WP Rocket's cache is cleared after every update

[vmanthos]

Before submitting an issue please check that you’ve completed the following steps:

• Made sure you’re on the latest version ✔️ 3.13.3
• Used the search feature to ensure that the bug hasn’t been reported before ✔️

Describe the bug

When updating WP Rocket the cache is cleared every time although this may not be the intended behavior.
For example, we have code to clear the cache when updating from a version lower than 3.6:

wp-rocket/inc/admin/upgrader.php

Lines 272 to 275 in 3b6300e

	if ( version_compare( $actual_version, '3.6', '<' ) ) {
	rocket_clean_cache_busting();
	rocket_clean_domain();
	}

This is happening because version isn't part of the $removed array:

wp-rocket/inc/admin/options.php

Lines 25 to 54 in 3b6300e

	$removed = [
	'cache_mobile' => true,
	'purge_cron_interval' => true,
	'purge_cron_unit' => true,
	'database_revisions' => true,
	'database_auto_drafts' => true,
	'database_trashed_posts' => true,
	'database_spam_comments' => true,
	'database_trashed_comments' => true,
	'database_all_transients' => true,
	'database_optimize_tables' => true,
	'schedule_automatic_cleanup' => true,
	'automatic_cleanup_frequency' => true,
	'do_cloudflare' => true,
	'cloudflare_email' => true,
	'cloudflare_api_key' => true,
	'cloudflare_zone_id' => true,
	'cloudflare_devmode' => true,
	'cloudflare_auto_settings' => true,
	'cloudflare_old_settings' => true,
	'heartbeat_admin_behavior' => true,
	'heartbeat_editor_behavior' => true,
	'varnish_auto_purge' => true,
	'analytics_enabled' => true,
	'sucury_waf_cache_sync' => true,
	'sucury_waf_api_key' => true,
	'manual_preload' => true,
	'preload_excluded_uri' => true,
	'cache_reject_uri' => true,
	];

so the following conditional always evaluates to true and rocket_clean_domain() runs clearing the cache:

wp-rocket/inc/admin/options.php

Line 91 in 3b6300e

if ( md5( wp_json_encode( $oldvalue_diff ) ) !== md5( wp_json_encode( $value_diff ) ) ) {

To Reproduce

Steps to reproduce the behavior:

1. Install WP Rocket 3.13.
2. After the cache is preloaded disable Preload.
3. Check the /cache/wp-rocket/ folder.
4. Update to the latest WP Rocket version (3.13.3 at the time this is written).
5. Repeat step 3. The cache will have been cleared.

Expected behavior

This issue should be seen as an opportunity to discuss whether we'll keep the current behavior, i.e. clear the cache after every update, or if we want to do that selectively, e.g. with specific versions.

Screenshots

N/A.

Additional context

N/A.

Backlog Grooming (for WP Media dev team use only)

• Reproduce the problem
• Identify the root cause
• Scope a solution
• Estimate the effort

[piotrbak]

Acceptance Criteria:

1. WP Rocket cache should be cleared during the update when this is specified in the wp-rocket/inc/admin/upgrader.php
2. WP Rocket cache should not be cleared during the update when not asked to

[Tabrisrp]

Reproduce the issue ✅

Reproduced the issue

Identify the root cause ✅

As noted by Vasilis, the version index of the array changes on update, and it's not part of the array of values to ignore, so the clean is triggered on every update

Scope a solution ✅

• Add version to the $removed array in rocket_after_save_options()
• Add an additional test fixture to confirm this change

Estimate the effort ✅

Effort XS