Rename wp_should_load_separate_core_block_assets function to wp_shoul…

src/wp-includes/blocks.php

@@ -304,7 +304,7 @@ function register_block_style_handle( $metadata, $field_name, $index = 0 ) {
 
 	$is_core_block = isset( $metadata['file'] ) && str_starts_with( $metadata['file'], $wpinc_path_norm );
 	// Skip registering individual styles for each core block when a bundled version provided.
-	if ( $is_core_block && ! wp_should_load_separate_core_block_assets() ) {
+	if ( $is_core_block && ! wp_should_load_block_assets_on_demand() ) {
 		return false;
 	}
 
@@ -457,7 +457,7 @@ function register_block_type_from_metadata( $file_or_folder, $args = array() ) {
 		if ( ! isset( $metadata['style'] ) ) {
 			$metadata['style'] = "wp-block-$block_name";
 		}
-		if ( current_theme_supports( 'wp-block-styles' ) && wp_should_load_separate_core_block_assets() ) {
+		if ( current_theme_supports( 'wp-block-styles' ) && wp_should_load_block_assets_on_demand() ) {
 			$metadata['style']   = (array) $metadata['style'];
 			$metadata['style'][] = "wp-block-{$block_name}-theme";
 		}

src/wp-includes/blocks/index.php

@@ -29,7 +29,7 @@
 function register_core_block_style_handles() {
 	$wp_version = wp_get_wp_version();
 
-	if ( ! wp_should_load_separate_core_block_assets() ) {
+	if ( ! wp_should_load_block_assets_on_demand() ) {
 		return;
 	}
 

src/wp-includes/deprecated.php

@@ -6406,3 +6406,46 @@ function wp_create_block_style_variation_instance_name( $block, $variation ) {
 	_deprecated_function( __FUNCTION__, '6.7.0', 'wp_unique_id' );
 	return $variation . '--' . md5( serialize( $block ) );
 }
+
+/**
+ * Checks whether separate styles should be loaded for core blocks on-render.
+ *
+ * When this function returns true, other functions ensure that core blocks
+ * only load their assets on-render, and each block loads its own, individual
+ * assets. Third-party blocks only load their assets when rendered.
+ *
+ * When this function returns false, all core block assets are loaded regardless
+ * of whether they are rendered in a page or not, because they are all part of
+ * the `block-library/style.css` file. Assets for third-party blocks are always
+ * enqueued regardless of whether they are rendered or not.
+ *
+ * This only affects front end and not the block editor screens.
+ *
+ * @see wp_enqueue_registered_block_scripts_and_styles()
+ * @see register_block_style_handle()
+ *
+ * @since 5.8.0
+ * @deprecated 6.8.0 Use {@see 'wp_should_load_block_assets_on_demand'} instead.
+ *
+ * @return bool Whether separate assets will be loaded.
+ */
+function wp_should_load_separate_core_block_assets() {
+	_deprecated_function( __FUNCTION__, '6.8.0', 'wp_should_load_block_assets_on_demand' );
+
+	if ( is_admin() || is_feed() || wp_is_rest_endpoint() ) {
+		return false;
+	}
+
+	/**
+	 * Filters whether block styles should be loaded separately.
+	 *
+	 * Returning false loads all core block assets, regardless of whether they are rendered
+	 * in a page or not. Returning true loads core block assets only when they are rendered.
+	 *
+	 * @since 5.8.0
+	 *
+	 * @param bool $load_separate_assets Whether separate assets will be loaded.
+	 *                                   Default false (all block assets are loaded, even when not used).
+	 */
+	return apply_filters( 'should_load_separate_core_block_assets', false );
+}

src/wp-includes/global-styles-and-settings.php

@@ -260,15 +260,15 @@ function wp_add_global_styles_for_blocks() {
 	foreach ( $block_nodes as $metadata ) {
 		$block_css = $tree->get_styles_for_block( $metadata );
 
-		if ( ! wp_should_load_separate_core_block_assets() ) {
+		if ( ! wp_should_load_block_assets_on_demand() ) {
 			wp_add_inline_style( 'global-styles', $block_css );
 			continue;
 		}
 
