivityPub::StatusUpdateDistributionWorker < ActivityPub::DistributionWor
   def activity_for_friend
     build_activity(for_friend: true)
   end
+
+  def always_sign
+    @status.limited_visibility?
+  end
 end
diff --git a/config/routes.rb b/config/routes.rb
index d96827d0d4..374a4a83d3 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -142,6 +142,7 @@ Rails.application.routes.draw do
   end
 
   resource :inbox, only: [:create], module: :activitypub
+  resources :contexts, only: [:show], module: :activitypub
 
   get '/:encoded_at(*path)', to: redirect("/@%{path}"), constraints: { encoded_at: /%40/ }
 
diff --git a/db/migrate/20231115001356_add_inbox_url_to_conversations.rb b/db/migrate/20231115001356_add_inbox_url_to_conversations.rb
new file mode 100644
index 0000000000..460d61fc45
--- /dev/null
+++ b/db/migrate/20231115001356_add_inbox_url_to_conversations.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require Rails.root.join('lib', 'mastodon', 'migration_helpers')
+
+class AddInboxURLToConversations < ActiveRecord::Migration[7.1]
+  include Mastodon::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  def change
+    safety_assured do
+      add_column_with_default :conversations, :inbox_url, :string, default: nil, allow_null: true
+      add_column_with_default :conversations, :ancestor_status_id, :bigint, default: nil, allow_null: true
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 0a26fcda71..20702a451c 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[7.1].define(version: 2023_11_05_225839) do
+ActiveRecord::Schema[7.1].define(version: 2023_11_15_001356) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -475,6 +475,8 @@ ActiveRecord::Schema[7.1].define(version: 2023_11_05_225839) do
     t.string "uri"
     t.datetime "created_at", precision: nil, null: false
     t.datetime "updated_at", precision: nil, null: false
+    t.string "inbox_url"
+    t.bigint "ancestor_status_id"
     t.index ["uri"], name: "index_conversations_on_uri", unique: true, opclass: :text_pattern_ops, where: "(uri IS NOT NULL)"
   end
 
diff --git a/spec/lib/activitypub/activity/create_spec.rb b/spec/lib/activitypub/activity/create_spec.rb
index a10881e600..ed196d1a1a 100644
--- a/spec/lib/activitypub/activity/create_spec.rb
+++ b/spec/lib/activitypub/activity/create_spec.rb
@@ -16,12 +16,22 @@ RSpec.describe ActivityPub::Activity::Create do
     }.with_indifferent_access
   end
 
+  let(:conversation) do
+    {
+      id: 'http://example.com/conversation',
+      type: 'Group',
+      inbox: 'http://example.com/actor/inbox',
+    }.with_indifferent_access
+  end
+
   before do
     sender.update(uri: ActivityPub::TagManager.instance.uri_for(sender))
 
     stub_request(:get, 'http://example.com/attachment.png').to_return(request_fixture('avatar.txt'))
     stub_request(:get, 'http://example.com/emoji.png').to_return(body: attachment_fixture('emojo.png'))
     stub_request(:get, 'http://example.com/emojib.png').to_return(body: attachment_fixture('emojo.png'), headers: { 'Content-Type' => 'application/octet-stream' })
+    stub_request(:get, 'http://example.com/conversation').to_return(body: Oj.dump(conversation))
+    stub_request(:get, 'http://example.com/invalid-conversation').to_return(status: 404)
   end
 
   describe 'processing posts received out of order', :sidekiq_fake do
@@ -122,11 +132,12 @@ RSpec.describe ActivityPub::Activity::Create do
 
   describe '#perform' do
     context 'when fetching' do
-      subject { described_class.new(json, sender) }
+      subject { delivered_to_account_id ? described_class.new(json, sender, delivered_to_account_id: delivered_to_account_id) : described_class.new(json, sender) }
 
       let(:sender_software) { 'mastodon' }
       let(:custom_before) { false }
       let(:active_friend) { false }
+      let(:delivered_to_account_id) { nil }
 
       before do
         Fabricate(:instance_info, domain: 'example.com', software: sender_software)
@@ -932,6 +943,259 @@ RSpec.describe ActivityPub::Activity::Create do
         end
       end
 
