Bind aggregates over scoped tags to their subtree

CccConventions::TAG_SCOPES maps "update" and "pressemitteilung" to /updates
and "disclosure" to /disclosure. Page.aggregate applies the mapping, so an
aggregate over one of those tags is bounded by its subtree regardless of what
the shortcode says. Tags stay unrestricted; positions are publish-gated.

Both RSS actions call Page.aggregate rather than repeating its tag join.

Empty feeds no longer crash: Atom falls back to the current time for the
required <updated>, and the optional dc:date is omitted.

9 files changed, 80 insertions, 38 deletions

diff --git a/app/controllers/rss_controller.rb b/app/controllers/rss_controller.rb
index 655ccba4..c2149d90 100644
--- a/app/controllers/rss_controller.rb
+++ b/app/controllers/rss_controller.rb
@@ -1,19 +1,12 @@
 class RssController < ApplicationController
   
   before_action :get_host
-  
+
   def updates
     expires_in 31.minutes, :public => true
-    
     I18n.locale = I18n.default_locale
-  
-    @items = Page.heads
-      .joins("JOIN taggings ON taggings.taggable_id = pages.id
-            AND taggings.taggable_type = 'Page'
-            AND taggings.context = 'tags'")
-      .joins("JOIN tags ON tags.id = taggings.tag_id")
-      .where("LOWER(tags.name) = ?", "update")
-      .order("published_at DESC").limit(20)
+
+    @items = feed_items("update")
 
     respond_to do |format|
       format.xml {}
@@ -23,16 +16,10 @@ class RssController < ApplicationController
 
   def tag_updates
     expires_in 31.minutes, :public => true
-
     I18n.locale = I18n.default_locale
-    @tag  = params[:tag]
-    @items = Page.heads
-      .joins("JOIN taggings ON taggings.taggable_id = pages.id
-          AND taggings.taggable_type = 'Page'
-          AND taggings.context = 'tags'")
-      .joins("JOIN tags ON tags.id = taggings.tag_id")
-      .where("LOWER(tags.name) = ?", @tag.downcase)
-      .order("published_at DESC").limit(20)
+
+    @tag   = params[:tag]
+    @items = feed_items(@tag)
 
     respond_to do |format|
       format.xml {}
@@ -40,7 +27,14 @@ class RssController < ApplicationController
   end
 
   protected
-    
+
+    def feed_items tag
+      Page.aggregate(:tags => tag.to_s.downcase,
+                     :limit => 20,
+                     :order_by => "published_at",
+                     :order_direction => "DESC")
+    end
+
     def get_host
       @host = request.protocol + request.host_with_port
     end
diff --git a/app/helpers/content_helper.rb b/app/helpers/content_helper.rb
index 57f8c960..9d52c110 100644
--- a/app/helpers/content_helper.rb
+++ b/app/helpers/content_helper.rb
@@ -123,7 +123,7 @@ module ContentHelper
         sanitize(content, :attributes => cccms_attributes)
       end
 
-    rescue
+    rescue => e
       Rails.logger.error("aggregate shortcode failed on page #{@page&.id}: #{e.class}: #{e.message}")
       fallback = content.sub(/\[aggregate[^\]]*\]/, "")
       fallback = sanitize(fallback, :attributes => cccms_attributes)
diff --git a/app/models/page.rb b/app/models/page.rb
index cf003f74..a66527da 100644
--- a/app/models/page.rb
+++ b/app/models/page.rb
@@ -61,7 +61,7 @@ class Page < ApplicationRecord
     unless options[:tags].blank?
       tag_names = options[:tags].gsub(/\s/, ",").split(",").map(&:strip).map(&:downcase).uniq.reject(&:blank?)
 
-      unless tag_names.empty?
+    unless tag_names.empty?
         scope = scope
           .joins("JOIN taggings ON taggings.taggable_id = pages.id
                   AND taggings.taggable_type = 'Page'
@@ -71,6 +71,11 @@ class Page < ApplicationRecord
           .group("pages.id")
           .having("COUNT(DISTINCT tags.id) = ?", tag_names.length)
       end
+
+      CccConventions::TAG_SCOPES.values_at(*tag_names).compact.uniq.each do |root|
+        scope = scope.where("nodes.unique_name = ? OR nodes.unique_name LIKE ?",
+                            root, "#{root}/%")
+      end
     end
 
     if options[:node] && options[:children] == "direct"
diff --git a/app/views/rss/updates.rdf.builder b/app/views/rss/updates.rdf.builder
index b02d34ff..b4fecdb0 100644
--- a/app/views/rss/updates.rdf.builder
+++ b/app/views/rss/updates.rdf.builder
@@ -6,7 +6,7 @@ xml.tag!("rdf:RDF", "xmlns:rdf" => "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
     xml.title("Chaos Computer Club: Updates")
     xml.link("https://www.ccc.de")
     xml.description("Kabelsalat ist gesund.")
-    xml.tag!("dc:date", @items.first.published_at.xmlschema)
+    xml.tag!("dc:date", @items.first&.published_at&.xmlschema) if @items.any?
   end
 