 		$stylesheet_handle = 'global-styles';
 
 		/*
-		 * When `wp_should_load_separate_core_block_assets()` is true, block styles are
+		 * When `wp_should_load_block_assets_on_demand()` is true, block styles are
 		 * enqueued for each block on the page in class WP_Block's render function.
 		 * This means there will be a handle in the styles queue for each of those blocks.
 		 * Block-specific global styles should be attached to the global-styles handle, but

src/wp-includes/script-loader.php

@@ -1777,7 +1777,7 @@ function wp_default_styles( $styles ) {
 		$handle = 'wp-' . $package;
 		$path   = "/wp-includes/css/dist/$package/style$suffix.css";
 
-		if ( 'block-library' === $package && wp_should_load_separate_core_block_assets() ) {
+		if ( 'block-library' === $package && wp_should_load_block_assets_on_demand() ) {
 			$path = "/wp-includes/css/dist/$package/common$suffix.css";
 		}
 		$styles->add( $handle, $path, $dependencies );
@@ -2439,7 +2439,7 @@ function wp_common_block_scripts_and_styles() {
 
 	wp_enqueue_style( 'wp-block-library' );
 
-	if ( current_theme_supports( 'wp-block-styles' ) && ! wp_should_load_separate_core_block_assets() ) {
+	if ( current_theme_supports( 'wp-block-styles' ) && ! wp_should_load_block_assets_on_demand() ) {
 		wp_enqueue_style( 'wp-block-library-theme' );
 	}
 
@@ -2486,7 +2486,7 @@ static function ( $node ) {
  * @since 5.8.0
  */
 function wp_enqueue_global_styles() {
-	$separate_assets  = wp_should_load_separate_core_block_assets();
+	$separate_assets  = wp_should_load_block_assets_on_demand();
 	$is_block_theme   = wp_is_block_theme();
 	$is_classic_theme = ! $is_block_theme;
 
@@ -2566,43 +2566,69 @@ function wp_should_load_block_editor_scripts_and_styles() {
 }
 
 /**
- * Checks whether separate styles should be loaded for core blocks on-render.
+ * Determines whether block assets should be loaded on demand.
  *
- * When this function returns true, other functions ensure that core blocks
- * only load their assets on-render, and each block loads its own, individual
- * assets. Third-party blocks only load their assets when rendered.
+ * This function checks if the current request context allows for conditional
+ * loading of block assets. When enabled, only the block assets for blocks
+ * that are actually rendered on the page will be loaded. This approach
+ * improves performance by avoiding the loading of unnecessary stylesheets
+ * and scripts, particularly in cases where blocks are not present in the
+ * content being rendered.
  *
- * When this function returns false, all core block assets are loaded regardless
- * of whether they are rendered in a page or not, because they are all part of
- * the `block-library/style.css` file. Assets for third-party blocks are always
- * enqueued regardless of whether they are rendered or not.
+ * When the function returns true, individual stylesheets for core blocks
+ * will be used instead of loading the full wp-block-library stylesheet.
+ * This behavior is a side effect of the primary purpose of loading block
+ * assets on demand, which also includes third-party blocks.
  *
- * This only affects front end and not the block editor screens.
+ * The function will return false under the following conditions:
+ * - If the current request is in the admin area
+ * - If the current request is for an RSS feed
+ * - If the current request is a REST API endpoint
  *
- * @see wp_enqueue_registered_block_scripts_and_styles()
- * @see register_block_style_handle()
+ * This function is a key component of the block asset management system
+ * introduced in WordPress 5.8. It is recommended to use the associated
+ * filter, 'wp_should_load_block_assets_on_demand', to modify the loading
+ * behavior in custom implementations.
  *
- * @since 5.8.0
+ * Formerly wp_should_load_separate_core_block_assets(), introduced in 5.8.0.
+ *
+ * @since 6.8.0
  *
- * @return bool Whether separate assets will be loaded.
+ * @return bool False if all block assets should be loaded, true if block
+ *               assets should be loaded only when needed (i.e., on demand).
  */
-function wp_should_load_separate_core_block_assets() {
+function wp_should_load_block_assets_on_demand() {
 	if ( is_admin() || is_feed() || wp_is_rest_endpoint() ) {
 		return false;
 	}
 
