Modify LogSubscriber for single partial's cache message.

Implement naive partial caching mechanism.

Add test for LogSubscriber

Use ActionView::Base#log_payload to store log_subscriber's payload, so we can pass cache result into it.

Fixed tests

Remove useless settings

Check if #log_payload exists before calling it. Because other classes also includes CacheHelper but don't have is attribute

Use @log_payload_for_partial_reder instead of #log_payload to carry ActionView's payload.

Update test's hash syntax

Add configuration to enable/disable fragment caching logging

Remove unless test and add new test to ensure cache info won't effect next rendering's log

Move :enable_fragment_cache_logging config from ActionView to ActionPack

Apply new config to tests

Update actionview's changelog

Update configuration guide

Improve actionview's changelog

Refactor PartialRenderer#render and log tests

Mute subscriber's log instead of disabling instrumentation.

Fix typo, remove useless comment and use new hash syntax

Improve actionpack's log_subscriber test

Fix rebase mistake

Apply new config to all caching intstrument actions

1 files changed, 7 insertions, 1 deletions

diff --git a/actionview/lib/action_view/helpers/cache_helper.rb b/actionview/lib/action_view/helpers/cache_helper.rb
index 6c3092cc46..b598469d01 100644
--- a/actionview/lib/action_view/helpers/cache_helper.rb
+++ b/actionview/lib/action_view/helpers/cache_helper.rb
@@ -226,7 +226,13 @@ module ActionView
 
       # TODO: Create an object that has caching read/write on it
       def fragment_for(name = {}, options = nil, &block) #:nodoc:
-        read_fragment_for(name, options) || write_fragment_for(name, options, &block)
+        if content = read_fragment_for(name, options)
+          @log_payload_for_partial_render[:cache_hit] = true if defined?(@log_payload_for_partial_render)
+          content
+        else
+          @log_payload_for_partial_render[:cache_hit] = false if defined?(@log_payload_for_partial_render)
+          write_fragment_for(name, options, &block)
+        end
       end
 
       def read_fragment_for(name, options) #:nodoc: