Boost: Invalidate LCP Data on Environment Changes

[LiamSarsfield]

Resolves HOG-84:Invalidate LCP when theme is switched

Proposed changes:

• Introduces a new LCP_Invalidator class to handle the invalidation (clearing) of stored LCP (Largest Contentful Paint) analysis data.
• LCP data is now reset when:
  • A "major" environment change occurs (currently, this is triggered by after_switch_theme).
  • The Jetpack Boost plugin is deactivated (jetpack_boost_deactivate action).
• Adds a new action jetpack_boost_lcp_invalidated which fires after LCP data has been cleared by the invalidator.
• Updates the Lcp class to hook into jetpack_boost_lcp_invalidated to restart the LCP analysis process after invalidation.
• Deprecates the jetpack_boost_critical_css_environment_changed action in favor of the more general jetpack_boost_environment_changed. The old action will still work but trigger a deprecated notice.
• Updates the Cloud_CSS class to use the new jetpack_boost_environment_changed action.
• Also removed cornerstone-specific env change handling in Cloud_CSS

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

pc9hqz-3tr-p2

Does this pull request change what data or activity we track or use?

N/A

Testing instructions:

Prerequisites:

• Jetpack Boost plugin installed and activated.

• LCP Optimization feature enabled.

  Click here for SQL to check LCP State Option and Storage Posts

  -- Check LCP State (in options table)
  SELECT option_name, option_value
  FROM wp_options -- Replace wp_ with your table prefix if different
  WHERE option_name = 'jetpack_boost_ds_lcp_state';
  
  -- Check LCP Storage (in posts table)
  SELECT ID, post_name, post_content, post_status, post_date_gmt, post_modified_gmt
  FROM wp_posts -- Replace wp_ with your table prefix if different
  WHERE post_type = 'jb_store_lcp';

Testing Theme Switch (Major Change):

1. Note the current LCP state option value and any existing LCP storage posts. Pay attention to the data, and note the post_modified_gmt timestamps of the existing posts.

   Click here for SQL to check initial LCP State and Storage

   -- Check LCP State (in options table)
   SELECT option_name, option_value
   FROM wp_options -- Replace wp_ with your table prefix if different
   WHERE option_name = 'jetpack_boost_ds_lcp_state';
   
   -- Check LCP Storage (in posts table)
   SELECT ID, post_name, post_content, post_status, post_date_gmt, post_modified_gmt
   FROM wp_posts -- Replace wp_ with your table prefix if different
   WHERE post_type = 'jb_store_lcp';

2. Go to Appearance -> Themes.

3. Activate a different theme. Note the approximate time of activation.

4. Wait a few seconds for the analysis to complete (it should be quick).

5. Re-check the jetpack_boost_ds_lcp_state option in the wp_options table. Verify its value has been updated (it won't have a timestamp, but the content should reflect recent analysis).

6. Re-check the wp_posts table for jb_store_lcp posts. Verify that new posts now exist and their post_date_gmt or post_modified_gmt timestamps are after the time you activated the theme.

   Click here for SQL to check updated LCP State and new Storage posts

   -- Check LCP State (in options table)
   SELECT option_name, option_value
   FROM wp_options -- Replace wp_ with your table prefix if different
   WHERE option_name = 'jetpack_boost_ds_lcp_state';
   -- Expect option_value to contain data reflecting the new analysis state
   
   -- Check LCP Storage (in posts table)
   SELECT ID, post_name, post_content, post_status, post_date_gmt, post_modified_gmt
   FROM wp_posts -- Replace wp_ with your table prefix if different
   WHERE post_type = 'jb_store_lcp' AND post_status != 'trash';
   -- Expect new posts corresponding to visited pages with recent timestamps

Testing Plugin Deactivation:

1. Ensure there is some LCP data stored (check state option and storage posts).

   Click here for SQL to check initial LCP State and Storage

   -- Check LCP State (in options table)
   SELECT option_name, option_value
   FROM wp_options -- Replace wp_ with your table prefix if different
   WHERE option_name = 'jetpack_boost_ds_lcp_state';
   
   -- Check LCP Storage (in posts table)
   SELECT ID, post_name, post_content, post_status, post_date_gmt, post_modified_gmt
   FROM wp_posts -- Replace wp_ with your table prefix if different
   WHERE post_type = 'jb_store_lcp';

2. Go to Plugins -> Installed Plugins.

3. Deactivate the Jetpack Boost plugin.

4. Verify that the jetpack_boost_ds_lcp_state option has been cleared or reset, and that all jb_store_lcp posts have been deleted/trashed.