 	/**
-	 * Filters whether block styles should be loaded separately.
+	 * Backward compatibility for the deprecated `should_load_separate_core_block_assets` filter.
+	 * This filter is documented in wp-includes/deprecated.php
+	 */
+	$should_load = apply_filters_deprecated(
+		'should_load_separate_core_block_assets',
+		array( false ),
+		'6.8.0',
+		'wp_should_load_block_assets_on_demand'
+	);
+
+	/**
+	 * Filters whether block assets should be loaded on demand.
 	 *
-	 * Returning false loads all core block assets, regardless of whether they are rendered
-	 * in a page or not. Returning true loads core block assets only when they are rendered.
+	 * This filter customizes the loading behavior of block styles and scripts.
+	 * When set to true, only the assets for blocks actually rendered on the
+	 * page will be loaded, improving performance by preventing unnecessary
+	 * asset loading. Individual stylesheets for core blocks will be used
+	 * instead of the full wp-block-library stylesheet in this case.
 	 *
-	 * @since 5.8.0
+	 * @since 6.8.0
 	 *
 	 * @param bool $load_separate_assets Whether separate assets will be loaded.
-	 *                                   Default false (all block assets are loaded, even when not used).
+	 *                                    Default false (all block assets are loaded,
+	 *                                    even when not used).
 	 */
-	return apply_filters( 'should_load_separate_core_block_assets', false );
+	return apply_filters( 'wp_should_load_block_assets_on_demand', $should_load );
 }
 
 /**
@@ -2616,7 +2642,7 @@ function wp_should_load_separate_core_block_assets() {
 function wp_enqueue_registered_block_scripts_and_styles() {
 	global $current_screen;
 
-	if ( wp_should_load_separate_core_block_assets() ) {
+	if ( wp_should_load_block_assets_on_demand() ) {
 		return;
 	}
 
@@ -2665,7 +2691,7 @@ function enqueue_block_styles_assets() {
 			if ( isset( $style_properties['style_handle'] ) ) {
 
 				// If the site loads separate styles per-block, enqueue the stylesheet on render.
-				if ( wp_should_load_separate_core_block_assets() ) {
+				if ( wp_should_load_block_assets_on_demand() ) {
 					add_filter(
 						'render_block',
 						static function ( $html, $block ) use ( $block_name, $style_properties ) {
@@ -2687,7 +2713,7 @@ static function ( $html, $block ) use ( $block_name, $style_properties ) {
 				$handle = 'wp-block-library';
 
 				// If the site loads separate styles per-block, check if the block has a stylesheet registered.
-				if ( wp_should_load_separate_core_block_assets() ) {
+				if ( wp_should_load_block_assets_on_demand() ) {
 					$block_stylesheet_handle = generate_block_asset_handle( $block_name, 'style' );
 
 					if ( isset( $wp_styles->registered[ $block_stylesheet_handle ] ) ) {
@@ -3254,7 +3280,7 @@ function wp_enqueue_block_style( $block_name, $args ) {
 	};
 
 	$hook = did_action( 'wp_enqueue_scripts' ) ? 'wp_footer' : 'wp_enqueue_scripts';
-	if ( wp_should_load_separate_core_block_assets() ) {
+	if ( wp_should_load_block_assets_on_demand() ) {
 		/**
 		 * Callback function to register and enqueue styles.
 		 *

src/wp-includes/theme.php

@@ -4394,7 +4394,7 @@ function _add_default_theme_supports() {
 	add_theme_support( 'html5', array( 'comment-form', 'comment-list', 'search-form', 'gallery', 'caption', 'style', 'script' ) );
 	add_theme_support( 'automatic-feed-links' );
 
-	add_filter( 'should_load_separate_core_block_assets', '__return_true' );
+	add_filter( 'wp_should_load_block_assets_on_demand', '__return_true' );
 
