From e07e95e232c7598d59b1897498b608b0d2c31736 Mon Sep 17 00:00:00 2001
From: Pascal Birchler <pascal.birchler@gmail.com>
Date: Tue, 29 Aug 2023 15:35:21 +0000
Subject: [PATCH] Media: Prevent warning if `[caption]` shortcode is used
 without attributes.

Props maltfield, aslamdoctor.
Fixes #59206.
Built from https://develop.svn.wordpress.org/trunk@56488


git-svn-id: http://core.svn.wordpress.org/trunk@56000 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/media.php   | 4 ++++
 wp-includes/version.php | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/wp-includes/media.php b/wp-includes/media.php
index e037a0608b..d365e0b1e1 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -2361,6 +2361,10 @@ add_shortcode( 'caption', 'img_caption_shortcode' );
  * @return string HTML content to display the caption.
  */
 function img_caption_shortcode( $attr, $content = '' ) {
+	if ( ! $attr ) {
+		$attr = array();
+	}
+
 	// New-style shortcode with the caption inside the shortcode with the link and image tags.
 	if ( ! isset( $attr['caption'] ) ) {
 		if ( preg_match( '#((?:<a [^>]+>\s*)?<img [^>]+>(?:\s*</a>)?)(.*)#is', $content, $matches ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 40711286e7..2307a489e9 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-alpha-56484';
+$wp_version = '6.4-alpha-56488';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.