Cached collections only work if there is one template

Cached collections only work if there is one template.  If there are
more than one templates, the caching mechanism doesn't have a key.

1 files changed, 11 insertions, 0 deletions

diff --git a/actionview/test/template/render_test.rb b/actionview/test/template/render_test.rb
index 3f298d81f3..e6e80bc1b8 100644
--- a/actionview/test/template/render_test.rb
+++ b/actionview/test/template/render_test.rb
@@ -752,6 +752,17 @@ class CachedCollectionViewRenderTest < ActiveSupport::TestCase
       @view.render(partial: "test/cached_customer", collection: [customer], cached: true)
   end
 
+  test "collection caching does not work on multi-partials" do
+    a = Object.new
+    b = Object.new
+    def a.to_partial_path; "test/partial_iteration_1"; end
+    def b.to_partial_path; "test/partial_iteration_2"; end
+
+    assert_raises(NotImplementedError) do
+      @controller_view.render(partial: [a, b], cached: true)
+    end
+  end
+
   private
     def cache_key(*names, virtual_path)
       digest = ActionView::Digestor.digest name: virtual_path, finder: @view.lookup_context, dependencies: []