 	/*
 	 * Remove the Customizer's Menus panel when block theme is active.

tests/phpunit/tests/blocks/register.php

@@ -571,6 +571,8 @@ public function test_wrong_array_index_do_not_register_block_style_handle() {
 	 * @param string      $block_json_path Path to the `block.json` file, relative to ABSPATH.
 	 * @param string      $style_field     Either 'style' or 'editorStyle'.
 	 * @param string|bool $expected_path   Expected path of registered stylesheet, relative to ABSPATH.
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_register_block_style_handle_uses_correct_core_stylesheet( $block_json_path, $style_field, $expected_path ) {
 		$metadata_file = ABSPATH . $block_json_path;

tests/phpunit/tests/blocks/registerCoreBlockStyleHandles.php

@@ -80,6 +80,8 @@ public function test_wp_should_load_separate_core_block_assets_false( $name, $sc
 	 *
 	 * @param string $name   The block name.
 	 * @param array  $schema The block's schema.
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_wp_should_load_separate_core_block_assets_true( $name, $schema ) {
 		add_filter( 'should_load_separate_core_block_assets', '__return_true' );
@@ -111,6 +113,8 @@ public function test_wp_should_load_separate_core_block_assets_true( $name, $sch
 	 * @dataProvider data_block_data
 	 *
 	 * @param string $name The block name.
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_wp_should_load_separate_core_block_assets_current_theme_supports( $name ) {
 		add_filter( 'should_load_separate_core_block_assets', '__return_true' );
@@ -138,6 +142,8 @@ public function test_wp_should_load_separate_core_block_assets_current_theme_sup
 	 * @dataProvider data_block_data
 	 *
 	 * @param string $name The block name.
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_register_core_block_style_handles_should_load_rtl_stylesheets_for_rtl_text_direction( $name ) {
 		global $wp_locale;

tests/phpunit/tests/dependencies/styles.php

@@ -490,6 +490,8 @@ public function test_block_styles_for_viewing_with_theme_support() {
 	 * @ticket 50263
 	 *
 	 * @covers ::wp_default_styles
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_block_styles_for_viewing_without_split_styles() {
 		add_filter( 'should_load_separate_core_block_assets', '__return_false' );
@@ -507,6 +509,8 @@ public function test_block_styles_for_viewing_without_split_styles() {
 	 * @ticket 50263
 	 *
 	 * @covers ::wp_default_styles
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_block_styles_for_viewing_with_split_styles() {
 		add_filter( 'should_load_separate_core_block_assets', '__return_true' );

tests/phpunit/tests/theme.php

@@ -864,6 +864,9 @@ public function data_block_theme_has_default_support() {
 	 *
 	 * @covers ::_add_default_theme_supports
 	 * @covers ::wp_should_load_separate_core_block_assets
+	 *
+	 * @expectedDeprecated wp_should_load_separate_core_block_assets
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_block_theme_should_load_separate_core_block_assets_by_default() {
 		$this->helper_requires_block_theme();

tests/phpunit/tests/theme/wpAddGlobalStylesForBlocks.php

@@ -78,6 +78,8 @@ public function test_third_party_blocks_inline_styles_get_registered_to_global_s
 	/**
 	 * @ticket 56915
 	 * @ticket 61165
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_third_party_blocks_inline_styles_get_registered_to_global_styles_when_per_block() {
 		$this->set_up_third_party_block();
@@ -103,6 +105,8 @@ public function test_third_party_blocks_inline_styles_get_registered_to_global_s
 	/**
 	 * @ticket 56915
 	 * @ticket 61165
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_third_party_blocks_inline_styles_get_rendered_when_per_block() {
 		$this->set_up_third_party_block();
@@ -153,6 +157,8 @@ public function test_blocks_inline_styles_get_rendered() {
 	/**
 	 * @ticket 57868
 	 * @ticket 61165
+	 *
+	 * @expectedDeprecated should_load_separate_core_block_assets
 	 */
 	public function test_third_party_blocks_inline_styles_for_elements_get_rendered_when_per_block() {
 		$this->set_up_third_party_block();