fixes #2428

app/controllers/comments_controller.rb

@@ -56,7 +56,7 @@ class CommentsController < ApplicationController
   def destroy
     @comment = Comment.find(params[:id])
     check_privilege(@comment)
-    @comment.destroy
+    @comment.delete!
     respond_with(@comment) do |format|
       format.js
     end

app/models/comment.rb

@@ -171,6 +171,10 @@ class Comment < ActiveRecord::Base
   def hidden_attributes
     super + [:body_index]
   end
+
+  def delete!
+    update_attribute(:is_deleted, true)
+  end
 end
 
 Comment.connection.extend(PostgresExtensions)

app/views/comments/destroy.js.erb

@@ -1 +1 @@
-$(".comment[data-comment-id=<%= @comment.id %>]").remove();
+$(".comment[data-comment-id=<%= @comment.id %>] div.author h1").append(" (deleted)");

app/views/comments/partials/show/_comment.html.erb

@@ -1,6 +1,12 @@
-<article class="comment" data-post-id="<%= comment.post_id %>" data-comment-id="<%= comment.id %>" data-score="<%= comment.score %>" data-creator="<%= comment.creator.name %>">
+<% if CurrentUser.is_moderator? || !comment.is_deleted? %>
+  <article class="comment" data-post-id="<%= comment.post_id %>" data-comment-id="<%= comment.id %>" data-score="<%= comment.score %>" data-creator="<%= comment.creator.name %>">
     <div class="author">
-    <h1><%= link_to_user comment.creator %></h1>
+      <h1>
+        <%= link_to_user comment.creator %>
+        <% if comment.is_deleted? %>
+          (deleted)
+        <% end %>
+      </h1>
       <p>
         <%= time_ago_in_words_tagged(comment.created_at) %>
       </p>
@@ -33,4 +39,5 @@
       <% end %>
     </div>
     <div class="clearfix"></div>
-</article>
+  </article>
+<% end %>

db/migrate/20150705014135_add_is_deleted_to_comments.rb

@@ -0,0 +1,6 @@
+class AddIsDeletedToComments < ActiveRecord::Migration
+  def change
+    execute "set statement_timeout = 0"
+    add_column :comments, :is_deleted, :boolean, :null => false, :default => false
+  end
+end