From 54d732ae5b15e973f1ca0299ed10c1fa1d026039 Mon Sep 17 00:00:00 2001
From: Peter Petrov <peter.petrov89@gmail.com>
Date: Fri, 17 Jan 2025 10:39:47 +0200
Subject: [PATCH] Boost: Reduce unnecessary CSS regenerations (#40891)

---
 .../providers/Singular_Post_Provider.php      |  4 +--
 .../providers/Taxonomy_Provider.php           |  4 +--
 .../optimizations/cloud-css/Cloud_CSS.php     | 28 ++++++++++++++++++-
 ...e-boost-reduce-unnecessary-css-generations |  4 +++
 4 files changed, 35 insertions(+), 5 deletions(-)
 create mode 100644 projects/plugins/boost/changelog/update-boost-reduce-unnecessary-css-generations

diff --git a/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Singular_Post_Provider.php b/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Singular_Post_Provider.php
index f258e15095c2d..ffebe55be2f3e 100644
--- a/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Singular_Post_Provider.php
+++ b/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Singular_Post_Provider.php
@@ -26,14 +26,14 @@ class Singular_Post_Provider extends Provider {
 	 *
 	 * @var integer
 	 */
-	const MAX_URLS = 20;
+	const MAX_URLS = 10;
 
 	/**
 	 * Minimum number of posts to have Critical CSS generated in order for the whole process to be successful.
 	 *
 	 * @var integer
 	 */
-	const MIN_SUCCESS_URLS = 10;
+	const MIN_SUCCESS_URLS = 5;
 
 	// phpcs:ignore Generic.Commenting.DocComment.MissingShort
 	/** @inheritdoc */
diff --git a/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Taxonomy_Provider.php b/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Taxonomy_Provider.php
index 3aea6dc713e60..b628be3521e03 100644
--- a/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Taxonomy_Provider.php
+++ b/projects/plugins/boost/app/lib/critical-css/source-providers/providers/Taxonomy_Provider.php
@@ -26,14 +26,14 @@ class Taxonomy_Provider extends Provider {
 	 *
 	 * @var integer
 	 */
-	const MAX_URLS = 20;
+	const MAX_URLS = 10;
 
 	/**
 	 * Minimum number of posts to have Critical CSS generated in order for the whole process to be successful.
 	 *
 	 * @var integer
 	 */
-	const MIN_SUCCESS_URLS = 10;
+	const MIN_SUCCESS_URLS = 5;
 
 	// phpcs:ignore Generic.Commenting.DocComment.MissingShort
 	/** @inheritdoc */
diff --git a/projects/plugins/boost/app/modules/optimizations/cloud-css/Cloud_CSS.php b/projects/plugins/boost/app/modules/optimizations/cloud-css/Cloud_CSS.php
index 9a06999349920..c522d344c763d 100644
--- a/projects/plugins/boost/app/modules/optimizations/cloud-css/Cloud_CSS.php
+++ b/projects/plugins/boost/app/modules/optimizations/cloud-css/Cloud_CSS.php
@@ -159,7 +159,13 @@ public function handle_save_post( $post_id, $post ) { // phpcs:ignore VariableAn
 			return;
 		}
 
-		$this->regenerate_cloud_css( self::REGENERATE_REASON_SAVE_POST, $this->get_all_providers( array( $post ) ) );
+		// This checks against the latest providers list, not the list
+		// stored in the database because newly added posts are always
+		// included in the providers list that will be used to generate
+		// the Cloud CSS.
+		if ( $this->is_post_in_latest_providers_list( $post ) ) {
+			$this->regenerate_cloud_css( self::REGENERATE_REASON_SAVE_POST, $this->get_all_providers( array( $post ) ) );
+		}
 	}
 
 	public function regenerate_cloud_css( $reason, $providers ) {
@@ -171,6 +177,26 @@ public function regenerate_cloud_css( $reason, $providers ) {
 		return $result;
 	}
 
+	/**
+	 * Check if the post is in the latest providers list.
+	 *
+	 * @param int|\WP_Post $post The post to check.
+	 *
+	 * @return bool
+	 */
+	public function is_post_in_latest_providers_list( $post ) {
+		$post_link = get_permalink( $post );
+		$providers = $this->get_all_providers();
+
+		foreach ( $providers as $provider ) {
+			if ( in_array( $post_link, $provider['urls'], true ) ) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 	/**
 	 * Called when stored Critical CSS has been invalidated. Triggers a new Cloud CSS request.
 	 */
diff --git a/projects/plugins/boost/changelog/update-boost-reduce-unnecessary-css-generations b/projects/plugins/boost/changelog/update-boost-reduce-unnecessary-css-generations
new file mode 100644
index 0000000000000..a46d7a6f8dd62
--- /dev/null
+++ b/projects/plugins/boost/changelog/update-boost-reduce-unnecessary-css-generations
@@ -0,0 +1,4 @@
+Significance: patch
+Type: changed
+
+Critical CSS: Reduce unnecessary regenerations.