Warning: urldecode() expects parameter 1 to be string, array given

[krypsin]

Issue
Sentry has logged an issue here: ​https://sentry.io/share/issue/22e714bd19904fb29eb54fe8fb3c5f7b/

/wp/wp-includes/class-wp-query.php in WP_Query::get_posts at line 2203

<?php
$q['author'] = addslashes_gpc( '' . urldecode( $q['author'] ) );

Warning: urldecode() expects parameter 1 to be string, array given

This happens on a fresh installation of WordPress.

To replicate

1. Setup a fresh installation of WordPress (no plugins or anything extra)
2. Visit the WP URL with the query ?author%5B%5D=%5BFiltered%5D3 to replicate the issue.

[knutsp]

Hello @krypsin, welcome to Trac and thanks for the ticket.

The author parameter only takes an integer for author_id. For arrays use author__in.

It seems to me the emitted warning is correct.

[SergeyBiryukov]

Hi there, welcome to WordPress Trac!

Thanks for the report, we're already tracking this issue in #17737.