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, 24 insertions, 0 deletions

diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
index 7754bd8dd9..bd6f2d788d 100644
--- a/actionview/CHANGELOG.md
+++ b/actionview/CHANGELOG.md
@@ -9,6 +9,30 @@
 
     *Steven Harman*
 
+*   Show cache hits and misses when rendering partials.
+
+    Partials using the `cache` helper will show whether a render hit or missed
+    the cache:
+
+    ```
+    Rendered messages/_message.html.erb in 1.2 ms [cache hit]
+    Rendered recordings/threads/_thread.html.erb in 1.5 ms [cache miss]
+    ```
+
+    This removes the need for the old fragment cache logging:
+
+    ```
+    Read fragment views/v1/2914079/v1/2914079/recordings/70182313-20160225015037000000/d0bdf2974e1ef6d31685c3b392ad0b74 (0.6ms)
+    Rendered messages/_message.html.erb in 1.2 ms [cache hit]
+    Write fragment views/v1/2914079/v1/2914079/recordings/70182313-20160225015037000000/3b4e249ac9d168c617e32e84b99218b5 (1.1ms)
+    Rendered recordings/threads/_thread.html.erb in 1.5 ms [cache miss]
+    ```
+
+    Though that full output can be reenabled with
+    `config.action_controller.enable_fragment_cache_logging = true`.
+
+    *Stan Lo*
+
 *   New syntax for tag helpers. Avoid positional parameters and support HTML5 by default.
     Example usage of tag helpers before: