WordPress – id set in the arguments array for sidebar Defaulting to “sidebar-1”

Since WordPress updated to 4.2.0, a register_sidebar id error has appeared across several WordPress sites, and is present in some of its most popular themes. Whilst you’re likely only to see this in debug mode, it’s a quick fix and easily remedied.

register_sidebar error

Here’s an example of the WordPress error you might see;

id

was set in the arguments array for the "Blog Sidebar" sidebar. Defaulting to "sidebar-1".

Manually set the id to "sidebar-1" to silence this notice and keep existing sidebar content.

Please see Debugging in WordPress for more information.
(This message was added in version 4.2.0.) in <b>/.../.../.../www/wp-includes/functions.php</b> on line <b>3560</b>

WP codex under WordPress register_sidebar – error explains that;

“If you do not set the id argument value, you will get E_USER_NOTICE messages in debug mode, starting with version 4.2.”

Finding register_sidebar

So how do you fix this? First of all do a search for register_sidebar within your theme folder, it’s most likely to be in the main functions.php file. You’ll likely find a block of code defining your sidebar areas. Below is an example from the popular WordPress theme Salient;

register_sidebar error code

if(function_exists('register_sidebar')) {
register_sidebar(array('name' => 'Blog Sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('name' => 'Page Sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('name' => 'WooCommerce Sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('name' => 'Footer Area 1', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('name' => 'Footer Area 2', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
}

Here’s how the code should have been written, with an id set for each new sidebar.

register_sidebar code fix

if(function_exists('register_sidebar')) {
register_sidebar(array('id' => 'blog-sidebar', 'name' => 'Blog Sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('id' => 'page-sidebar', 'name' => 'Page Sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('id' => 'woocommerce-sidebar', 'name' => 'WooCommerce Sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('id' => 'footer-area-1', 'name' => 'Footer Area 1', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
register_sidebar(array('id' => 'footer-area-2', 'name' => 'Footer Area 2', 'before_widget' => '<div id="%1$s" class="widget %2$s">','after_widget'  => '</div>', 'before_title'  => '<h4>', 'after_title'   => '</h4>'));
}

Adding an id to each register_sidebar array e.g. ‘id’ => ‘blog-sidebar’, should fix the issue. If using a premium theme, create a support ticket for the change to be added as part of the next update. Otherwise, you can make the change in functions.php of a child theme, so changes to the main theme files don’t wipe out your changes.

Need help – WordPress

If you need help with your WordPress site give us a call or contact us via our Contact form. We’re based off the Essex coast, and are able to offer quick support to many Essex, Norfolk, and London based businesses.