diff -r be944660c56a -r 3d72ae0968f4 wp/wp-includes/blocks/comment-template.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/blocks/comment-template.php	Tue Sep 27 16:37:53 2022 +0200
@@ -0,0 +1,123 @@
+<?php
+/**
+ * Server-side rendering of the `core/comment-template` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Function that recursively renders a list of nested comments.
+ *
+ * @global int $comment_depth
+ *
+ * @param WP_Comment[] $comments        The array of comments.
+ * @param WP_Block     $block           Block instance.
+ * @return string
+ */
+function block_core_comment_template_render_comments( $comments, $block ) {
+	global $comment_depth;
+
+	if ( empty( $comment_depth ) ) {
+		$comment_depth = 1;
+	}
+
+	$content = '';
+	foreach ( $comments as $comment ) {
+
+		$block_content = ( new WP_Block(
+			$block->parsed_block,
+			array(
+				'commentId' => $comment->comment_ID,
+			)
+		) )->render( array( 'dynamic' => false ) );
+
+		$children = $comment->get_children();
+
+		/*
+		 * We need to create the CSS classes BEFORE recursing into the children.
+		 * This is because comment_class() uses globals like `$comment_alt`
+		 * and `$comment_thread_alt` which are order-sensitive.
+		 *
+		 * The `false` parameter at the end means that we do NOT want the function
+		 * to `echo` the output but to return a string.
+		 * See https://developer.wordpress.org/reference/functions/comment_class/#parameters.
+		 */
+		$comment_classes = comment_class( '', $comment->comment_ID, $comment->comment_post_ID, false );
+
+		// If the comment has children, recurse to create the HTML for the nested
+		// comments.
+		if ( ! empty( $children ) ) {
+			$comment_depth += 1;
+			$inner_content  = block_core_comment_template_render_comments(
+				$children,
+				$block
+			);
+			$block_content .= sprintf( '<ol>%1$s</ol>', $inner_content );
+			$comment_depth -= 1;
+		}
+
+		$content .= sprintf( '<li id="comment-%1$s" %2$s>%3$s</li>', $comment->comment_ID, $comment_classes, $block_content );
+	}
+
+	return $content;
+
+}
+
+/**
+ * Renders the `core/comment-template` block on the server.
+ *
+ * @param array    $attributes Block attributes.
+ * @param string   $content    Block default content.
+ * @param WP_Block $block      Block instance.
+ *
+ * @return string Returns the HTML representing the comments using the layout
+ * defined by the block's inner blocks.
+ */
+function render_block_core_comment_template( $attributes, $content, $block ) {
+	// Bail out early if the post ID is not set for some reason.
+	if ( empty( $block->context['postId'] ) ) {
+		return '';
+	}
+
+	if ( post_password_required( $block->context['postId'] ) ) {
+		return;
+	}
+
+	$comment_query = new WP_Comment_Query(
+		build_comment_query_vars_from_block( $block )
+	);
+
+	// Get an array of comments for the current post.
+	$comments = $comment_query->get_comments();
+	if ( count( $comments ) === 0 ) {
+		return '';
+	}
+
+	$comment_order = get_option( 'comment_order' );
+
+	if ( 'desc' === $comment_order ) {
+		$comments = array_reverse( $comments );
+	}
+
+	$wrapper_attributes = get_block_wrapper_attributes();
+
+	return sprintf(
+		'<ol %1$s>%2$s</ol>',
+		$wrapper_attributes,
+		block_core_comment_template_render_comments( $comments, $block )
+	);
+}
+
+/**
+ * Registers the `core/comment-template` block on the server.
+ */
+function register_block_core_comment_template() {
+	register_block_type_from_metadata(
+		__DIR__ . '/comment-template',
+		array(
+			'render_callback'   => 'render_block_core_comment_template',
+			'skip_inner_blocks' => true,
+		)
+	);
+}
+add_action( 'init', 'register_block_core_comment_template' );