Change link previews to keep original URL from the status (#27312)

app/models/admin/status_batch_action.rb

@@ -74,7 +74,7 @@ class Admin::StatusBatchAction
 
     # Can't use a transaction here because UpdateStatusService queues
     # Sidekiq jobs
-    statuses.includes(:media_attachments, :preview_cards).find_each do |status|
+    statuses.includes(:media_attachments, preview_cards_status: :preview_card).find_each do |status|
       next if status.discarded? || !(status.with_media? || status.with_preview_card?)
 
       authorize([:admin, status], :update?)

app/models/concerns/status_search_concern.rb

@@ -40,7 +40,7 @@ module StatusSearchConcern
       properties << 'media' if with_media?
       properties << 'poll' if with_poll?
       properties << 'link' if with_preview_card?
-      properties << 'embed' if preview_cards.any?(&:video?)
+      properties << 'embed' if preview_card&.video?
       properties << 'sensitive' if sensitive?
       properties << 'reply' if reply?
     end

app/models/preview_card.rb

@@ -50,7 +50,9 @@ class PreviewCard < ApplicationRecord
   enum type: { link: 0, photo: 1, video: 2, rich: 3 }
   enum link_type: { unknown: 0, article: 1 }
 
-  has_and_belongs_to_many :statuses
+  has_many :preview_cards_statuses, dependent: :delete_all, inverse_of: :preview_card
+  has_many :statuses, through: :preview_cards_statuses
+
   has_one :trend, class_name: 'PreviewCardTrend', inverse_of: :preview_card, dependent: :destroy
 
   has_attached_file :image, processors: [:thumbnail, :blurhash_transcoder], styles: ->(f) { image_styles(f) }, convert_options: { all: '-quality 90 +profile "!icc,*" +set date:modify +set date:create +set date:timestamp' }, validate_media_type: false
@@ -64,6 +66,9 @@ class PreviewCard < ApplicationRecord
 
   before_save :extract_dimensions, if: :link?
 
+  # This can be set by the status when retrieving the preview card using the join model
+  attr_accessor :original_url
+
   def appropriate_for_trends?
     link? && article? && title.present? && description.present? && image.present? && provider_name.present?
   end

app/models/preview_cards_status.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: preview_cards_statuses
+#
+#  preview_card_id :bigint(8)        not null
+#  status_id       :bigint(8)        not null
+#  url             :string
+#
+class PreviewCardsStatus < ApplicationRecord
+  # Composite primary keys are not properly supported in Rails. However,
+  # we shouldn't need this anyway...
+  self.primary_key = nil
+
+  belongs_to :preview_card
+  belongs_to :status
+end

app/models/status.rb

@@ -79,8 +79,8 @@ class Status < ApplicationRecord
   has_many :local_bookmarked, -> { merge(Account.local) }, through: :bookmarks, source: :account
 
   has_and_belongs_to_many :tags
-  has_and_belongs_to_many :preview_cards
 
+  has_one :preview_cards_status, inverse_of: :status # Because of a composite primary key, the dependent option cannot be used
   has_one :notification, as: :activity, dependent: :destroy
   has_one :status_stat, inverse_of: :status
   has_one :poll, inverse_of: :status, dependent: :destroy
@@ -142,24 +142,25 @@ class Status < ApplicationRecord
   # The `prepend: true` option below ensures this runs before
   # the `dependent: destroy` callbacks remove relevant records
   before_destroy :unlink_from_conversations!, prepend: true
+  before_destroy :reset_preview_card!
 
   cache_associated :application,
                    :media_attachments,
                    :conversation,
                    :status_stat,
                    :tags,
-                   :preview_cards,
                    :preloadable_poll,
+                   preview_cards_status: [:preview_card],
                    account: [:account_stat, user: :role],
                    active_mentions: { account: :account_stat },
                    reblog: [
                      :application,
                      :tags,
-                     :preview_cards,
                      :media_attachments,
                      :conversation,
                      :status_stat,
                      :preloadable_poll,
+                     preview_cards_status: [:preview_card],
                      account: [:account_stat, user: :role],
                      active_mentions: { account: :account_stat },
                    ],
@@ -226,7 +227,11 @@ class Status < ApplicationRecord
   end
 
   def preview_card
-    preview_cards.first
+    preview_cards_status&.preview_card&.tap { |x| x.original_url = preview_cards_status.url }
+  end
+
+  def reset_preview_card!
+    PreviewCardsStatus.where(status_id: id).delete_all
   end
 
   def hidden?
@@ -244,7 +249,7 @@ class Status < ApplicationRecord
   end
 
   def with_preview_card?
-    preview_cards.any?
+    preview_cards_status.present?
   end
 
   def with_poll?

app/models/trends/links.rb

@@ -54,9 +54,7 @@ class Trends::Links < Trends::Base
                   !(original_status.account.silenced? || status.account.silenced?) &&
                   !(original_status.spoiler_text? || original_status.sensitive?)
 
-    original_status.preview_cards.each do |preview_card|
-      add(preview_card, status.account_id, at_time) if preview_card.appropriate_for_trends?
-    end
+    add(original_status.preview_card, status.account_id, at_time) if original_status.preview_card&.appropriate_for_trends?
   end
 
   def add(preview_card, account_id, at_time = Time.now.utc)