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, 17 insertions, 15 deletions

diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb
index 1509726a37..92bd0ccf91 100644
--- a/actionview/lib/action_view/renderer/partial_renderer.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer.rb
@@ -308,9 +308,7 @@ module ActionView
       if @collection
         render_collection
       else
-        instrument(:partial) do
-          render_partial
-        end
+        render_partial
       end
     end
 
@@ -331,22 +329,26 @@ module ActionView
       end
 
       def render_partial
-        view, locals, block = @view, @locals, @block
-        object, as = @object, @variable
+        instrument(:partial) do |payload|
+          view, locals, block = @view, @locals, @block
+          object, as = @object, @variable
 
-        if !block && (layout = @options[:layout])
-          layout = find_template(layout.to_s, @template_keys)
-        end
+          view.instance_variable_set(:@log_payload_for_partial_render, payload)
 
-        object = locals[as] if object.nil? # Respect object when object is false
-        locals[as] = object if @has_object
+          if !block && (layout = @options[:layout])
+            layout = find_template(layout.to_s, @template_keys)
+          end
 
-        content = @template.render(view, locals) do |*name|
-          view._layout_for(*name, &block)
-        end
+          object = locals[as] if object.nil? # Respect object when object is false
+          locals[as] = object if @has_object
 
-        content = layout.render(view, locals){ content } if layout
-        content
+          content = @template.render(view, locals) do |*name|
+            view._layout_for(*name, &block)
+          end
+
+          content = layout.render(view, locals){ content } if layout
+          content
+        end
       end
 
     # Sets up instance variables needed for rendering a partial. This method