From 945ba795dc69638d9c2ee8ce1d527022c779f66d Mon Sep 17 00:00:00 2001
From: desrosj <desrosj@git.wordpress.org>
Date: Mon, 17 Dec 2018 18:39:52 +0000
Subject: [PATCH] WPDB: Check that `$wpdb->last_result` is countable before
 counting with it.

`wpdb::get_col()` iterates over `$wpdb->last_result`, which can be a non-countable value, should the preceding query have failed.

Props spacedmonkey, desrosj, pento.

Merges [43934] into trunk.

See #45299.
Built from https://develop.svn.wordpress.org/trunk@44272


git-svn-id: http://core.svn.wordpress.org/trunk@44102 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/version.php |  2 +-
 wp-includes/wp-db.php   | 18 +++++++++++-------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/wp-includes/version.php b/wp-includes/version.php
index 94b2044f54..7056244a85 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44271';
+$wp_version = '5.1-alpha-44272';
 
 /**
  * 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 ae08158f64..af42aaf841 100644
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -2544,8 +2544,10 @@ class wpdb {
 
 		$new_array = array();
 		// Extract the column values
-		for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
-			$new_array[ $i ] = $this->get_var( null, $x, $i );
+		if ( $this->last_result ) {
+			for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
+				$new_array[ $i ] = $this->get_var( null, $x, $i );
+			}
 		}
 		return $new_array;
 	}
@@ -2585,11 +2587,13 @@ class wpdb {
 		} elseif ( $output == OBJECT_K ) {
 			// Return an array of row objects with keys from column 1
 			// (Duplicates are discarded)
-			foreach ( $this->last_result as $row ) {
-				$var_by_ref = get_object_vars( $row );
-				$key        = array_shift( $var_by_ref );
-				if ( ! isset( $new_array[ $key ] ) ) {
-					$new_array[ $key ] = $row;
+			if ( $this->last_result ) {
+				foreach ( $this->last_result as $row ) {
+					$var_by_ref = get_object_vars( $row );
+					$key        = array_shift( $var_by_ref );
+					if ( ! isset( $new_array[ $key ] ) ) {
+						$new_array[ $key ] = $row;
+					}
 				}
 			}
 			return $new_array;