[Posts] Allow guidelines flag in more cases for priv+

app/models/post.rb

@@ -1750,4 +1750,10 @@ class Post < ApplicationRecord
     linked_artists ||= tags.select { |t| t.category == Tag.categories.artist }.filter_map(&:artist)
     linked_artists.select { |artist| artist.linked_user_id == uploader_id }
   end
+
+  def flaggable_for_guidelines?
+    return true if is_pending?
+    return true if CurrentUser.is_privileged? && !has_tag?("grandfathered_content") && created_at.after?("2015-01-01")
+    return false
+  end
 end

app/models/post_flag.rb

@@ -188,7 +188,7 @@ class PostFlag < ApplicationRecord
       end
       errors.add(:parent_id, "cannot be set to the post being flagged") if parent_post.id == post.id
     when 'uploading_guidelines'
-      errors.add(:reason, "can only be used on pending posts") unless post.is_pending
+      errors.add(:reason, "cannot be used. The post is either not pending, or grandfathered") unless post.flaggable_for_guidelines?
     else
       errors.add(:reason, "is not one of the available choices") unless MAPPED_REASONS.key?(reason_name)
     end

app/views/post_flags/_new.html.erb

@@ -19,7 +19,7 @@
     <%= f.hidden_field :post_id %>
 
     <% Danbooru.config.flag_reasons.each do |flag_reason| %>
-      <% if flag_reason[:name] == "uploading_guidelines" && !@post.is_pending %>
+      <% if flag_reason[:name] == "uploading_guidelines" && !@post.flaggable_for_guidelines? %>
         <% next %>
       <% end %>
 

test/unit/post_flag_test.rb

@@ -43,7 +43,7 @@ class PostFlagTest < ActiveSupport::TestCase
           @post_flag = create(:post_flag, post: @post, reason_name: "uploading_guidelines")
         end
       end
-      assert_match(/can only be used on pending posts/, error.message)
+      assert_match(/not pending/, error.message)
 
       @post = create(:post, is_pending: true)
       as(@bob) do