Handle reshares of deleted posts in OpenGraph tags generation code

app/helpers/open_graph_helper.rb

@@ -50,14 +50,21 @@ module OpenGraphHelper
   end
 
   def og_page_post_tags(post)
-    [
+    tags = og_common_tags
-      *og_common_tags,
+
+    
+    if post.message
+      tags.concat [
+        *tags,
         og_type("#{og_namespace}:frame"),
         og_title(post_page_title(post, :length => 140)),
         og_url(post_url(post)),
         og_image(post),
         og_description(post.message.plain_text_without_markdown truncate: 1000)
-    ].join("\n").html_safe
+      ]
+    end
+    
+    tags.join("\n").html_safe
   end
 
   def og_prefix

spec/helpers/open_graph_helper_spec.rb

@@ -1,6 +1,21 @@
 require 'spec_helper'
 
 describe OpenGraphHelper, :type => :helper do
+  describe 'og_page_post_tags' do
+    it 'handles a reshare of a deleted post' do
+      reshare = FactoryGirl.build(:reshare, root: nil, id: 123)
+
+      expect {
+        helper.og_page_post_tags(reshare)
+      }.to_not raise_error
+    end
+
+    it 'handles a normal post' do
+      post = FactoryGirl.create(:status_message)
+      expect(helper.og_page_post_tags(post)).to include helper.og_url(post_url(post))
+    end
+  end
+
   describe 'og_html' do
     scenarios = {
       "article" => {