diff --git a/app/models/post.rb b/app/models/post.rb
index f659684cbb4..20b3d9d7fd8 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -51,9 +51,9 @@ class Post < ActiveRecord::Base
   scope :public_posts, -> { joins(:topic).where('topics.archetype <> ?', Archetype.private_message) }
   scope :private_posts, -> { joins(:topic).where('topics.archetype = ?', Archetype.private_message) }
   scope :with_topic_subtype, ->(subtype) { joins(:topic).where('topics.subtype = ?', subtype) }
-  
+
   delegate :username, to: :user
-  
+
   def self.hidden_reasons
     @hidden_reasons ||= Enum.new(:flag_threshold_reached, :flag_threshold_reached_again, :new_user_spam_threshold_reached)
   end
diff --git a/app/models/post_analyzer.rb b/app/models/post_analyzer.rb
index bfce07133ae..77b1b906a5e 100644
--- a/app/models/post_analyzer.rb
+++ b/app/models/post_analyzer.rb
@@ -75,7 +75,7 @@ class PostAnalyzer
       begin
         uri = URI.parse(u)
         host = uri.host
-        @linked_hosts[host] ||= 1
+        @linked_hosts[host] ||= 1 unless host.nil?
       rescue URI::InvalidURIError
         # An invalid URI does not count as a raw link.
         next
@@ -90,10 +90,10 @@ class PostAnalyzer
     return [] unless @raw.present?
     return @raw_links if @raw_links.present?
 
-    # Don't include @mentions in the link count
     @raw_links = []
 
     cooked_document.search("a").each do |l|
+      # Don't include @mentions in the link count
       next if l.attributes['href'].nil? || link_is_a_mention?(l)
       url = l.attributes['href'].to_s
       @raw_links << url
diff --git a/lib/pretty_text.rb b/lib/pretty_text.rb
index a07fcc5f608..7f9248d26ee 100644
--- a/lib/pretty_text.rb
+++ b/lib/pretty_text.rb
@@ -192,7 +192,7 @@ module PrettyText
         else
           l["rel"] = "nofollow"
         end
-      rescue URI::InvalidURIError
+      rescue URI::InvalidURIError, URI::InvalidComponentError
         # add a nofollow anyway
         l["rel"] = "nofollow"
       end
diff --git a/lib/topic_creator.rb b/lib/topic_creator.rb
index 62202f4c6a9..7356c8b81f0 100644
--- a/lib/topic_creator.rb
+++ b/lib/topic_creator.rb
@@ -55,7 +55,7 @@ class TopicCreator
 
     category = find_category
 
-    @guardian.ensure_can_create!(Topic,category)
+    @guardian.ensure_can_create!(Topic, category)
 
     topic_params[:category_id] = category.id if category.present?
 
diff --git a/vendor/assets/javascripts/better_markdown.js b/vendor/assets/javascripts/better_markdown.js
index fc1a9170123..ec7a3ed21a2 100644
--- a/vendor/assets/javascripts/better_markdown.js
+++ b/vendor/assets/javascripts/better_markdown.js
@@ -437,11 +437,15 @@
   };
 
   function escapeHTML( text ) {
-    return text.replace( /&/g, "&amp;" )
-               .replace( /</g, "&lt;" )
-               .replace( />/g, "&gt;" )
-               .replace( /"/g, "&quot;" )
-               .replace( /'/g, "&#39;" );
+    if (text && text.length > 0) {
+      return text.replace( /&/g, "&amp;" )
+                 .replace( /</g, "&lt;" )
+                 .replace( />/g, "&gt;" )
+                 .replace( /"/g, "&quot;" )
+                 .replace( /'/g, "&#39;" );
+    } else {
+      return "";
+    }
   }
 
   function render_tree( jsonml ) {