Fix #5293: NoMethodError in sitemap when relation is empty.

app/views/robots/index.text.erb

@@ -74,11 +74,32 @@ Allow: /sitemap.xml
 Allow: /favicon.ico
 Allow: /favicon.svg
 
+<% if Artist.undeleted.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "artists") %>
+<% end %>
+
+<% if ForumTopic.undeleted.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "forum_topics") %>
+<% end %>
+
+<% if Pool.undeleted.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "pools") %>
+<% end %>
+
+<% if Post.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "posts") %>
+<% end %>
+
+<% if Tag.nonempty.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "tags") %>
+<% end %>
+
+<% if User.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "users") %>
+<% end %>
+
+<% if WikiPage.undeleted.exists? %>
 Sitemap: <%= sitemap_url(format: :xml, sitemap: "wiki_pages") %>
 <% end %>
+
+<% end %>

app/views/static/sitemap_index.xml.erb

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
 <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
-  <% 0.upto(@relation.maximum(:id) / @limit) do |page| %>
+  <% 0.upto(@relation.maximum(:id).to_i / @limit) do |page| %>
     <% lo = page * @limit %>
     <% hi = (page + 1) * @limit %>
     <% lastmod = @relation.where(id: lo..hi).maximum(:updated_at)&.iso8601 %>

test/functional/static_controller_test.rb

@@ -23,6 +23,12 @@ class StaticControllerTest < ActionDispatch::IntegrationTest
         assert_equal(1, response.parsed_body.css("sitemap loc").size)
       end
     end
+
+    should "work when the sitemap is empty" do
+      get sitemap_path(sitemap: "pools"), as: :xml
+
+      assert_response :success
+    end
   end
 
   context "dtext_help action" do