#46

backend/app/controllers/posts_controller.rb

@@ -127,7 +127,7 @@ class PostsController < ApplicationController
 
     post = Post.new(title:, url:, thumbnail_base: nil, uploaded_user: current_user,
                     original_created_from:, original_created_before:)
-    post.thumbnail.attach(thumbnail)
+    post.thumbnail.attach(thumbnail) if thumbnail.present?
 
     ApplicationRecord.transaction do
       post.save!
@@ -149,8 +149,8 @@ class PostsController < ApplicationController
     render json: PostRepr.base(post), status: :created
   rescue ArgumentError => e
     render json: { errors: [e.message] }, status: :unprocessable_entity
-  rescue ActiveRecord::RecordInvalid
-    render json: { errors: post.errors.full_messages }, status: :unprocessable_entity
+  rescue ActiveRecord::RecordInvalid => e
+    render json: { errors: e.record.errors.full_messages }, status: :unprocessable_entity
   rescue Tag::NicoTagNormalisationError
     head :bad_request
   end
@@ -204,8 +204,8 @@ class PostsController < ApplicationController
     render json:, status: :ok
   rescue ArgumentError => e
     render json: { errors: [e.message] }, status: :unprocessable_entity
-  rescue ActiveRecord::RecordInvalid
-    render json: post.errors, status: :unprocessable_entity
+  rescue ActiveRecord::RecordInvalid => e
+    render json: { errors: e.record.errors.full_messages }, status: :unprocessable_entity
   rescue Tag::NicoTagNormalisationError
     head :bad_request
   end

backend/app/models/post.rb

@@ -56,7 +56,7 @@ class Post < ApplicationRecord
 
   def snapshot_tag_names = tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
 
-  def snapshot_parent_post_ids = parents.order(:parent_post_id).pluck(:parent_post_id)
+  def snapshot_parent_post_ids = parents.order(:id).pluck(:id)
 
   def related limit: nil
     ids = post_similarities.order(cos: :desc)