   xml.image( "rdf:about" => "https://www.ccc.de/images/chaosknoten.gif") do
diff --git a/app/views/rss/updates.xml.builder b/app/views/rss/updates.xml.builder
index 27845c4c..f261de89 100644
--- a/app/views/rss/updates.xml.builder
+++ b/app/views/rss/updates.xml.builder
@@ -4,7 +4,7 @@ xml.feed(:xmlns => "http://www.w3.org/2005/Atom", "xml:base" => @host) do
   xml.title("Chaos Computer Club Updates")
   xml.link(:href => "https://www.ccc.de/")
   xml.link(:rel => "self", :href => "#{@host}/rss/updates.xml")
-  xml.updated(@items.first.published_at.xmlschema)
+  xml.updated((@items.first&.published_at || Time.now).xmlschema)
   xml.author do
     xml.name("Chaos Computer Club e.V.")
   end
diff --git a/lib/ccc_conventions.rb b/lib/ccc_conventions.rb
index b840dee2..52549c9e 100644
--- a/lib/ccc_conventions.rb
+++ b/lib/ccc_conventions.rb
@@ -52,4 +52,14 @@ module CccConventions
       hint:         "Automatically created under the Chaostreffs overview page, gets tag \"chaostreff-detail\", and uses the chapter detail template."
     }
   }.freeze
+
+  # Tags whose aggregates are forced into a subtree. Editors may apply any
+  # tag anywhere, but a page tagged "update" outside /updates will never
+  # appear in the front-page widget or the RSS feed, because every aggregate
+  # over that tag is scoped here rather than in the shortcode.
+  TAG_SCOPES = {
+    "update"           => "updates",
+    "pressemitteilung" => "updates",
+    "disclosure"       => "disclosure"
+  }.freeze
 end
diff --git a/test/controllers/content_controller_test.rb b/test/controllers/content_controller_test.rb
index 5bb02f3d..39fe276b 100644
--- a/test/controllers/content_controller_test.rb
+++ b/test/controllers/content_controller_test.rb
@@ -239,17 +239,16 @@ class ContentControllerTest < ActionController::TestCase
     end
 
     def fill_pages_with_content
-      d1 = find_or_create_draft(@first_child, @user1)
-      d1.title = "one"
-      d1.tag_list = "update"
-      d1.save
-      @first_child.publish_draft!
+      updates = Node.root.children.find_by(:slug => "updates") ||
+                Node.root.children.create!(:slug => "updates")
 
-      d2 = find_or_create_draft(@second_child, @user1)
-      d2.title = "two"
-      d2.tag_list = "update"
-      d2.save
-      @second_child.publish_draft!
+      [["one", "aggregated_one"], ["two", "aggregated_two"]].each do |title, slug|
+        node  = updates.children.create!(:slug => slug)
+        draft = find_or_create_draft(node, @user1)
+        draft.title = title
+        draft.tag_list = "update"
+        draft.save
+        node.publish_draft!
+      end
     end
-
 end
diff --git a/test/controllers/rss_controller_test.rb b/test/controllers/rss_controller_test.rb
index 3f4b4fbf..cf50903a 100644
--- a/test/controllers/rss_controller_test.rb
+++ b/test/controllers/rss_controller_test.rb
@@ -5,7 +5,9 @@ class RssControllerTest < ActionController::TestCase
   def setup
     @user = User.create :login => 'rsstest', :email => 'rsstest@example.com',
                         :password => 'foobar', :password_confirmation => 'foobar'
-    @node = Node.root.children.create! :slug => 'rss_test_node'
+    updates = Node.root.children.find_by(:slug => "updates") ||
+              Node.root.children.create!(:slug => "updates")
+    @node = updates.children.create! :slug => 'rss_test_node'
     draft = find_or_create_draft(@node, @user)
     draft.title = "RSS Update Article"
     draft.tag_list = "update"
@@ -31,4 +33,20 @@ class RssControllerTest < ActionController::TestCase
     assert assigns(:items).length <= 20
   end
 
+  test "the update feed excludes a page tagged update outside /updates" do
+    updates = Node.root.children.find_by(:slug => "updates")
+    inside  = updates.children.create!(:slug => "feed-inside")
+    outside = Node.root.children.create!(:slug => "feed-outside")
+
+    [inside, outside].each do |node|
+      node.reload.draft.update!(:title => node.slug, :tag_list => "update")
+      node.publish_draft!
+    end
+
+    get :updates, params: { :format => :xml }
+
+    assert_response :success
+    assert_includes     @response.body, "feed-inside"
+    assert_not_includes @response.body, "feed-outside"
+  end
 end
diff --git a/test/models/page_test.rb b/test/models/page_test.rb
index 98a00d21..395b6315 100644
--- a/test/models/page_test.rb
+++ b/test/models/page_test.rb
@@ -9,8 +9,9 @@ class PageTest < ActiveSupport::TestCase
   
   def test_aggregation
     # Create two nodes and move them beneath the root node
-    n1 = Node.root.children.create! :slug => "one"
-    n2 = Node.root.children.create! :slug => "two"
+    updates = Node.root.children.create! :slug => "updates"
+    n1 = updates.children.create! :slug => "one"
+    n2 = updates.children.create! :slug => "two"
     
     # get the drafts and assign a user to it
     assert_not_nil d1 = find_or_create_draft(n1, @user1)
@@ -409,4 +410,19 @@ class PageTest < ActiveSupport::TestCase
     page.reload
     assert page.update(:abstract => "still saveable")
   end
+
+  test "an aggregate over a scoped tag ignores pages outside that subtree" do
+    updates = Node.root.children.create!(:slug => "updates")
+    inside  = updates.children.create!(:slug => "inside-post")
+    outside = Node.root.children.create!(:slug => "outside-post")
+
+    [inside, outside].each do |node|
+      node.reload.draft.update!(:title => node.slug, :tag_list => "update")
+      node.publish_draft!
+    end
+
+    names = Page.aggregate({ :tags => "update" }).map { |p| p.node.unique_name }
+    assert_includes     names, "updates/inside-post"
+    assert_not_includes names, "outside-post"
+  end
 end