From 655c21bbeaa72b4a05fcb1aef95803aecc1464d0 Mon Sep 17 00:00:00 2001
From: Andrew Ozz <admin@laptoptips.ca>
Date: Wed, 24 Apr 2019 21:39:53 +0000
Subject: [PATCH] Fix parsing of inner blocks when auto-generating an excerpt.
 Helps to prevent cases where dynamic inner blocks may cause an infinite loop
 if trying to auto-generate an excerpt.

Props desrosj, pento, gziolo, azaozz.
Fixes #46133.
Built from https://develop.svn.wordpress.org/trunk@45265


git-svn-id: http://core.svn.wordpress.org/trunk@45074 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/blocks.php  | 51 ++++++++++++++++++++++++++++++++++++++---
 wp-includes/version.php |  2 +-
 2 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/wp-includes/blocks.php b/wp-includes/blocks.php
index ba9fc4f344..169e4b3c25 100644
--- a/wp-includes/blocks.php
+++ b/wp-includes/blocks.php
@@ -125,10 +125,9 @@ function get_dynamic_block_names() {
  * @return string The parsed and filtered content.
  */
 function excerpt_remove_blocks( $content ) {
-	$allowed_blocks = array(
+	$allowed_inner_blocks = array(
 		// Classic blocks have their blockName set to null.
 		null,
-		'core/columns',
 		'core/freeform',
 		'core/heading',
 		'core/html',
@@ -141,6 +140,9 @@ function excerpt_remove_blocks( $content ) {
 		'core/table',
 		'core/verse',
 	);
+
+	$allowed_blocks = array_merge( $allowed_inner_blocks, array( 'core/columns' ) );
+
 	/**
 	 * Filters the list of blocks that can contribute to the excerpt.
 	 *
@@ -154,12 +156,55 @@ function excerpt_remove_blocks( $content ) {
 	$allowed_blocks = apply_filters( 'excerpt_allowed_blocks', $allowed_blocks );
 	$blocks         = parse_blocks( $content );
 	$output         = '';
+
 	foreach ( $blocks as $block ) {
 		if ( in_array( $block['blockName'], $allowed_blocks, true ) ) {
+			if ( ! empty( $block['innerBlocks'] ) ) {
+				if ( 'core/columns' === $block['blockName'] ) {
+					$output .= _excerpt_render_inner_columns_blocks( $block, $allowed_inner_blocks );
+					continue;
+				}
+
+				// Skip the block if it has disallowed or nested inner blocks.
+				foreach ( $block['innerBlocks'] as $inner_block ) {
+					if (
+						! in_array( $inner_block['blockName'], $allowed_inner_blocks, true ) ||
+						! empty( $inner_block['innerBlocks'] )
+					) {
+						continue 2;
+					}
+				}
+			}
+
 			$output .= render_block( $block );
 		}
 	}
-	 return $output;
+
+	return $output;
+}
+
+/**
+ * Render inner blocks from the `core/columns` block for generating an excerpt.
+ *
+ * @since 5.2.0
+ * @access private
+ *
+ * @param array $columns        The parsed columns block.
+ * @param array $allowed_blocks The list of allowed inner blocks.
+ * @return string The rendered inner blocks.
+ */
+function _excerpt_render_inner_columns_blocks( $columns, $allowed_blocks ) {
+	$output = '';
+
+	foreach ( $columns['innerBlocks'] as $column ) {
+		foreach ( $column['innerBlocks'] as $inner_block ) {
+			if ( in_array( $inner_block['blockName'], $allowed_blocks, true ) && empty( $inner_block['innerBlocks'] ) ) {
+				$output .= render_block( $inner_block );
+			}
+		}
+	}
+
+	return $output;
 }
 
 /**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0ff9e9fde6..683e8e0297 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.2-beta3-45264';
+$wp_version = '5.2-beta3-45265';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.