   Click here for SQL to verify LCP State is cleared and Storage posts are deleted

   -- Check LCP State (in options table)
   SELECT option_name, option_value
   FROM wp_options -- Replace wp_ with your table prefix if different
   WHERE option_name = 'jetpack_boost_ds_lcp_state';
   -- Expect option_value to be empty or reflect a default/cleared state
   
   -- Check LCP Storage (in posts table)
   SELECT COUNT(*) as post_count
   FROM wp_posts -- Replace wp_ with your table prefix if different
   WHERE post_type = 'jb_store_lcp' AND post_status != 'trash';
   -- Expect post_count to be 0

Testing Deprecated Action:

1. Add the following PHP snippet to your site (e.g., in a custom plugin or your theme's functions.php).

   Click here for PHP Snippet to test deprecated action

   <?php
   /**
    * Plugin Name: Test Boost Deprecated Action
    * Description: Logs when the deprecated jetpack_boost_critical_css_environment_changed action fires.
    */
   
   add_action( 'jetpack_boost_critical_css_environment_changed', 'my_test_boost_deprecated_action_listener', 10, 2 );
   
   function my_test_boost_deprecated_action_listener( $is_major_change, $change_type ) {
       // Log a message to the PHP error log when the deprecated action runs
       error_log( 
           sprintf( 
               'Deprecated action jetpack_boost_critical_css_environment_changed fired. Is major: %s, Type: %s', 
               var_export( $is_major_change, true ), // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_var_export
               esc_html( $change_type ) 
           ) 
       );
   }

2. Ensure WP_DEBUG and WP_DEBUG_LOG are enabled in your wp-config.php file so that deprecation notices and the custom log message are written to /wp-content/debug.log.

3. Trigger an environment change (e.g., switch themes via Appearance -> Themes, or save a published post/page).

4. Check your /wp-content/debug.log file. Verify that:

   • The custom log message "Deprecated action jetpack_boost_critical_css_environment_changed fired..." appears.
   • A PHP Deprecated notice appears for jetpack_boost_critical_css_environment_changed, indicating it was called and suggesting jetpack_boost_environment_changed instead.

Testing Cloud_CSS Update:

1. Ensure Cloud CSS is active and configured.
2. Trigger environment changes (switching themes, saving posts/pages).
3. Verify that Cloud CSS generation/invalidation still behaves correctly (e.g., CSS is regenerated/invalidated appropriately based on the change type and is_major_change flag passed to jetpack_boost_environment_changed).

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[jp-launch-control]

Code Coverage Summary

Coverage changed in 3 files.

File	Coverage	Δ%	Δ Uncovered
projects/plugins/boost/app/lib/class-environment-change-detector.php	0/39 (0.00%)	0.00%	6 💔
projects/plugins/boost/app/modules/optimizations/lcp/class-lcp.php	0/124 (0.00%)	0.00%	3 ❤️‍🩹
projects/plugins/boost/app/modules/optimizations/cloud-css/class-cloud-css.php	1/81 (1.23%)	0.03%	-2 💚

1 file is newly checked for coverage.

File	Coverage
projects/plugins/boost/app/modules/optimizations/lcp/class-lcp-invalidator.php	0/9 (0.00%) 💔

Full summary · PHP report · JS report

_{Coverage check overridden by Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR .}

[dilirity]

I think this is ready for a merge, but considering I wrote the majority of the code, I'd like for someone else to review it as well.

[dilirity]

I noticed this was added in https://github.com/Automattic/jetpack/pull/41516/files but was unused even there.

[LiamSarsfield]

I fixed a merge conflict after merging #43150, but these changes LGTM @dilirity

[donnchawp]

I tested everything but the cloud css test at the end and they all worked. I'll take a look at the cloud css part tomorrow morning.