Fix rendering a differently-formatted partial after caching

actionpack/test/controller/caching_test.rb

@@ -173,6 +173,9 @@ class FunctionalCachingController < CachingController
     end
   end
 
+  def xml_fragment_cached_with_html_partial
+  end
+
   def formatted_fragment_cached
     respond_to do |format|
       format.html
@@ -308,6 +311,11 @@ CACHED
       @store.read("views/functional_caching/formatted_fragment_cached_with_variant:#{template_digest("functional_caching/formatted_fragment_cached_with_variant")}/fragment")
   end
 
+  def test_fragment_caching_with_html_partials_in_xml
+    get :xml_fragment_cached_with_html_partial, format: "*/*"
+    assert_response :success
+  end
+
   private
     def template_digest(name)
       ActionView::Digestor.digest(name: name, finder: @controller.lookup_context)

actionpack/test/fixtures/functional_caching/_formatted_partial.html.erb

@@ -0,0 +1 @@
+<p>Hello!</p>

actionpack/test/fixtures/functional_caching/xml_fragment_cached_with_html_partial.xml.builder

@@ -0,0 +1,5 @@
+cache do
+  xml.title "Hello!"
+end
+
+xml.body cdata_section(render("formatted_partial"))

actionview/lib/action_view/digestor.rb

@@ -45,9 +45,8 @@ module ActionView
       # Create a dependency tree for template named +name+.
       def tree(name, finder, partial = false, seen = {})
         logical_name = name.gsub(%r|/_|, "/")
-        finder.formats = [finder.rendered_format] if finder.rendered_format
 
-        if template = finder.disable_cache { finder.find_all(logical_name, [], partial, []).first }
+        if template = find_template(finder, logical_name, [], partial, [])
           finder.rendered_format ||= template.formats.first
 
           if node = seen[template.identifier] # handle cycles in the tree
@@ -69,6 +68,17 @@ module ActionView
           seen[name] ||= Missing.new(name, logical_name, nil)
         end
       end
+
+      private
+        def find_template(finder, *args)
+          finder.disable_cache do
+            if format = finder.rendered_format
+              finder.find_all(*args, formats: [format]).first || finder.find_all(*args).first
+            else
+              finder.find_all(*args).first
+            end
+          end
+        end
     end
 
     class Node