From e2a64f0cd289d1613d6939b53a581492bf2b6ee7 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov.ru@gmail.com>
Date: Wed, 11 Aug 2021 13:01:56 +0000
Subject: [PATCH] Themes: Make sure the theme API response is not an error
 before operating on it in `themes_api()`.

This fixes a potential bug and avoids PHP warnings when `themes_api( 'query_themes' )` is called and a successful API response is not received.

Follow-up to [42632].

Props pierlo.
Fixes #53913.
Built from https://develop.svn.wordpress.org/trunk@51601


git-svn-id: http://core.svn.wordpress.org/trunk@51212 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/theme.php | 19 +++++++++++--------
 wp-includes/version.php     |  2 +-
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/wp-admin/includes/theme.php b/wp-admin/includes/theme.php
index 772e66f139..153c319656 100644
--- a/wp-admin/includes/theme.php
+++ b/wp-admin/includes/theme.php
@@ -602,15 +602,18 @@ function themes_api( $action, $args = array() ) {
 			}
 		}
 
-		// Back-compat for info/1.2 API, upgrade the theme objects in query_themes to objects.
-		if ( 'query_themes' === $action ) {
-			foreach ( $res->themes as $i => $theme ) {
-				$res->themes[ $i ] = (object) $theme;
+		if ( ! is_wp_error( $res ) ) {
+			// Back-compat for info/1.2 API, upgrade the theme objects in query_themes to objects.
+			if ( 'query_themes' === $action ) {
+				foreach ( $res->themes as $i => $theme ) {
+					$res->themes[ $i ] = (object) $theme;
+				}
+			}
+
+			// Back-compat for info/1.2 API, downgrade the feature_list result back to an array.
+			if ( 'feature_list' === $action ) {
+				$res = (array) $res;
 			}
-		}
-		// Back-compat for info/1.2 API, downgrade the feature_list result back to an array.
-		if ( 'feature_list' === $action ) {
-			$res = (array) $res;
 		}
 	}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index c1c1d4f2d9..8a7ebec236 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51600';
+$wp_version = '5.9-alpha-51601';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.