From eef2e5c85c2e5e1cd7cce1671bce1b2e312afe9d Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov.ru@gmail.com>
Date: Wed, 16 Sep 2020 02:29:06 +0000
Subject: [PATCH] Code Modernization: Return an empty string from
 `wpdb::prepare()` if there are not enough arguments to match the
 placeholders.

This avoids a fatal error on PHP 8 caused by passing mismatched arguments to `vsprintf()`, and maintains the current behaviour.

Follow-up to [48979], [48980].

See #50913, #50639.
Built from https://develop.svn.wordpress.org/trunk@48981


git-svn-id: http://core.svn.wordpress.org/trunk@48743 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/version.php |  2 +-
 wp-includes/wp-db.php   | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/wp-includes/version.php b/wp-includes/version.php
index 7289f20059..9cc4371360 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-48980';
+$wp_version = '5.6-alpha-48981';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
diff --git a/wp-includes/wp-db.php b/wp-includes/wp-db.php
index 9761de99a8..ebcadb6ef0 100644
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -1369,7 +1369,9 @@ class wpdb {
 		// Count the number of valid placeholders in the query.
 		$placeholders = preg_match_all( "/(^|[^%]|(%%)+)%($allowed_format)?[sdF]/", $query, $matches );
 
-		if ( count( $args ) !== $placeholders ) {
+		$args_count = count( $args );
+
+		if ( $args_count !== $placeholders ) {
 			if ( 1 === $placeholders && $passed_as_array ) {
 				// If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
 				wp_load_translations_early();
@@ -1392,10 +1394,22 @@ class wpdb {
 						/* translators: 1: Number of placeholders, 2: Number of arguments passed. */
 						__( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
 						$placeholders,
-						count( $args )
+						$args_count
 					),
 					'4.8.3'
 				);
+
+				/*
+				 * If we don't have enough arguments to match the placeholders,
+				 * return an empty string to avoid a fatal error on PHP 8.
+				 */
+				if ( $args_count < $placeholders ) {
+					$max_numbered_placeholder = ! empty( $matches[3] ) ? max( array_map( 'intval', $matches[3] ) ) : 0;
+
+					if ( ! $max_numbered_placeholder || $args_count < $max_numbered_placeholder ) {
+						return '';
+					}
+				}
 			}
 		}