[NSFW] Got an error “PHP Fatal error: Uncaught TypeError: count()”

I’m running 10 WordPress sites and I’ve got following error on a few sites of them.

`[08-Oct-2021 02:37:19 UTC] PHP Fatal error:  Uncaught TypeError: count(): Argument #1 ($var) must be of type Countable|array, string given in /home/matsu/Sites/teraren.com/diary/wp-content/plugins/google-sitemap-generator/sitemap-builder.php:475
Stack trace:
#0 /home/matsu/Sites/teraren.com/diary/wp-includes/class-wp-hook.php(303): GoogleSitemapGeneratorStandardBuilder->Index(Object(GoogleSitemapGenerator))
#1 /home/matsu/Sites/teraren.com/diary/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters('', Array)
#2 /home/matsu/Sites/teraren.com/diary/wp-includes/plugin.php(470): WP_Hook->do_action(Array)
#3 /home/matsu/Sites/teraren.com/diary/wp-content/plugins/google-sitemap-generator/sitemap-core.php(1623): do_action('sm_build_index', Object(GoogleSitemapGenerator))
#4 /home/matsu/Sites/teraren.com/diary/wp-content/plugins/google-sitemap-generator/sitemap-loader.php(327): GoogleSitemapGenerator->ShowSitemap(Array)
#5 /home/matsu/Sites/teraren.com/diary/wp-content/plugins/google-sitemap-generator/sitemap-loader.php(202): GoogleSitemapGeneratorLoader::CallShowSitemap('params=')
#6 /home/matsu/Sites/teraren.com/diary/wp-includes/class-wp-hook.php(301): GoogleSitemapGeneratorLoader::DoTemplateRedirect()
#7 /home/matsu/Sites/teraren.com/diary/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(true, Array)
#8 /home/matsu/Sites/teraren.com/diary/wp-includes/plugin.php(470): WP_Hook->do_action(Array)
#9 /home/matsu/Sites/teraren.com/diary/wp-includes/template-loader.php(13): do_action('template_redire...')
#10 /home/matsu/Sites/teraren.com/diary/wp-blog-header.php(19): require_once('/home/matsu/Sit...')
#11 /home/matsu/Sites/teraren.com/diary/index.php(17): require('/home/matsu/Sit...')
#12 {main}
  thrown in /home/matsu/Sites/teraren.com/diary/wp-content/plugins/google-sitemap-generator/sitemap-builder.php on line 475

I wrote a patch to avoid the error.

% diff -u /path/to/old/sitemap-builder.php /path/to/new/sitemap-builder.php
--- /home/matsu/Sites/teraren.com/je1wfv/wp-content/plugins/google-sitemap-generator/sitemap-builder.php	2021-10-08 02:38:49.268861006 +0000
+++ /home/matsu/Sites/teraren.com/matsu/blog/wp-content/plugins/google-sitemap-generator/sitemap-builder.php	2021-09-03 09:01:22.833828604 +0000
@@ -472,7 +472,7 @@
 		}

 		$pages = $gsg->GetPages();
-		if(count($pages) > 0) {
+		if(is_array($pages) && count($pages) > 0) {
 			foreach($pages AS $page) {
 				if($page instanceof GoogleSitemapGeneratorPage && $page->GetUrl()) {
 					$gsg->AddSitemap("externals", null, $blogUpdate);

Root cause is that the original code expects $pages is an array but the content of the variable is string.

My server environment.

$ php -v
PHP 8.0.8 (cli) (built: Jul  7 2021 17:35:32) ( NTS )
Copyright (c) The PHP Group
Zend Engine v4.0.8, Copyright (c) Zend Technologies
    with Zend OPcache v8.0.8, Copyright (c), by Zend Technologies

Wordpress 5.8.1

I’d appriciate if the patch is merged.

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