7 files changed, 148 insertions, 57 deletions

diff --git a/app/models/page.rb b/app/models/page.rb
index 3240057f..c2dc227b 100644
--- a/app/models/page.rb
+++ b/app/models/page.rb
@@ -277,6 +277,12 @@ class Page < ApplicationRecord
 
     text_diffs.merge(
       address:       address_diff_against(other),
+      external_url:  { from: other.external_url, to: external_url,
+                       changed: external_url.presence != other.external_url.presence },
+      published_at:  { from: other.published_at, to: published_at,
+                       changed: published_at != other.published_at },
+      user:          { from: other.user, to: user,
+                       changed: user_id != other.user_id },
       tags:          { added: tag_list.to_a - other.tag_list.to_a, removed: other.tag_list.to_a - tag_list.to_a },
       template_name: { from: other.template_name, to: template_name, changed: template_name != other.template_name },
       assets:        { added: assets.to_a - other.assets.to_a, removed: other.assets.to_a - assets.to_a }
diff --git a/app/views/revisions/diff.html.erb b/app/views/revisions/diff.html.erb
index 0fd9ccb9..25f5ad04 100644
--- a/app/views/revisions/diff.html.erb
+++ b/app/views/revisions/diff.html.erb
@@ -48,7 +48,6 @@
   </p>
 <% end %>
 
-
 <% if @available_layer_pairs.present? %>
   <div class="node_action_bar standalone_action_bar">
     <% @available_layer_pairs.each do |pair| %>
@@ -71,21 +70,88 @@
 <% end %>
 
 <div id="diffview">
-  <% current_summary = @locale_summary.find { |s| s[:locale] == @translation_locale } %>
-  <% if current_summary && !current_summary[:changed] %>
-    <% elsewhere = @locale_summary.select { |s| s[:changed] }.map { |s|
-         link_to s[:locale].to_s.upcase, diff_node_revisions_path(@node,
-           start_revision: params[:start_revision], end_revision: params[:end_revision],
-           view: @diff_view, translation_locale: s[:locale]) } %>
-    <p class="diff_unchanged diff_locale_pointer">
-      <% if elsewhere.any? %>
-        <%= t(".unchanged_here_html", :lang => @translation_locale.to_s.upcase,
-              :others => safe_join(elsewhere, ", ")) %>
-      <% else %>
-        <%= t(".unchanged_anywhere") %>
+  <% meta_changed = @diff[:address][:changed] || @diff[:external_url][:changed] ||
+                    @diff[:template_name][:changed] ||
+                    @diff[:published_at][:changed] || @diff[:user][:changed] ||
+                    @diff[:tags][:added].any?   || @diff[:tags][:removed].any? ||
+                    @diff[:assets][:added].any? || @diff[:assets][:removed].any? %>
+
+  <div class="diff_preamble">
+    <div class="diff_meta">
+      <% unless meta_changed %>
+        <p class="diff_unchanged"><%= t(".no_metadata_change") %></p>
+      <% end %>
+
+      <% if @diff[:address][:changed] %>
+        <h3><%= t(".address") %></h3>
+        <p>
+          <del><%= @diff[:address][:from] || t(".none_marker") %></del>
+          <ins><%= @diff[:address][:to] || t(".none_marker") %></ins>
+        </p>
+      <% end %>
+
+      <% if @diff[:external_url][:changed] %>
+        <h3><%= Page.human_attribute_name(:external_url) %></h3>
+        <p>
+          <del><%= @diff[:external_url][:from].presence || t(".none_marker") %></del>
+          <ins><%= @diff[:external_url][:to].presence || t(".none_marker") %></ins>
+        </p>
+      <% end %>
+
+      <% if @diff[:published_at][:changed] %>
+        <h3><%= Page.human_attribute_name(:published_at) %></h3>
+        <p>
+          <del><%= @diff[:published_at][:from] ? admin_datetime(@diff[:published_at][:from]) : t(".none_marker") %></del>
+          <ins><%= @diff[:published_at][:to] ? admin_datetime(@diff[:published_at][:to]) : t(".none_marker") %></ins>
+        </p>
       <% end %>
-    </p>
-  <% end %>
+
+      <% if @diff[:user][:changed] %>
+        <h3><%= Page.human_attribute_name(:user) %></h3>
+        <p>
+          <del><%= @diff[:user][:from]&.login || t(".none_marker") %></del>
+          <ins><%= @diff[:user][:to]&.login || t(".none_marker") %></ins>
+        </p>
+      <% end %>
+
+      <% if @diff[:tags][:added].any? || @diff[:tags][:removed].any? %>
+        <h3><%= Page.human_attribute_name(:tag_list) %></h3>
+        <ul class="diff_set_list">
+          <% @diff[:tags][:added].each do |tag| %><li><ins><%= tag %></ins></li><% end %>
+          <% @diff[:tags][:removed].each do |tag| %><li><del><%= tag %></del></li><% end %>
+        </ul>
+      <% end %>
+
+      <% if @diff[:template_name][:changed] %>
+        <h3><%= Page.human_attribute_name(:template_name) %></h3>
+        <p><del><%= @diff[:template_name][:from] || t(".none_marker") %></del> <ins><%= @diff[:template_name][:to] || t(".none_marker") %></ins></p>
+      <% end %>
+
+      <% if @diff[:assets][:added].any? || @diff[:assets][:removed].any? %>
+        <h3><%= Page.human_attribute_name(:assets) %></h3>
+        <ul class="diff_set_list">
+          <% @diff[:assets][:added].each do |asset| %><li><ins><%= asset.upload_file_name %></ins></li><% end %>
+          <% @diff[:assets][:removed].each do |asset| %><li><del><%= asset.upload_file_name %></del></li><% end %>
+        </ul>
+      <% end %>
+    </div>
+
+    <% current_summary = @locale_summary.find { |s| s[:locale] == @translation_locale } %>
+    <% if current_summary && !current_summary[:changed] %>
+      <% elsewhere = @locale_summary.select { |s| s[:changed] }.map { |s|
+           link_to s[:locale].to_s.upcase, diff_node_revisions_path(@node,
+             start_revision: params[:start_revision], end_revision: params[:end_revision],
+             view: @diff_view, translation_locale: s[:locale]) } %>
+      <p class="diff_unchanged diff_locale_pointer">
+        <% if elsewhere.any? %>
+          <%= t(".unchanged_here_html", :lang => @translation_locale.to_s.upcase,
+                :others => safe_join(elsewhere, ", ")) %>
+        <% else %>
+          <%= t(".unchanged_anywhere") %>
+        <% end %>
+      </p>
+    <% end %>
+  </div>
 
