FIX: permalink redirects should work on tag paths

app/controllers/application_controller.rb

@@ -329,6 +329,25 @@ class ApplicationController < ActionController::Base
     request.session_options[:skip] = true
   end
 
+  def permalink_redirect_or_not_found
+    url = request.fullpath
+    permalink = Permalink.find_by_url(url)
+
+    if permalink.present?
+      # permalink present, redirect to that URL
+      if permalink.external_url
+        redirect_to permalink.external_url, status: :moved_permanently
+      elsif permalink.target_url
+        redirect_to "#{Discourse::base_uri}#{permalink.target_url}", status: :moved_permanently
+      else
+        raise Discourse::NotFound
+      end
+    else
+      # redirect to 404
+      raise Discourse::NotFound
+    end
+  end
+
   private
 
     def locale_from_header

app/controllers/list_controller.rb

@@ -259,7 +259,7 @@ class ListController < ApplicationController
     parent_category_id = nil
     if parent_slug_or_id.present?
       parent_category_id = Category.query_parent_category(parent_slug_or_id)
-      redirect_or_not_found and return if parent_category_id.blank? && !id
+      permalink_redirect_or_not_found and return if parent_category_id.blank? && !id
     end
 
     @category = Category.query_category(slug_or_id, parent_category_id)
@@ -270,7 +270,7 @@ class ListController < ApplicationController
       (redirect_to category.url, status: 301) && return if category
     end
 
-    redirect_or_not_found and return if !@category
+    permalink_redirect_or_not_found and return if !@category
 
     @description_meta = @category.description_text
     raise Discourse::NotFound unless guardian.can_see?(@category)
@@ -349,23 +349,4 @@ class ListController < ApplicationController
     periods
   end
 
-  def redirect_or_not_found
-    url = request.fullpath
-    permalink = Permalink.find_by_url(url)
-
-    if permalink.present?
-      # permalink present, redirect to that URL
-      if permalink.external_url
-        redirect_to permalink.external_url, status: :moved_permanently
-      elsif permalink.target_url
-        redirect_to "#{Discourse::base_uri}#{permalink.target_url}", status: :moved_permanently
-      else
-        raise Discourse::NotFound
-      end
-    else
-      # redirect to 404
-      raise Discourse::NotFound
-    end
-  end
-
 end

app/controllers/tags_controller.rb

@@ -78,7 +78,7 @@ class TagsController < ::ApplicationController
       canonical_url "#{Discourse.base_url_no_prefix}#{public_send(url_method(params.slice(:category, :parent_category)))}"
 
       if @list.topics.size == 0 && params[:tag_id] != 'none' && !Tag.where(name: @tag_id).exists?
-        raise Discourse::NotFound
+        permalink_redirect_or_not_found
       else
         respond_with_list(@list)
       end
@@ -220,13 +220,13 @@ class TagsController < ::ApplicationController
         parent_category_id = nil
         if parent_slug_or_id.present?
           parent_category_id = Category.query_parent_category(parent_slug_or_id)
-          redirect_or_not_found and return if parent_category_id.blank?
+          category_redirect_or_not_found and return if parent_category_id.blank?
         end
 
         @filter_on_category = Category.query_category(slug_or_id, parent_category_id)
       end
 
-      redirect_or_not_found and return if !@filter_on_category
+      category_redirect_or_not_found and return if !@filter_on_category
 
       guardian.ensure_can_see!(@filter_on_category)
     end
@@ -305,7 +305,7 @@ class TagsController < ::ApplicationController
       options
     end
 
-    def redirect_or_not_found
+    def category_redirect_or_not_found
       # automatic redirects for renamed categories
       url = params[:parent_category] ? "c/#{params[:parent_category]}/#{params[:category]}" : "c/#{params[:category]}"
       permalink = Permalink.find_by_url(url)