+      context 'with a context' do
+        let(:object_json) do
+          {
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+            type: 'Note',
+            content: 'Lorem ipsum',
+            context: 'http://example.com/conversation',
+          }
+        end
+
+        it 'creates status' do
+          status = sender.statuses.first
+
+          expect(status).to_not be_nil
+          expect(status.conversation).to_not be_nil
+          expect(status.conversation.uri).to eq 'http://example.com/conversation'
+          expect(status.conversation.inbox_url).to eq 'http://example.com/actor/inbox'
+        end
+
+        context 'when existing' do
+          let(:custom_before) { true }
+          let!(:existing) { Fabricate(:conversation, uri: 'http://example.com/conversation', inbox_url: 'http://example.com/actor/invalid') }
+
+          before do
+            subject.perform
+          end
+
+          it 'creates status' do
+            status = sender.statuses.first
+
+            expect(status).to_not be_nil
+            expect(status.conversation).to_not be_nil
+            expect(status.conversation.id).to eq existing.id
+            expect(status.conversation.inbox_url).to eq 'http://example.com/actor/inbox'
+          end
+        end
+      end
+
+      context 'with an invalid context' do
+        let(:object_json) do
+          {
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+            type: 'Note',
+            content: 'Lorem ipsum',
+            context: 'http://example.com/invalid-conversation',
+          }
+        end
+
+        it 'creates status' do
+          status = sender.statuses.first
+
+          expect(status).to_not be_nil
+          expect(status.text).to eq 'Lorem ipsum'
+          expect(status.conversation).to_not be_nil
+          expect(status.conversation.uri).to eq 'http://example.com/invalid-conversation'
+        end
+      end
+
+      context 'with a local context' do
+        let(:object_json) do
+          {
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+            type: 'Note',
+            content: 'Lorem ipsum',
+            context: "https://cb6e6126.ngrok.io/contexts/#{existing.id}",
+          }
+        end
+
+        let(:existing) { Fabricate(:conversation, id: 3500) }
+
+        it 'creates status' do
+          status = sender.statuses.first
+
+          expect(status).to_not be_nil
+          expect(status.conversation).to_not be_nil
+          expect(status.conversation.uri).to be_nil
+          expect(status.conversation.id).to eq existing.id
+        end
+      end
+
+      context 'with a context as a reply' do
+        let(:custom_before) { true }
+        let(:custom_before_sub) { false }
+        let(:ancestor_account) { Fabricate(:account, domain: 'or.example.com', inbox_url: 'http://or.example.com/actor/inbox') }
+        let(:mentioned_account) { Fabricate(:account, domain: 'example.com', uri: 'http://example.com/bob', inbox_url: 'http://example.com/bob/inbox', shared_inbox_url: 'http://exmaple.com/inbox') }
+        let(:local_mentioned_account) { Fabricate(:account, domain: nil) }
+        let(:original_status) { Fabricate(:status, conversation: conversation, account: ancestor_account) }
+        let!(:conversation) { Fabricate(:conversation) }
+        let(:recipient) { Fabricate(:account) }
+        let(:delivered_to_account_id) { recipient.id }
+
+        let(:json) do
+          {
+            '@context': 'https://www.w3.org/ns/activitystreams',
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#foo'].join,
+            type: 'Create',
+            actor: ActivityPub::TagManager.instance.uri_for(sender),
+            object: object_json,
+            signature: 'dummy',
+          }.with_indifferent_access
+        end
+
+        let(:object_json) do
+          {
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+            type: 'Note',
+            content: 'Lorem ipsum',
+            context: ActivityPub::TagManager.instance.uri_for(conversation),
+            inReplyTo: ActivityPub::TagManager.instance.uri_for(original_status),
+          }
+        end
+
+        before do
+          original_status.mentions << Fabricate(:mention, account: mentioned_account, silent: true)
+          original_status.mentions << Fabricate(:mention, account: local_mentioned_account, silent: true)
+          original_status.save!
+          conversation.update(ancestor_status: original_status)
+
+          stub_request(:post, 'http://or.example.com/actor/inbox').to_return(status: 200)
+          stub_request(:post, 'http://example.com/bob/inbox').to_return(status: 200)
+
+          subject.perform unless custom_before_sub
+        end
+
+        it 'creates status' do
+          status = sender.statuses.first
+
+          expect(status).to_not be_nil
+          expect(status.conversation_id).to eq conversation.id
+          expect(status.thread.id).to eq original_status.id
+          expect(status.mentions.map(&:account_id)).to contain_exactly(recipient.id, ancestor_account.id, mentioned_account.id, local_mentioned_account.id)
+        end
+
+        it 'forwards to observers' do
+          expect(a_request(:post, 'http://or.example.com/actor/inbox')).to have_been_made.once
+          expect(a_request(:post, 'http://example.com/bob/inbox')).to have_been_made.once
