Editor: Backport block supports filter callback, registrations and tests to 6.1.

This changeset backports the following changes:

- Implement [https://github.com/WordPress/gutenberg/pull/42880 gutenberg#42880]: Backport script loader: enqueue stored block supports styles
- Allow a way to bypass `SCRIPT_DEBUG` in tests. See [https://github.com/WordPress/wordpress-develop/pull/3259#issuecomment-1250403735 comment] and the related [https://github.com/WordPress/gutenberg/pull/44248 Gutenberg pull request]

Props ramonopoly, gziolo, bernhard-reiter, audrasjb, costdev.
See #56467.

Built from https://develop.svn.wordpress.org/trunk@54214


git-svn-id: http://core.svn.wordpress.org/trunk@53773 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/default-filters.php

@@ -575,6 +575,10 @@ add_action( 'admin_head', 'wp_check_widget_editor_deps' );
 add_action( 'wp_enqueue_scripts', 'wp_enqueue_global_styles' );
 add_action( 'wp_footer', 'wp_enqueue_global_styles', 1 );
 
+// Block supports, and other styles parsed and stored in the Style Engine.
+add_action( 'wp_enqueue_scripts', 'wp_enqueue_stored_styles' );
+add_action( 'wp_footer', 'wp_enqueue_stored_styles', 1 );
+
 // SVG filters like duotone have to be loaded at the beginning of the body in both admin and the front-end.
 add_action( 'wp_body_open', 'wp_global_styles_render_svg_filters' );
 add_action( 'in_admin_header', 'wp_global_styles_render_svg_filters' );

wp-includes/script-loader.php

@@ -2966,6 +2966,75 @@ function wp_enqueue_block_support_styles( $style, $priority = 10 ) {
 	);
 }
 
+/**
+ * Fetches, processes and compiles stored core styles, then combines and renders them to the page.
+ * Styles are stored via the style engine API.
+ *
+ * @link https://developer.wordpress.org/block-editor/reference-guides/packages/packages-style-engine/
+ *
+ * @since 6.1.0
+ *
+ * @param array $options {
+ *     Optional. An array of options to pass to wp_style_engine_get_stylesheet_from_context(). Default empty array.
+ *
+ *     @type bool $optimize Whether to optimize the CSS output, e.g., combine rules. Default is `false`.
+ *     @type bool $prettify Whether to add new lines and indents to output. Default is the test of whether the global constant `SCRIPT_DEBUG` is defined.
+ * }
+ *
+ * @return void
+ */
+function wp_enqueue_stored_styles( $options = array() ) {
+	$is_block_theme   = wp_is_block_theme();
+	$is_classic_theme = ! $is_block_theme;
+
+	/*
+	 * For block themes, this function prints stored styles in the header.
+	 * For classic themes, in the footer.
+	 */
+	if (
+		( $is_block_theme && doing_action( 'wp_footer' ) ) ||
+		( $is_classic_theme && doing_action( 'wp_enqueue_scripts' ) )
+	) {
+		return;
+	}
+
+	$core_styles_keys         = array( 'block-supports' );
+	$compiled_core_stylesheet = '';
+	$style_tag_id             = 'core';
+	// Adds comment if code is prettified to identify core styles sections in debugging.
+	$should_prettify          = isset( $options['prettify'] ) ? true === $options['prettify'] : defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG;
+	foreach ( $core_styles_keys as $style_key ) {
+		if ( $should_prettify ) {
+			$compiled_core_stylesheet .= "/**\n * Core styles: $style_key\n */\n";
+		}
+		// Chains core store ids to signify what the styles contain.
+		$style_tag_id             .= '-' . $style_key;
+		$compiled_core_stylesheet .= wp_style_engine_get_stylesheet_from_context( $style_key, $options );
+	}
+
+	// Combines Core styles.
+	if ( ! empty( $compiled_core_stylesheet ) ) {
+		wp_register_style( $style_tag_id, false, array(), true, true );
+		wp_add_inline_style( $style_tag_id, $compiled_core_stylesheet );
+		wp_enqueue_style( $style_tag_id );
+	}
+
+	// Prints out any other stores registered by themes or otherwise.
+	$additional_stores = WP_Style_Engine_CSS_Rules_Store::get_stores();
+	foreach ( array_keys( $additional_stores ) as $store_name ) {
+		if ( in_array( $store_name, $core_styles_keys, true ) ) {
+			continue;
+		}
+		$styles = wp_style_engine_get_stylesheet_from_context( $store_name, $options );
+		if ( ! empty( $styles ) ) {
+			$key = "wp-style-engine-$store_name";
+			wp_register_style( $key, false, array(), true, true );
+			wp_add_inline_style( $key, $styles );
+			wp_enqueue_style( $key );
+		}
+	}
+}
+
 /**
  * Enqueues a stylesheet for a specific block.
  *

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-54213';
+$wp_version = '6.1-alpha-54214';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.