Adapt [823aa223efbac6ad4d31ea33402892267bb77cb4] to make sure we perform cloning before manipulation only on `OutputBuffer`.

After the fragment rendering, `Builder` returns the `String` object instead of `ActionView::OutputBuffer`. Somehow the same procedure which was in [823aa223efbac6ad4d31ea33402892267bb77cb4] does not play nice with the String, and result in the fragment got lost.

1 files changed, 7 insertions, 3 deletions

diff --git a/actionpack/lib/action_view/helpers/cache_helper.rb b/actionpack/lib/action_view/helpers/cache_helper.rb
index d070f14af1..b57617b3d1 100644
--- a/actionpack/lib/action_view/helpers/cache_helper.rb
+++ b/actionpack/lib/action_view/helpers/cache_helper.rb
@@ -51,9 +51,13 @@ module ActionView
           # This dance is needed because Builder can't use capture
           pos = output_buffer.length
           yield
-          safe_output_buffer = output_buffer.to_str
-          fragment = safe_output_buffer.slice!(pos..-1)
-          self.output_buffer = ActionView::OutputBuffer.new(safe_output_buffer)
+          if output_buffer.is_a?(ActionView::OutputBuffer)
+            safe_output_buffer = output_buffer.to_str
+            fragment = safe_output_buffer.slice!(pos..-1)
+            self.output_buffer = ActionView::OutputBuffer.new(safe_output_buffer)
+          else
+            fragment = output_buffer.slice!(pos..-1)
+          end
           controller.write_fragment(name, fragment, options)
         end
       end