fixes #785

app/assets/javascripts/related_tag.js

@@ -88,6 +88,9 @@
     var $dest = $("#related-tags");
     $dest.empty();
     
+    if (Danbooru.Cookie.get("recent_tags")) {
+      $dest.append(Danbooru.RelatedTag.build_html("recent", Danbooru.RelatedTag.recent_tags()));
+    }
     if (Danbooru.RelatedTag.favorite_tags().length) {
       $dest.append(Danbooru.RelatedTag.build_html("favorite", Danbooru.RelatedTag.favorite_tags()));
     }
@@ -108,6 +111,17 @@
     }
   }
   
+  Danbooru.RelatedTag.recent_tags = function() {
+    var string = Danbooru.Cookie.get("recent_tags");
+    if (string && string.length) {
+      return $.map(string.match(/\S+/g), function(x, i) {
+        return [[x, 0]];
+      });
+    } else {
+      return [];
+    }
+  }
+  
   Danbooru.RelatedTag.build_html = function(query, related_tags) {
     if (query === null || query === "") {
       return "";

app/controllers/posts_controller.rb

@@ -66,10 +66,10 @@ private
   end
 
   def save_recent_tags
-    if tag_query
+    if @post
-      tags = Tag.scan_tags(tag_query)
+      tags = Tag.scan_tags(@post.tag_string)
-      tags = TagAlias.to_aliased(tags) + Tag.scan_tags(session[:recent_tags])
+      tags = TagAlias.to_aliased(tags) + Tag.scan_tags(cookies[:recent_tags])
-      session[:recent_tags] = tags.uniq.slice(0, 40).join(" ")
+      cookies[:recent_tags] = tags.uniq.slice(0, 40).join(" ")
     end
   end
 end