+        end
+
+        context 'when new mention is added' do
+          let(:custom_before_sub) { true }
+
+          let(:new_mentioned_account) { Fabricate(:account, domain: 'example.com', uri: 'http://example.com/alice', inbox_url: 'http://example.com/alice/inbox', shared_inbox_url: 'http://exmaple.com/inbox') }
+          let(:new_local_mentioned_account) { Fabricate(:account, domain: nil) }
+
+          let(:object_json) do
+            {
+              id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+              type: 'Note',
+              content: 'Lorem ipsum',
+              context: ActivityPub::TagManager.instance.uri_for(conversation),
+              inReplyTo: ActivityPub::TagManager.instance.uri_for(original_status),
+              tag: [
+                {
+                  type: 'Mention',
+                  href: ActivityPub::TagManager.instance.uri_for(new_mentioned_account),
+                },
+                {
+                  type: 'Mention',
+                  href: ActivityPub::TagManager.instance.uri_for(new_local_mentioned_account),
+                },
+              ],
+            }
+          end
+
+          before do
+            stub_request(:post, 'http://example.com/alice/inbox').to_return(status: 200)
+            subject.perform
+          end
+
+          it 'creates status' do
+            status = sender.statuses.first
+
+            expect(status).to_not be_nil
+            expect(status.mentions.map(&:account_id)).to contain_exactly(recipient.id, ancestor_account.id, mentioned_account.id, local_mentioned_account.id, new_mentioned_account.id, new_local_mentioned_account.id)
+          end
+
+          it 'forwards to observers' do
+            expect(a_request(:post, 'http://or.example.com/actor/inbox')).to have_been_made.once
+            expect(a_request(:post, 'http://example.com/bob/inbox')).to have_been_made.once
+            expect(a_request(:post, 'http://example.com/alice/inbox')).to have_been_made.once
+          end
+        end
+
+        context 'when unknown mentioned account' do
+          let(:custom_before_sub) { true }
+
+          let(:actor_json) do
+            {
+              '@context': 'https://www.w3.org/ns/activitystreams',
+              id: 'https://foo.test',
+              type: 'Person',
+              preferredUsername: 'actor',
+              name: 'Tomas Cat',
+              inbox: 'https://foo.test/inbox',
+            }.with_indifferent_access
+          end
+          let!(:webfinger) { { subject: 'acct:actor@foo.test', links: [{ rel: 'self', href: 'https://foo.test' }] } }
+
+          let(:object_json) do
+            {
+              id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+              type: 'Note',
+              content: 'Lorem ipsum',
+              context: ActivityPub::TagManager.instance.uri_for(conversation),
+              inReplyTo: ActivityPub::TagManager.instance.uri_for(original_status),
+              tag: [
+                {
+                  type: 'Mention',
+                  href: 'https://foo.test',
+                },
+              ],
+            }
+          end
+
+          before do
+            stub_request(:get, 'https://foo.test').to_return(status: 200, body: Oj.dump(actor_json))
+            stub_request(:get, 'https://foo.test/.well-known/webfinger?resource=acct:actor@foo.test').to_return(status: 200, body: Oj.dump(webfinger))
+            stub_request(:post, 'https://foo.test/inbox').to_return(status: 200)
+            stub_request(:get, 'https://foo.test/.well-known/nodeinfo').to_return(status: 200)
+            subject.perform
+          end
+
+          it 'creates status' do
+            status = sender.statuses.first
+
+            expect(status).to_not be_nil
+            expect(status.mentioned_accounts.map(&:uri)).to include 'https://foo.test'
+          end
+
+          it 'forwards to observers' do
+            expect(a_request(:post, 'https://foo.test/inbox')).to have_been_made.once
+          end
+        end
+
+        context 'when remote conversation' do
+          let(:conversation) { Fabricate(:conversation, uri: 'http://example.com/conversation', inbox_url: 'http://example.com/actor/inbox') }
+
+          it 'creates status' do
+            status = sender.statuses.first
+
+            expect(status).to_not be_nil
+            expect(status.conversation_id).to eq conversation.id
+            expect(status.thread.id).to eq original_status.id
+            expect(status.mentions.map(&:account_id)).to contain_exactly(recipient.id)
+          end
+
+          it 'do not forward to observers' do
+            expect(a_request(:post, 'http://or.example.com/actor/inbox')).to_not have_been_made
+            expect(a_request(:post, 'http://example.com/bob/inbox')).to_not have_been_made
+          end
+        end
+      end
+
       context 'with media attachments' do
         let(:object_json) do
           {
diff --git a/spec/lib/activitypub/activity/delete_spec.rb b/spec/lib/activitypub/activity/delete_spec.rb
index f0c957c8a1..5fd0c557ff 100644
--- a/spec/lib/activitypub/activity/delete_spec.rb
+++ b/spec/lib/activitypub/activity/delete_spec.rb
@@ -74,6 +74,27 @@ RSpec.describe ActivityPub::Activity::Delete do
     end
   end
 
