List all class ancestors

lib/rdoc/code_object/class_module.rb

@@ -711,6 +711,20 @@ def superclass=(superclass)
     @superclass = superclass
   end
 
+  ##
+  # Get all super classes of this class in an array. The last element might be
+  # a string if the name is unknown.
+
+  def super_classes
+    result = []
+    parent = self
+    while parent = parent.superclass
+      result << parent
+      return result if parent.is_a?(String)
+    end
+    result
+  end
+
   def to_s # :nodoc:
     if is_alias_for then
       "#{self.class.name} #{self.full_name} -> #{is_alias_for}"

lib/rdoc/generator/template/darkfish/_sidebar_parent.rhtml

@@ -1,11 +1,42 @@
-<%- if klass.type == 'class' then %>
+<%- if klass.type == 'class' && (ancestors = klass.super_classes).any? then %>
 <div id="parent-class-section" class="nav-section">
-  <h3>Parent</h3>
+  <h3>Ancestors</h3>
+  <% if ancestors.size > 1 %>
+    <% parent = ancestors.shift %>
+    <ul>
+      <li>
+        <details>
+          <summary>
+            <% if parent.is_a?(RDoc::NormalClass) %>
+              <a href="<%= klass.aref_to parent.path -%>"><%= parent.full_name -%></a>
+            <% else %>
+              <%= parent -%>
+            <% end %>
+          </summary>
 
-  <%- if klass.superclass and not String === klass.superclass then -%>
-  <p class="link"><a href="<%= klass.aref_to klass.superclass.path %>"><%= klass.superclass.full_name %></a>
-  <%- else -%>
-  <p class="link"><%= klass.superclass %>
-  <%- end -%>
+          <% for ancestor in ancestors %>
+            <ul>
+              <li>
+                <% if ancestor.is_a?(RDoc::NormalClass) %>
+                  <a href="<%= klass.aref_to ancestor.path -%>"><%= ancestor.full_name -%></a>
+                <% else %>
+                  <%= ancestor -%>
+                <% end %>
+          <% end %>
+
+          <% for ancestor in ancestors # Sorry, templates cannot be recursive %>
+              </li>
+            </ul>
+          <% end %>
+        </details>
+      </li>
+    </ul>
+  <% else %>
+    <%- if klass.superclass and not String === klass.superclass then -%>
+    <p class="link"><a href="<%= klass.aref_to klass.superclass.path %>"><%= klass.superclass.full_name %></a>
+    <%- else -%>
+    <p class="link"><%= klass.superclass %>
+    <%- end -%>
+  <% end %>
 </div>
 <%- end -%>

test/rdoc/test_rdoc_class_module.rb

@@ -1279,6 +1279,12 @@ def test_superclass
     assert_equal @c3_h1, @c3_h2.superclass
   end
 
+  def test_super_classes
+    rdoc_c3_h1 = @xref_data.find_module_named('C3::H1')
+    rdoc_object = @xref_data.find_module_named('Object')
+    assert_equal [rdoc_c3_h1, rdoc_object, "BasicObject"], @c3_h2.super_classes
+  end
+
   def test_update_aliases_class
     n1 = @xref_data.add_module RDoc::NormalClass, 'N1'
     n1_k2 = n1.add_module RDoc::NormalClass, 'N2'