add ability for post authors to kick jerks out of their threads

app/lib/activitypub/activity/create.rb

@@ -66,7 +66,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     @mentions_local_account = false
 
     process_status_params
-    return reject_payload! if twitter_retweet? || recipient_rejects_replies?
+    return reject_payload! if twitter_retweet? || recipient_rejects_replies? || kicked?
 
     process_tags
     process_audience
@@ -109,6 +109,11 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
       @params[:thread]&.account_id != @account.id
   end
 
+  def kicked?
+    @params[:conversation].present? &&
+      @params[:conversation].kicks.where(account_id: @account.id).exists?
+  end
+
   def process_status_params
     @params = begin
       {

app/models/concerns/account_associations.rb

@@ -61,5 +61,8 @@ module AccountAssociations
 
     # queued boosts
     has_many :queued_boosts, dependent: :destroy, inverse_of: :account
+
+    # kicked-out-of conversations
+    has_many :conversation_kicks, dependent: :destroy, inverse_of: :account
   end
 end

app/models/concerns/status_threading_concern.rb

@@ -127,7 +127,8 @@ module StatusThreadingConcern
   end
 
   def statuses_with_accounts(ids)
-    Status.where(id: ids).includes(:account)
+    kicked_accounts = ConversationKick.select(:account_id).where(conversation_id: self.conversation_id)
+    Status.where(id: ids).where.not(account_id: kicked_accounts).includes(:account)
   end
 
   def filter_from_context?(status, account, relations)

app/models/conversation.rb

@@ -13,6 +13,7 @@ class Conversation < ApplicationRecord
   validates :uri, uniqueness: true, if: :uri?
 
   has_many :statuses
+  has_many :kicks, class_name: 'ConversationKick', inverse_of: :conversation, dependent: :destroy
 
   def local?
     uri.nil?

app/models/conversation_kick.rb

@@ -0,0 +1,13 @@
+# == Schema Information
+#
+# Table name: conversation_kicks
+#
+#  id              :bigint(8)        not null, primary key
+#  account_id      :bigint(8)        not null
+#  conversation_id :bigint(8)        not null
+#
+
+class ConversationKick < ApplicationRecord
+  belongs_to :account
+  belongs_to :conversation
+end

app/services/remove_status_for_account_service.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class RemoveStatusForAccountService < BaseService
+  include Redisable
+
+  def call(account, status)
+    @account      = account
+    @status       = status
+    @payload      = Oj.dump(event: :delete, payload: status.id.to_s)
+
+    RedisLock.acquire(lock_options) do |lock|
+      if lock.acquired?
+        remove_from_feeds
+        remove_from_lists
+      else
+        raise Mastodon::RaceConditionError
+      end
+    end
+  end
+
+  private
+
+  def remove_from_feeds
+    FeedManager.instance.unpush_from_home(@account, @status)
+    Redis.current.publish("timeline:direct:#{@account.id}", @payload)
+    redis.publish("timeline:#{@account.id}", @payload)
+  end
+
+  def remove_from_lists
+    @account.lists_for_local_distribution.select(:id, :account_id).reorder(nil).find_each do |list|
+      FeedManager.instance.unpush_from_list(list, @status)
+    end
+  end
+
+  def lock_options
+    { redis: Redis.current, key: "distribute:#{@status.id}" }
+  end
+end

config/locales/en.yml

@@ -975,6 +975,7 @@ en:
         other: "%{count} votes"
       vote: Vote
     replies_rejected: 'The author is not accepting replies to this roar.'
+    kicked: "You do not have the author's permission to reply to this thread."
     show_more: Show more
     sign_in_to_participate: Sign in to participate in the conversation
     title: '%{name}: "%{quote}"'

db/migrate/20191212043419_create_conversation_kicks.rb

@@ -0,0 +1,10 @@
+class CreateConversationKicks < ActiveRecord::Migration[5.2]
+  def change
+    create_table :conversation_kicks do |t|
+      t.references :account, null: false, foreign_key: {on_delete: :cascade}
+      t.references :conversation, null: false, foreign_key: {on_delete: :cascade}
+    end
+
+    add_index :conversation_kicks, [:account_id, :conversation_id], unique: true
+  end
+end

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: 2019_12_12_022653) do
+ActiveRecord::Schema.define(version: 2019_12_12_043419) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -218,6 +218,14 @@ ActiveRecord::Schema.define(version: 2019_12_12_022653) do
     t.index ["status_id"], name: "index_bookmarks_on_status_id"
   end
 
+  create_table "conversation_kicks", force: :cascade do |t|
+    t.bigint "account_id", null: false
+    t.bigint "conversation_id", null: false
+    t.index ["account_id", "conversation_id"], name: "index_conversation_kicks_on_account_id_and_conversation_id", unique: true
+    t.index ["account_id"], name: "index_conversation_kicks_on_account_id"
+    t.index ["conversation_id"], name: "index_conversation_kicks_on_conversation_id"
+  end
+
   create_table "conversation_mutes", force: :cascade do |t|
     t.bigint "conversation_id", null: false
     t.bigint "account_id", null: false
@@ -846,6 +854,8 @@ ActiveRecord::Schema.define(version: 2019_12_12_022653) do
   add_foreign_key "blocks", "accounts", name: "fk_4269e03e65", on_delete: :cascade
   add_foreign_key "bookmarks", "accounts", on_delete: :cascade
   add_foreign_key "bookmarks", "statuses", on_delete: :cascade
+  add_foreign_key "conversation_kicks", "accounts", on_delete: :cascade
+  add_foreign_key "conversation_kicks", "conversations", on_delete: :cascade
   add_foreign_key "conversation_mutes", "accounts", name: "fk_225b4212bb", on_delete: :cascade
   add_foreign_key "conversation_mutes", "conversations", on_delete: :cascade
   add_foreign_key "custom_filters", "accounts", on_delete: :cascade

spec/fabricators/conversation_kick_fabricator.rb

@@ -0,0 +1,4 @@
+Fabricator(:conversation_kick) do
+  account      nil
+  conversation nil
+end

spec/models/conversation_kick_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe ConversationKick, type: :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end