+  context 'when the status is limited post and has conversation' do
+    subject { described_class.new(json, sender) }
+
+    let(:conversation) { Fabricate(:conversation, ancestor_status: status) }
+
+    before do
+      status.update(conversation: conversation, visibility: :limited)
+      status.mentions << Fabricate(:mention, silent: true, account: Fabricate(:account, protocol: :activitypub, domain: 'example.com', inbox_url: 'https://example.com/actor/inbox', shared_inbox_url: 'https://example.com/inbox'))
+      status.save
+      stub_request(:post, 'https://example.com/inbox').to_return(status: 200)
+      subject.perform
+    end
+
+    it 'forwards to parent status holder' do
+      expect(a_request(:post, 'https://example.com/inbox').with(body: hash_including({
+        type: 'Delete',
+        signature: 'foo',
+      }))).to have_been_made.once
+    end
+  end
+
   context 'when given a friend server' do
     subject { described_class.new(json, sender) }
 
diff --git a/spec/lib/activitypub/activity/update_spec.rb b/spec/lib/activitypub/activity/update_spec.rb
index 87e96d2d1b..c300768ff2 100644
--- a/spec/lib/activitypub/activity/update_spec.rb
+++ b/spec/lib/activitypub/activity/update_spec.rb
@@ -115,5 +115,39 @@ RSpec.describe ActivityPub::Activity::Update do
         expect(status.edited_at).to be_nil
       end
     end
+
+    context 'when the status is limited post and has conversation' do
+      let(:status) { Fabricate(:status, visibility: :limited, account: sender, uri: 'https://example.com/note', text: 'Ohagi is koshian') }
+      let(:conversation) { Fabricate(:conversation, ancestor_status: status) }
+      let(:json) do
+        {
+          '@context': 'https://www.w3.org/ns/activitystreams',
+          id: 'foo',
+          type: 'Update',
+          actor: sender.uri,
+          signature: 'foo',
+          object: {
+            type: 'Note',
+            id: status.uri,
+            content: 'Ohagi is tsubuan',
+          },
+        }.with_indifferent_access
+      end
+
+      before do
+        status.update(conversation: conversation, visibility: :limited)
+        status.mentions << Fabricate(:mention, silent: true, account: Fabricate(:account, protocol: :activitypub, domain: 'example.com', inbox_url: 'https://example.com/actor/inbox', shared_inbox_url: 'https://example.com/inbox'))
+        status.save
+        stub_request(:post, 'https://example.com/inbox').to_return(status: 200)
+        subject.perform
+      end
+
+      it 'forwards to parent status holder' do
+        expect(a_request(:post, 'https://example.com/inbox').with(body: hash_including({
+          type: 'Update',
+          signature: 'foo',
+        }))).to have_been_made.once
+      end
+    end
   end
 end
diff --git a/spec/models/status_spec.rb b/spec/models/status_spec.rb
index 4e10f3d316..5036777c82 100644
--- a/spec/models/status_spec.rb
+++ b/spec/models/status_spec.rb
@@ -593,6 +593,16 @@ RSpec.describe Status do
       expect(described_class.create(account: alice, text: 'First').conversation_id).to_not be_nil
     end
 
+    it 'creates new owned-conversation for stand-alone status' do
+      expect(described_class.create(account: alice, text: 'First').owned_conversation.id).to_not be_nil
+    end
+
+    it 'creates new owned-conversation and linked for stand-alone status' do
+      status = described_class.create(account: alice, text: 'First')
+      expect(status.owned_conversation.ancestor_status_id).to eq status.id
+      expect(status.conversation.ancestor_status_id).to eq status.id
+    end
+
     it 'keeps conversation of parent node' do
       parent = Fabricate(:status, text: 'First')
       expect(described_class.create(account: alice, thread: parent, text: 'Response').conversation_id).to eq parent.conversation_id
diff --git a/spec/policies/status_policy_spec.rb b/spec/policies/status_policy_spec.rb
index 3bdc2084d8..6bfc02c582 100644
--- a/spec/policies/status_policy_spec.rb
+++ b/spec/policies/status_policy_spec.rb
@@ -115,6 +115,58 @@ RSpec.describe StatusPolicy, type: :model do
     end
   end
 
+  context 'with the permission of show_mentioned_users?' do
+    permissions :show_mentioned_users? do
+      it 'grants access when public and account is viewer' do
+        status.visibility = :public
+
+        expect(subject).to permit(status.account, status)
+      end
+
+      it 'grants access when public and account is not viewer' do
+        status.visibility = :public
+
+        expect(subject).to_not permit(bob, status)
+      end
+
+      it 'grants access when limited and no conversation ancestor_status and account is viewer' do
+        status.visibility = :limited
+        status.conversation = Fabricate(:conversation)
+
+        expect(subject).to permit(status.account, status)
+      end
+
+      it 'grants access when limited and my conversation and account is viewer' do
+        status.visibility = :limited
+        status.conversation = Fabricate(:conversation, ancestor_status: status)
+
+        expect(subject).to permit(status.account, status)
+      end
+
+      it 'grants access when limited and another conversation and account is viewer' do
+        status.visibility = :limited
+        status.conversation = Fabricate(:conversation, ancestor_status: Fabricate(:status, account: bob))
+
+        expect(subject).to_not permit(status.account, status)
+      end
+
+      it 'grants access when limited and viewer is mentioned' do
+        status.visibility = :limited
+        status.mentions = [Fabricate(:mention, account: bob)]
+
+        expect(subject).to_not permit(bob, status)
+      end
+
+      it 'grants access when limited and non-owner viewer is mentioned and mentions are loaded' do
+        status.visibility = :limited
+        status.mentions = [Fabricate(:mention, account: bob)]
+        status.mentions.load
+
+        expect(subject).to_not permit(bob, status)
+      end
+    end
+  end
+
   context 'with the permission of reblog?' do
     permissions :reblog? do
       it 'denies access when private' do
diff --git a/spec/services/fan_out_on_write_service_spec.rb b/spec/services/fan_out_on_write_service_spec.rb
index d7393a7e5e..aa6c64624e 100644
--- a/spec/services/fan_out_on_write_service_spec.rb
+++ b/spec/services/fan_out_on_write_service_spec.rb
@@ -683,6 +683,84 @@ RSpec.describe FanOutOnWriteService, type: :service do
     end
   end
 
