From 9e57a608985409788a6dabe5a8a11585f8524bd0 Mon Sep 17 00:00:00 2001
From: Dhrupo <dhrupo@gmail.com>
Date: Tue, 10 Nov 2026 22:54:32 +0600
Subject: [PATCH] REST API: Skip rendering `title` and `content` when the
 schema omits their `rendered` properties.

WP_REST_Blocks_Controller removes `title.rendered` and `content.rendered` from the synced pattern schema, because a block only renders in the context of a post or a page. WP_REST_Posts_Controller::prepare_item_for_response() rendered both anyway, running `the_title` and `the_content` on every pattern REST response, only for filter_response_by_context() to discard the results. With hooks on `the_content`, that is wasted work on a hot editor path.

Only run the rendering passes when the schema actually contains the `rendered` property, so schemas that keep the property are unaffected.

Fixes #66644.
---
 .../class-wp-rest-posts-controller.php        | 13 ++++-
 .../tests/rest-api/rest-blocks-controller.php | 49 +++++++++++++++++++
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
index 0c24925ff9245..3dded105df7bf 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
@@ -1896,6 +1896,15 @@ public function prepare_item_for_response( $item, $request ) {
 		}
 
 		$fields = $this->get_fields_for_response( $request );
+		$schema = $this->get_item_schema();
+
+		/*
+		 * Some controllers, such as the synced patterns controller, remove the
+		 * `rendered` properties from the schema, since a block only renders in the
+		 * context of a post or page. Skip the rendering passes for those fields.
+		 */
+		$can_render_title   = isset( $schema['properties']['title']['properties']['rendered'] );
+		$can_render_content = isset( $schema['properties']['content']['properties']['rendered'] );
 
 		// Base fields for every post.
 		$data = array();
@@ -1975,7 +1984,7 @@ public function prepare_item_for_response( $item, $request ) {
 		if ( rest_is_field_included( 'title.raw', $fields ) ) {
 			$data['title']['raw'] = $post->post_title;
 		}
-		if ( rest_is_field_included( 'title.rendered', $fields ) ) {
+		if ( $can_render_title && rest_is_field_included( 'title.rendered', $fields ) ) {
 			add_filter( 'protected_title_format', array( $this, 'protected_title_format' ) );
 			add_filter( 'private_title_format', array( $this, 'protected_title_format' ) );
 
@@ -2001,7 +2010,7 @@ public function prepare_item_for_response( $item, $request ) {
 		if ( rest_is_field_included( 'content.raw', $fields ) ) {
 			$data['content']['raw'] = $post->post_content;
 		}
-		if ( rest_is_field_included( 'content.rendered', $fields ) ) {
+		if ( $can_render_content && rest_is_field_included( 'content.rendered', $fields ) ) {
 			/** This filter is documented in wp-includes/post-template.php */
 			$data['content']['rendered'] = post_password_required( $post ) ? '' : apply_filters( 'the_content', $post->post_content );
 		}
diff --git a/tests/phpunit/tests/rest-api/rest-blocks-controller.php b/tests/phpunit/tests/rest-api/rest-blocks-controller.php
index 30b8b0d88c68e..ba10c4c65fe84 100644
--- a/tests/phpunit/tests/rest-api/rest-blocks-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-blocks-controller.php
@@ -221,6 +221,55 @@ public function test_content() {
 		);
 	}
 
+	/**
+	 * Check that the rendering callbacks for the stripped `rendered` fields do not run.
+	 *
+	 * `title.rendered` and `content.rendered` are removed from the pattern schema
+	 * and response, so the `the_title` and `the_content` passes should not run at all.
+	 *
+	 * @ticket 66644
+	 */
+	public function test_rendered_fields_are_not_rendered() {
+		wp_set_current_user( self::$user_ids['author'] );
+
+		$post_id = wp_insert_post(
+			array(
+				'post_type'    => 'wp_block',
+				'post_status'  => 'publish',
+				'post_title'   => 'Pattern with excerpt',
+				'post_content' => '<!-- wp:paragraph --><p>Hello!</p><!-- /wp:paragraph -->',
+				'post_excerpt' => 'Pattern excerpt',
+			)
+		);
+
+		$the_content_calls = 0;
+		$the_title_calls   = 0;
+
+		$count_the_content = static function ( $content ) use ( &$the_content_calls ) {
+			$the_content_calls++;
+			return $content;
+		};
+		$count_the_title = static function ( $title ) use ( &$the_title_calls ) {
+			$the_title_calls++;
+			return $title;
+		};
+
+		add_filter( 'the_content', $count_the_content );
+		add_filter( 'the_title', $count_the_title );
+
+		$request  = new WP_REST_Request( 'GET', '/wp/v2/blocks/' . $post_id );
+		$response = rest_get_server()->dispatch( $request );
+
+		remove_filter( 'the_content', $count_the_content );
+		remove_filter( 'the_title', $count_the_title );
+
+		wp_delete_post( $post_id );
+
+		$this->assertSame( 200, $response->get_status() );
+		$this->assertSame( 0, $the_content_calls );
+		$this->assertSame( 0, $the_title_calls );
+	}
+
 	/**
 	 * Check that the `wp_pattern_sync_status` postmeta is moved from meta array to top
 	 * level of response.