From 617097260d0157c815f573c560539fd7efafbb78 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Mon, 23 Nov 2020 13:34:21 +0000
Subject: [PATCH] Plugins: Check if `_error_nonce` is set before attempting to
 verify it.

This avoids a PHP notice on the Plugins screen when `error` query string is added to the URL.

Props wponlinesupport.
Fixes #43876.

git-svn-id: https://develop.svn.wordpress.org/trunk@49683 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/plugins.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/wp-admin/plugins.php b/src/wp-admin/plugins.php
index d8f909a7da..70abe322ed 100644
--- a/src/wp-admin/plugins.php
+++ b/src/wp-admin/plugins.php
@@ -641,7 +641,9 @@ if ( isset( $_GET['error'] ) ) :
 	<div id="message" class="error"><p><?php echo $errmsg; ?></p>
 	<?php
 
-	if ( ! isset( $_GET['main'] ) && ! isset( $_GET['charsout'] ) && wp_verify_nonce( $_GET['_error_nonce'], 'plugin-activation-error_' . $plugin ) ) {
+	if ( ! isset( $_GET['main'] ) && ! isset( $_GET['charsout'] )
+		&& isset( $_GET['_error_nonce'] ) && wp_verify_nonce( $_GET['_error_nonce'], 'plugin-activation-error_' . $plugin )
+	) {
 		$iframe_url = add_query_arg(
 			array(
 				'action'   => 'error_scrape',