+  context 'when status has a conversation' do
+    let(:conversation) { Fabricate(:conversation) }
+    let(:status) { Fabricate(:status, account: alice, visibility: visibility, thread: parent_status, conversation: conversation) }
+    let(:parent_status) { Fabricate(:status, account: bob, visibility: visibility, conversation: conversation) }
+    let(:zilu) { Fabricate(:user, current_sign_in_at: last_active_at).account }
+    let(:custom_before) { true }
+
+    before do
+      zilu.follow!(alice)
+      zilu.follow!(bob)
+      Fabricate(:status, account: tom, visibility: visibility, conversation: conversation)
+      Fabricate(:status, account: ohagi, visibility: visibility, conversation: conversation)
+      status.mentions << Fabricate(:mention, account: bob, silent: true)
+      status.mentions << Fabricate(:mention, account: ohagi, silent: true)
+      status.mentions << Fabricate(:mention, account: zilu, silent: true)
+      status.mentions << Fabricate(:mention, account: tom, silent: false)
+      status.save
+      subject.call(status)
+    end
+
+    context 'when public visibility' do
+      it 'does not create notification' do
+        notification = Notification.find_by(account: bob, type: 'mention')
+
+        expect(notification).to be_nil
+      end
+
+      it 'creates notification for active mention' do
+        notification = Notification.find_by(account: tom, type: 'mention')
+
+        expect(notification).to_not be_nil
+        expect(notification.mention.status_id).to eq status.id
+      end
+
+      it 'inserts home feed for reply' do
+        expect(home_feed_of(bob)).to include status.id
+      end
+
+      it 'inserts home feed for non-replied but mentioned and following replied account' do
+        expect(home_feed_of(zilu)).to include status.id
+      end
+
+      it 'does not insert home feed for non-replied, non-following replied account but mentioned' do
+        expect(home_feed_of(tom)).to_not include status.id
+      end
+    end
+
+    context 'when limited visibility' do
+      let(:visibility) { :limited }
+
+      it 'creates notification' do
+        notification = Notification.find_by(account: bob, type: 'mention')
+
+        expect(notification).to_not be_nil
+        expect(notification.mention.status_id).to eq status.id
+      end
+
+      it 'creates notification for other conversation account' do
+        notification = Notification.find_by(account: ohagi, type: 'mention')
+
+        expect(notification).to_not be_nil
+        expect(notification.mention.status_id).to eq status.id
+      end
+
+      it 'inserts home feed for reply' do
+        expect(home_feed_of(bob)).to include status.id
+      end
+
+      it 'inserts home feed for non-replied but mentioned and following replied account' do
+        expect(home_feed_of(zilu)).to include status.id
+      end
+
+      it 'does not insert home feed for non-replied, non-following replied account but mentioned' do
+        expect(home_feed_of(tom)).to_not include status.id
+      end
+    end
+  end
+
   context 'when updated status is already boosted or quoted' do
     let(:custom_before) { true }
 
diff --git a/spec/services/post_status_service_spec.rb b/spec/services/post_status_service_spec.rb
index e27baf13a9..455dac4e7e 100644
--- a/spec/services/post_status_service_spec.rb
+++ b/spec/services/post_status_service_spec.rb
@@ -263,7 +263,7 @@ RSpec.describe PostStatusService, type: :service do
     expect(status.limited_scope).to eq 'circle'
   end
 
-  it 'limited visibility and empty circle' do
+  it 'limited visibility without circle' do
     account = Fabricate(:account)
     text = 'This is an English text.'
 
