Fix rendering callout blocks as notice blocks, again (#664)

* Revert "Revert "Fix rendering callout blocks as notice blocks (#662)" (#663)"

This reverts commit b2dea2b.

* Stop running shortcode block content through render_shortcode

* Hide only empty elements which are allowed

Some other empty elements are added via scripts, eg. iframe

mu-plugins/blocks/notice/index.php

@@ -9,6 +9,8 @@
 // Run after `WPorg_Handbook_Callout_Boxes` registers the shortcodes.
 add_action( 'init', __NAMESPACE__ . '\init', 11 );
 
+add_filter( 'pre_render_block', __NAMESPACE__ . '\render_callout_block_as_notice', 11, 2 );
+
 /**
  * Registers the block using the metadata loaded from the `block.json` file.
  * Behind the scenes, it registers also all assets so they can be enqueued
@@ -26,32 +28,31 @@ function init() {
 }
 
 /**
- * Display the callout shortcodes using the notice block.
+ * Maps a callout type to a notice type.
  *
- * @param array|string $attr    Shortcode attributes array or empty string.
- * @param string       $content Shortcode content.
- * @param string       $tag     Shortcode name.
- *
- * @return string Shortcode output as HTML markup.
+ * @param string $type The callout type.
+ * @return string The corresponding notice type.
  */
-function render_shortcode( $attr, $content, $tag ) {
-	$shortcode_mapping = array(
+function map_type( $type ) {
+	$mapping = array(
 		'info'     => 'info',
 		'tip'      => 'tip',
 		'alert'    => 'alert',
 		'tutorial' => 'tip',
 		'warning'  => 'warning',
 	);
 
-	$type = $shortcode_mapping[ $tag ] ?: 'tip';
-
-	// Sanitize message content.
-	$content = wp_kses_post( $content );
-	// Temporarily disable o2 processing while formatting content.
-	add_filter( 'o2_process_the_content', '__return_false', 1 );
-	$content = apply_filters( 'the_content', $content );
-	remove_filter( 'o2_process_the_content', '__return_false', 1 );
+	return $mapping[ $type ] ?: 'tip';
+}
 
+/**
+ * Generates and processes block markup for a notice.
+ *
+ * @param string $type The notice type.
+ * @param string $content The content to insert into the block.
+ * @return string The processed block markup.
+ */
+function generate_notice_block_markup( $type, $content ) {
 	// Create a unique placeholder for the content.
 	// Directly processing `$content` with `do_blocks` can lead to buggy layouts on make.wp.org.
 	// See https://github.com/WordPress/wporg-mu-plugins/pull/337#issuecomment-1819992059.
@@ -66,7 +67,55 @@ function render_shortcode( $attr, $content, $tag ) {
 EOT;
 
 	$processed_markup = do_blocks( $block_markup );
-	$final_markup = str_replace( $placeholder, $content, $processed_markup );
+	return str_replace( $placeholder, $content, $processed_markup );
+}
+
+/**
+ * Display the callout shortcodes using the notice block.
+ *
+ * @param array|string $attr    Shortcode attributes array or empty string.
+ * @param string       $content Shortcode content.
+ * @param string       $tag     Shortcode name.
+ *
+ * @return string Shortcode output as HTML markup.
+ */
+function render_shortcode( $attr, $content, $tag ) {
+	$type = map_type( $tag );
+
+	// Sanitize message content.
+	$content = wp_kses_post( $content );
+	// Temporarily disable o2 processing while formatting content.
+	add_filter( 'o2_process_the_content', '__return_false', 1 );
+	$content = apply_filters( 'the_content', $content );
+	remove_filter( 'o2_process_the_content', '__return_false', 1 );
+
+	return generate_notice_block_markup( $type, $content );
+}
+
+/**
+ * Renders a callout block as a notice block.
+ *
+ * @param string|null $pre_render The pre-rendered content or null.
+ * @param array       $parsed_block The parsed block array.
+ * @return string|null The rendered notice or the original pre-render value.
+ */
+function render_callout_block_as_notice( $pre_render, $parsed_block ) {
+	if ( is_admin() || 'wporg/callout' !== $parsed_block['blockName'] ) {
+		return $pre_render;
+	}
+
+	$callout_wrapper = $parsed_block['innerHTML'];
+	// Extract the specific "callout-*" class and remove the "callout-" prefix
+	preg_match( '/\bcallout-([\w-]+)\b/', $callout_wrapper, $matches );
+	$tag = $matches[1] ?? 'tip';
+	$type = map_type( $tag );
+
+	$content = '';
+	foreach ( $parsed_block['innerBlocks'] as $inner_block ) {
+		$content .= render_block( $inner_block );
+	}
+	// Sanitize message content.
+	$content = wp_kses_post( $content );
 
-	return $final_markup;
+	return generate_notice_block_markup( $type, $content );
 }

mu-plugins/blocks/notice/postcss/style.pcss

@@ -27,18 +27,6 @@
 		align-self: start;
 	}
 
-	& p:first-child {
-		margin-block-start: 0;
-	}
-
-	& p:last-child {
-		margin-block-end: 0;
-	}
-
-	& br:first-child {
-		display: none;
-	}
-
 	&.alignleft,
 	&.alignright {
 		max-width: calc(var(--wp--style--global--content-size, 680px) * 0.66);
@@ -78,4 +66,25 @@
 
 .wp-block-wporg-notice__content {
 	align-self: center;
+
+	& p:empty,
+	& ul:empty,
+	& ol:empty,
+	& br:first-child {
+		display: none;
+	}
+
+	& :first-child,
+	&:has(:first-child:empty) :nth-child(2) {
+		margin-block-start: 0;
+	}
+
+	& :last-child,
+	&:has(:last-child:empty) :nth-last-child(2),
+	/* o2 adds a data script tag to the notice content on some Make blogs.
+	 * In this case we need to remove bottom margin from the second to last element instead.
+	 */
+	&:has(.o2-data) :nth-last-child(2) {
+		margin-block-end: 0;
+	}
 }