Cleanup relayables where the signature is missing

When we should have the signature but don't have it, the user data
export fails. There are a few comments from back in 2011 where the
signature is missing.

Also some podmins maybe messed with signatures in their database, which
would also break the exports now.

closes #7637

Changelog.md

@@ -27,6 +27,7 @@
 * Fix export not downloadable because the filename was resetted on access [#7622](https://github.com/diaspora/diaspora/pull/7622)
 * Delete invalid oEmbed caches with binary titles [#7620](https://github.com/diaspora/diaspora/pull/7620)
 * Delete invalid diaspora IDs from friendica [#7630](https://github.com/diaspora/diaspora/pull/7630)
+* Cleanup relayables where the signature is missing [#7637](https://github.com/diaspora/diaspora/pull/7637)
 
 ## Features
 * Ask for confirmation when leaving a submittable comment field [#7530](https://github.com/diaspora/diaspora/pull/7530)

db/migrate/20171009232054_cleanup_relayables_without_signature.rb

+# frozen_string_literal: true
+
+class CleanupRelayablesWithoutSignature < ActiveRecord::Migration[5.1]
+  class Comment < ApplicationRecord
+    belongs_to :commentable, polymorphic: true
+
+    before_destroy do
+      Like.where(target_type: "Comment", target_id: id).destroy_all
+      ActsAsTaggableOn::Tagging.where(taggable_type: "Comment", taggable_id: id).destroy_all
+    end
+
+    after_destroy do
+      commentable.update_comments_counter
+    end
+  end
+
+  class Like < ApplicationRecord
+    belongs_to :target, polymorphic: true
+
+    has_one :signature, class_name: "LikeSignature", dependent: :delete
+
+    after_destroy do
+      target.update_likes_counter
+    end
+  end
+
+  class PollParticipation < ApplicationRecord
+    belongs_to :poll_answer, counter_cache: :vote_count
+  end
+
+  def up
+    cleanup_comments
+    cleanup_likes
+    cleanup_poll_participations
+  end
+
+  def cleanup_comments
+    Comment.joins("INNER JOIN posts as post ON post.id = comments.commentable_id AND " \
+                  "comments.commentable_type = 'Post'")
+           .joins("INNER JOIN people as comment_author ON comment_author.id = comments.author_id")
+           .joins("INNER JOIN people as post_author ON post_author.id = post.author_id")
+           .where("comment_author.owner_id IS NULL AND post_author.owner_id IS NOT NULL " \
+                  "AND NOT EXISTS(" \
+                    "SELECT NULL FROM comment_signatures WHERE comment_signatures.comment_id = comments.id" \
+                  ")")
+           .destroy_all
+  end
+
+  def cleanup_likes
+    Like.joins("INNER JOIN posts as post ON post.id = likes.target_id AND likes.target_type = 'Post'")
+        .joins("INNER JOIN people as like_author ON like_author.id = likes.author_id")
+        .joins("INNER JOIN people as post_author ON post_author.id = post.author_id")
+        .where("like_author.owner_id IS NULL AND post_author.owner_id IS NOT NULL " \
+               "AND NOT EXISTS(" \
+                 "SELECT NULL FROM like_signatures WHERE like_signatures.like_id = likes.id" \
+               ")")
+        .destroy_all
+    Like.joins("INNER JOIN comments as comment ON comment.id = likes.target_id AND likes.target_type = 'Comment'")
+        .joins("INNER JOIN posts as post ON post.id = comment.commentable_id AND comment.commentable_type = 'Post'")
+        .joins("INNER JOIN people as like_author ON like_author.id = likes.author_id")
+        .joins("INNER JOIN people as post_author ON post_author.id = post.author_id")
+        .where("like_author.owner_id IS NULL AND post_author.owner_id IS NOT NULL " \
+               "AND NOT EXISTS(" \
+                 "SELECT NULL FROM like_signatures WHERE like_signatures.like_id = likes.id" \
+               ")")
+        .destroy_all
+  end
+
+  def cleanup_poll_participations
+    PollParticipation.joins("INNER JOIN polls as poll ON poll.id = poll_participations.poll_id")
+                     .joins("INNER JOIN posts as post ON post.id = poll.status_message_id")
+                     .joins("INNER JOIN people as pp_author ON pp_author.id = poll_participations.author_id")
+                     .joins("INNER JOIN people as post_author ON post_author.id = post.author_id")
+                     .where("pp_author.owner_id IS NULL AND post_author.owner_id IS NOT NULL " \
+                            "AND NOT EXISTS(" \
+                              "SELECT NULL FROM poll_participation_signatures " \
+                              "WHERE poll_participation_signatures.poll_participation_id = poll_participations.id" \
+                            ")")
+                     .destroy_all
+  end
+end