@@ -295,6 +295,158 @@ RSpec.describe PostStatusService, type: :service do
     expect(status.mentioned_accounts.count).to eq 1
   end
 
+  describe 'create a new response status to limited post' do
+    it 'when reply visibility' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      account = Fabricate(:account)
+      text = 'test status update'
+
+      status = subject.call(account, text: text, thread: in_reply_to_status, visibility: 'reply')
+
+      expect(status).to be_persisted
+      expect(status.thread).to eq in_reply_to_status
+      expect(status.visibility).to eq 'limited'
+      expect(status.limited_scope).to eq 'reply'
+    end
+
+    it 'when limited visibility' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      account = Fabricate(:account)
+      text = 'test status update'
+
+      status = subject.call(account, text: text, thread: in_reply_to_status, visibility: 'limited')
+
+      expect(status).to be_persisted
+      expect(status.thread).to eq in_reply_to_status
+      expect(status.visibility).to eq 'limited'
+      expect(status.limited_scope).to eq 'reply'
+    end
+
+    it 'when circle visibility' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      account = Fabricate(:account)
+      text = 'test status update'
+
+      circle = Fabricate(:circle, account: account)
+      circle_account = Fabricate(:account)
+      circle_account.follow!(account)
+      circle.accounts << circle_account
+      circle.save!
+
+      status = subject.call(account, text: text, thread: in_reply_to_status, visibility: 'circle', circle_id: circle.id)
+
+      expect(status).to be_persisted
+      expect(status.thread).to eq in_reply_to_status
+      expect(status.visibility).to eq 'limited'
+      expect(status.limited_scope).to eq 'circle'
+      expect(status.mentioned_accounts.pluck(:id)).to eq [circle_account.id]
+    end
+
+    it 'when public visibility' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      account = Fabricate(:account)
+      text = 'test status update'
+
+      status = subject.call(account, text: text, thread: in_reply_to_status, visibility: :public)
+
+      expect(status).to be_persisted
+      expect(status.thread).to eq in_reply_to_status
+      expect(status.visibility).to eq 'public'
+    end
+
+    it 'when direct visibility' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      account = Fabricate(:account)
+      text = 'test status update'
+
+      status = subject.call(account, text: text, thread: in_reply_to_status, visibility: :direct)
+
+      expect(status).to be_persisted
+      expect(status.thread).to eq in_reply_to_status
+      expect(status.visibility).to eq 'direct'
+    end
+
+    it 'duplicate replies' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      in_reply_to_status.mentions.create!(account: Fabricate(:account))
+
+      status = subject.call(Fabricate(:user).account, text: 'Ohagi is good', thread: in_reply_to_status, visibility: 'reply')
+
+      thread_account_ids = [in_reply_to_status.account, in_reply_to_status.mentions.first.account].map(&:id)
+
+      expect(status).to be_persisted
+      expect(status.conversation_id).to eq in_reply_to_status.conversation_id
+      expect(status.conversation.ancestor_status_id).to eq in_reply_to_status.id
+      expect(status.mentions.pluck(:account_id)).to match_array thread_account_ids
+    end
+
+    it 'duplicate reply-to-reply' do
+      ancestor_account = Fabricate(:account, username: 'ancestor', domain: nil)
+      reply_account = Fabricate(:account)
+
+      first_status = Fabricate(:status, account: ancestor_account, visibility: :limited)
+      in_reply_to_status = subject.call(reply_account, text: 'Ohagi is good, @ancestor', thread: first_status, visibility: 'reply')
+      status = subject.call(ancestor_account, text: 'Ohagi is good', thread: in_reply_to_status, visibility: 'reply')
+
+      thread_account_ids = [ancestor_account, reply_account].map(&:id)
+
+      expect(status).to be_persisted
+      expect(status.conversation_id).to eq in_reply_to_status.conversation_id
+      expect(status.conversation_id).to eq first_status.conversation_id
+      expect(status.conversation.ancestor_status_id).to eq first_status.id
+      expect(status.mentions.pluck(:account_id)).to match_array thread_account_ids
+    end
+
+    it 'duplicate reply-to-third_reply' do
+      first_status = Fabricate(:status, visibility: :limited)
+      first_status.mentions.create!(account: Fabricate(:account))
+
+      mentioned_account = Fabricate(:account, username: 'ohagi', domain: nil)
+      mentioned_account2 = Fabricate(:account, username: 'bob', domain: nil)
+      in_reply_to_status = subject.call(Fabricate(:user).account, text: 'Ohagi is good, @ohagi', thread: first_status, visibility: 'reply')
+      status = subject.call(Fabricate(:user).account, text: 'Ohagi is good, @bob', thread: in_reply_to_status, visibility: 'reply')
+
+      thread_account_ids = [first_status.account, first_status.mentions.first.account, mentioned_account, mentioned_account2, in_reply_to_status.account].map(&:id)
+
+      expect(status).to be_persisted
+      expect(status.conversation_id).to eq in_reply_to_status.conversation_id
+      expect(status.conversation_id).to eq first_status.conversation_id
+      expect(status.conversation.ancestor_status_id).to eq first_status.id
+      expect(status.mentions.pluck(:account_id)).to match_array thread_account_ids
+    end
+
+    it 'do not duplicate replies when limited post' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      in_reply_to_status.mentions.create!(account: Fabricate(:account))
+
+      status = subject.call(Fabricate(:user).account, text: 'Ohagi is good', thread: in_reply_to_status, visibility: 'mutual')
+
+      [in_reply_to_status.account, in_reply_to_status.mentions.first.account].map(&:id)
+
+      expect(status).to be_persisted
+      expect(status.limited_scope).to eq 'personal'
+
+      mentions = status.mentions.pluck(:account_id)
+      expect(mentions).to_not include in_reply_to_status.account_id
+      expect(mentions).to_not include in_reply_to_status.mentions.first.account_id
+    end
+
+    it 'do not duplicate replies when not limited post' do
+      in_reply_to_status = Fabricate(:status, visibility: :limited)
+      in_reply_to_status.mentions.create!(account: Fabricate(:account))
+
+      status = subject.call(Fabricate(:user).account, text: 'Ohagi is good', thread: in_reply_to_status, visibility: 'public')
+
+      [in_reply_to_status.account, in_reply_to_status.mentions.first.account].map(&:id)
+
+      expect(status).to be_persisted
+
+      mentions = status.mentions.pluck(:account_id)
+      expect(mentions).to_not include in_reply_to_status.account_id
+      expect(mentions).to_not include in_reply_to_status.mentions.first.account_id
+    end
+  end
+
   it 'safeguards mentions' do
     account = Fabricate(:account)
     mentioned_account = Fabricate(:account, username: 'alice')
diff --git a/spec/services/remove_status_service_spec.rb b/spec/services/remove_status_service_spec.rb
index 7754ae8004..bbba222f75 100644
--- a/spec/services/remove_status_service_spec.rb
+++ b/spec/services/remove_status_service_spec.rb
@@ -8,12 +8,14 @@ RSpec.describe RemoveStatusService, type: :service do
   let!(:alice)  { Fabricate(:account) }
   let!(:bob)    { Fabricate(:account, username: 'bob', domain: 'example.com') }
   let!(:jeff)   { Fabricate(:account) }
-  let!(:hank)   { Fabricate(:account, username: 'hank', protocol: :activitypub, domain: 'example.com', inbox_url: 'http://example.com/inbox') }
-  let!(:bill)   { Fabricate(:account, username: 'bill', protocol: :activitypub, domain: 'example2.com', inbox_url: 'http://example2.com/inbox') }
+  let!(:hank)   { Fabricate(:account, username: 'hank', protocol: :activitypub, domain: 'example.com', shared_inbox_url: 'http://example.com/inbox', inbox_url: 'http://example.com/hank/inbox') }
+  let!(:bill)   { Fabricate(:account, username: 'bill', protocol: :activitypub, domain: 'example2.com', shared_inbox_url: 'http://example2.com/inbox', inbox_url: 'http://example2.com/bill/inbox') }
 