   <% if @diff_view == :side_by_side %>
     <div class="diff_side_by_side">
@@ -114,41 +180,4 @@
     <h3><%= Page.human_attribute_name(:body) %></h3>
     <%= raw @diff[:body] %>
   <% end %>
-
-  <h3><%= t(".address") %></h3>
-  <% if @diff[:address][:changed] %>
-    <p>
-      <del><%= @diff[:address][:from] || t(".none_marker") %></del>
-      <ins><%= @diff[:address][:to] || t(".none_marker") %></ins>
-    </p>
-  <% else %>
-    <p class="diff_unchanged"><%= t(".no_change") %></p>
-  <% end %>
-
-  <h3><%= Page.human_attribute_name(:tag_list) %></h3>
-  <% if @diff[:tags][:added].empty? && @diff[:tags][:removed].empty? %>
-    <p class="diff_unchanged"><%= t(".no_change") %></p>
-  <% else %>
-    <ul class="diff_set_list">
-      <% @diff[:tags][:added].each do |tag| %><li><ins><%= tag %></ins></li><% end %>
-      <% @diff[:tags][:removed].each do |tag| %><li><del><%= tag %></del></li><% end %>
-    </ul>
-  <% end %>
-
-  <h3><%= Page.human_attribute_name(:template_name) %></h3>
-  <% if @diff[:template_name][:changed] %>
-    <p><del><%= @diff[:template_name][:from] || t(".none_marker") %></del> <ins><%= @diff[:template_name][:to] || t(".none_marker") %></ins></p>
-  <% else %>
-    <p class="diff_unchanged"><%= t(".no_change") %></p>
-  <% end %>
-
-  <h3><%= Page.human_attribute_name(:assets) %></h3>
-  <% if @diff[:assets][:added].empty? && @diff[:assets][:removed].empty? %>
-    <p class="diff_unchanged"><%= t(".no_change") %></p>
-  <% else %>
-    <ul class="diff_set_list">
-      <% @diff[:assets][:added].each do |asset| %><li><ins><%= asset.upload_file_name %></ins></li><% end %>
-      <% @diff[:assets][:removed].each do |asset| %><li><del><%= asset.upload_file_name %></del></li><% end %>
-    </ul>
-  <% end %>
 </div>
diff --git a/config/locales/de.yml b/config/locales/de.yml
index 2aec7bfa..3f2eb0ab 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -106,6 +106,9 @@ de:
         tag_list: "Tags"
         template_name: "Template"
         assets: "Anhänge"
+        external_url: "Externe Homepage"
+        published_at: "Veröffentlichungsdatum"
+        user: "Autor"
       menu_item:
         node_id: "Node-ID"
         path: "Pfad"
@@ -744,7 +747,7 @@ de:
       revisions_link: "Alle Revisionen"
       compare_numbered: "Stattdessen zwei nummerierte Revisionen vergleichen"
       none_marker: "(keins)"
-      no_change: "Keine Änderung."
+      no_metadata_change: "Keine Änderungen an den Metadaten."
       unchanged_here_html: "Keine Änderung in der Übersetzung %{lang} zwischen diesen Revisionen — geändert wurde %{others}."
       unchanged_anywhere: "Zwischen diesen Revisionen wurde keine Übersetzung geändert."
       address: "Adresse"
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 965906df..e8428f69 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -57,6 +57,9 @@ en:
         tag_list: "Tags"
         template_name: "Template"
         assets: "Assets"
+        external_url: "External homepage"
+        published_at: "Publication date"
+        user: "Author"
       menu_item:
         node_id: "Node Id"
         path: "Path"
@@ -712,7 +715,7 @@ en:
       revisions_link: "All revisions"
       compare_numbered: "Compare two numbered revisions instead"
       none_marker: "(none)"
-      no_change: "No change."
+      no_metadata_change: "No metadata changes."
       unchanged_here_html: "No change in the %{lang} translation between these revisions — %{others} changed."
       unchanged_anywhere: "No translation changed between these revisions."
       address: "Address"
diff --git a/public/stylesheets/admin.css b/public/stylesheets/admin.css
index 7951f667..b8a01112 100644
--- a/public/stylesheets/admin.css
+++ b/public/stylesheets/admin.css
@@ -799,6 +799,12 @@ table.revisions_table tr:hover {
   margin: 0;
 }
 