   before do
     stub_request(:post, 'http://example.com/inbox').to_return(status: 200)
+    stub_request(:post, 'http://example.com/hank/inbox').to_return(status: 200)
     stub_request(:post, 'http://example2.com/inbox').to_return(status: 200)
+    stub_request(:post, 'http://example2.com/bill/inbox').to_return(status: 200)
 
     jeff.follow!(alice)
     hank.follow!(alice)
@@ -72,6 +74,57 @@ RSpec.describe RemoveStatusService, type: :service do
     end
   end
 
+  context 'when removed status is limited' do
+    let(:status) { PostStatusService.new.call(alice, visibility: 'mutual', text: 'limited post') }
+
+    before do
+      status.mentions << Fabricate(:mention, account: hank, silent: true)
+    end
+
+    it 'sends Delete activity to followers' do
+      subject.call(status)
+      expect(a_request(:post, 'http://example.com/inbox').with(
+               body: hash_including({
+                 'type' => 'Delete',
+                 'object' => {
+                   'type' => 'Tombstone',
+                   'id' => ActivityPub::TagManager.instance.uri_for(status),
+                   'atomUri' => OStatus::TagManager.instance.uri_for(status),
+                 },
+               })
+             )).to have_been_made.once
+    end
+  end
+
+  context 'when removed status is limited and remote conversation' do
+    let(:status) { PostStatusService.new.call(alice, visibility: 'mutual', text: 'limited post') }
+
+    before do
+      status.conversation.update(uri: 'http://example2.com/conversation', inbox_url: 'http://example2.com/bill/inbox')
+      status.mentions << Fabricate(:mention, account: hank, silent: true)
+    end
+
+    it 'sends Delete activity to conversation' do
+      subject.call(status)
+      expect(a_request(:post, 'http://example2.com/bill/inbox').with(
+               body: hash_including({
+                 'type' => 'Delete',
+                 'object' => {
+                   'type' => 'Tombstone',
+                   'id' => ActivityPub::TagManager.instance.uri_for(status),
+                   'atomUri' => OStatus::TagManager.instance.uri_for(status),
+                 },
+               })
+             )).to have_been_made.once
+    end
+
+    it 'do not send Delete activity to followers' do
+      subject.call(status)
+      expect(a_request(:post, 'http://example.com/hank/inbox')).to_not have_been_made
+      expect(a_request(:post, 'http://example.com/inbox')).to_not have_been_made
+    end
+  end
+
   context 'when removed status is a private self-reblog' do
     let!(:original_status) { Fabricate(:status, account: alice, text: 'Hello ThisIsASecret', visibility: :private) }
     let!(:status) { ReblogService.new.call(alice, original_status) }
diff --git a/spec/workers/activitypub/distribution_worker_spec.rb b/spec/workers/activitypub/distribution_worker_spec.rb
index 3a820b2bbf..523cab85bf 100644
--- a/spec/workers/activitypub/distribution_worker_spec.rb
+++ b/spec/workers/activitypub/distribution_worker_spec.rb
@@ -63,6 +63,22 @@ describe ActivityPub::DistributionWorker do
       end
     end
 
+    context 'with limited response status' do
+      before do
+        allow(ActivityPub::DeliveryWorker).to receive(:perform_async).with(kind_of(String), status.account.id, 'http://example.com/conversation/inbox', anything)
+        status.update(visibility: :limited, thread: Fabricate(:status))
+        status.conversation.update(uri: 'https://example.com/conversation', inbox_url: 'http://example.com/conversation/inbox')
+        status.capability_tokens.create!
+        status.mentions.create!(account: follower, silent: true)
+        stub_request(:post, 'http://example.com/conversation/inbox')
+      end
+
+      it 'delivers to followers' do
+        subject.perform(status.id)
+        expect(ActivityPub::DeliveryWorker).to have_received(:perform_async)
+      end
+    end
+
     context 'with limited status for no-follower but non-mentioned follower' do
       let(:no_follower) { Fabricate(:account, domain: 'example.com', inbox_url: 'http://example.com/no_follower/inbox', shared_inbox_url: 'http://example.com') }
 
diff --git a/spec/workers/activitypub/status_update_distribution_worker_spec.rb b/spec/workers/activitypub/status_update_distribution_worker_spec.rb
index a4fd246e53..8f2cefcc32 100644
--- a/spec/workers/activitypub/status_update_distribution_worker_spec.rb
+++ b/spec/workers/activitypub/status_update_distribution_worker_spec.rb
@@ -6,7 +6,7 @@ describe ActivityPub::StatusUpdateDistributionWorker do
   subject { described_class.new }
 
   let(:status)   { Fabricate(:status, text: 'foo') }
-  let(:follower) { Fabricate(:account, protocol: :activitypub, inbox_url: 'http://example.com', domain: 'example.com') }
+  let(:follower) { Fabricate(:account, protocol: :activitypub, shared_inbox_url: 'http://example.com', inbox_url: 'http://example.com/follower/inbox', domain: 'example.com') }
 
   describe '#perform' do
     before do
@@ -31,6 +31,18 @@ describe ActivityPub::StatusUpdateDistributionWorker do
       end
     end
 
+    context 'with unlisted status' do
+      before do
+        status.update(visibility: :unlisted)
+      end
+
+      it 'delivers to followers' do
+        expect_push_bulk_to_match(ActivityPub::DeliveryWorker, [[kind_of(String), status.account.id, 'http://example.com', anything]]) do
+          subject.perform(status.id)
+        end
+      end
+    end
+
     context 'with private status' do
       before do
         status.update(visibility: :private)
@@ -42,5 +54,35 @@ describe ActivityPub::StatusUpdateDistributionWorker do
         end
       end
     end
+
+    context 'with limited status' do
+      before do
+        status.update(visibility: :limited)
+        status.capability_tokens.create!
+        status.mentions.create!(account: follower, silent: true)
+      end
+
+      it 'delivers to followers' do
+        expect_push_bulk_to_match(ActivityPub::DeliveryWorker, [[kind_of(String), status.account.id, 'http://example.com', anything]]) do
+          subject.perform(status.id)
+        end
+      end
+    end
+
+    context 'with limited response status' do
+      before do
+        allow(ActivityPub::DeliveryWorker).to receive(:perform_async).with(kind_of(String), status.account.id, 'http://example.com/conversation/inbox', anything)
+        status.update(visibility: :limited, thread: Fabricate(:status))
+        status.conversation.update(uri: 'https://example.com/conversation', inbox_url: 'http://example.com/conversation/inbox')
+        status.capability_tokens.create!
+        status.mentions.create!(account: follower, silent: true)
+        stub_request(:post, 'http://example.com/conversation/inbox')
+      end
+
+      it 'delivers to followers' do
+        subject.perform(status.id)
+        expect(ActivityPub::DeliveryWorker).to have_received(:perform_async)
+      end
+    end
   end
 end