+.diff_preamble {
+  border-bottom: 1px solid var(--hairline);
+  margin-bottom: 1.5rem;
+  padding-bottom: 0.5rem;
+}
+
 .user_table {
   width: 100%;
   max-width: 44rem;
diff --git a/test/controllers/revisions_controller_test.rb b/test/controllers/revisions_controller_test.rb
index 34f00a4f..d9f49e58 100644
--- a/test/controllers/revisions_controller_test.rb
+++ b/test/controllers/revisions_controller_test.rb
@@ -151,19 +151,35 @@ class RevisionsControllerTest < ActionController::TestCase
     assert_select "input[type='hidden'][name='end_revision'][value='draft']"
   end
 
-  test "diffing two revisions also shows tag, template, and asset changes" do
+  test "diffing shows tag, template, external URL and asset changes" do
     login_as :quentin
     find_or_create_draft(@node, @user)
-    @node.draft.tag_list = "update"
-    @node.draft.save!
+    draft = @node.draft
+    draft.tag_list      = "update"
+    draft.template_name = "title_only"
+    draft.external_url  = "https://example.org/"
+    draft.save!
+    draft.related_assets.create!(:asset => Asset.create!(:name => "diffed",
+                                  :upload_file_name => "diffed.png",
+                                  :upload_content_type => "image/png"))
 
     post(:diff, params: { :node_id => @node.id, :start_revision => @node.pages.first.revision, :end_revision => @node.pages.last.revision })
     assert_response :success
     assert_select "h3", Page.human_attribute_name(:tag_list)
     assert_select "h3", Page.human_attribute_name(:template_name)
+    assert_select "h3", Page.human_attribute_name(:external_url)
     assert_select "h3", Page.human_attribute_name(:assets)
   end
 
+  test "a diff with no metadata changes says so once" do
+    login_as :quentin
+
+    post(:diff, params: { :node_id => @node.id, :start_revision => @node.pages.first.revision, :end_revision => @node.pages.last.revision })
+    assert_response :success
+    assert_select ".diff_meta .diff_unchanged"
+    assert_select ".diff_meta h3", false
+  end
+
   test "revisions#index links back to the node" do
     login_as :quentin
     get :index, params: { :node_id => @node.id }
diff --git a/test/models/page_test.rb b/test/models/page_test.rb
index b737e8b0..f095a7e1 100644
--- a/test/models/page_test.rb
+++ b/test/models/page_test.rb
@@ -302,6 +302,34 @@ class PageTest < ActiveSupport::TestCase
     assert_equal "title_only", diff[:template_name][:to]
   end
 
+  test "diff_against reports external URL, publication date and author changes" do
+    n = Node.root.children.create! :slug => "meta_diff_test"
+    d = find_or_create_draft(n, @user1)
+    d.external_url = "https://old.example.org/"
+    d.published_at = Time.utc(2026, 1, 1, 12, 0, 0)
+    d.save!
+    n.publish_draft!
+
+    new_author = User.where.not(:id => n.head.user_id).first
+    d2 = find_or_create_draft(n, @user1)
+    d2.external_url = "https://new.example.org/"
+    d2.published_at = Time.utc(2026, 3, 1, 12, 0, 0)
+    d2.user         = new_author
+    d2.save!
+
+    diff = d2.diff_against(n.head)
+
+    assert diff[:external_url][:changed]
+    assert_equal "https://old.example.org/", diff[:external_url][:from]
+    assert_equal "https://new.example.org/", diff[:external_url][:to]
+
+    assert diff[:published_at][:changed]
+    assert_equal Time.utc(2026, 3, 1, 12, 0, 0).to_i, diff[:published_at][:to].to_i
+
+    assert diff[:user][:changed]
+    assert_equal new_author.login, diff[:user][:to].login
+  end
+
   test "diff_against reports added and removed assets by filename" do
     n = Node.root.children.create! :slug => "asset_diff_test"
     d = find_or_create_draft(n, @user1)