Media: Fix WP_Site_Icon 'width ' typo causing non-square site icon subsizes

[NoumaanAhamed]

Summary

Fixes an issue where site icon subsizes (site_icon-192, site_icon-32, etc.) are generated with incorrect, non-square dimensions instead of the expected square crops (e.g. 192×192, 32×32).

Root Cause

In src/wp-admin/includes/class-wp-site-icon.php, the WP_Site_Icon::additional_sizes() method defines subsize entries with the array key 'width ' (containing a trailing space) instead of 'width':

$only_crop_sizes[ 'site_icon-' . $size ] = array(
    'width ' => $size,  // ← trailing space in key
    'height' => $size,
    'crop'   => true,
);

The downstream consumer in src/wp-includes/media.php (wp_get_registered_image_subsizes()) reads the width using the correct key 'width' (no space):

if ( isset( $additional_sizes[ $size_name ]['width'] ) ) {
    $size_data['width'] = (int) $additional_sizes[ $size_name ]['width'];
}

Because the keys don't match, the isset() check fails, width remains 0, and the image editor never receives a width constraint. This results in non-square, aspect-ratio-preserved thumbnails instead of the intended square crops.

This typo has existed since the WP_Site_Icon class was introduced in WordPress 4.3.

Solution

• Changed 'width ' to 'width' in the subsize definition array inside WP_Site_Icon::additional_sizes().
• Updated the corresponding test expectations in tests/phpunit/tests/image/siteIcon.php which mirrored the same typo.

Testing

1. Set up a local WordPress dev environment (e.g. using wp-env, Local, or Docker).
2. Upload a non-square image (e.g. a 1200×800 landscape photo) via Media → Add New.
3. Set it as the site icon without cropping:

   wp option update site_icon <attachment_id>

4. Regenerate the attachment metadata with the site icon filters enabled (this is necessary because by default WP-CLI does not load admin/customizer classes containing site icon filters):

   wp eval '
   require_once ABSPATH . "wp-admin/includes/class-wp-site-icon.php";
   $wp_site_icon = new WP_Site_Icon();
   add_filter( "intermediate_image_sizes_advanced", array( $wp_site_icon, "additional_sizes" ) );
   $metadata = wp_generate_attachment_metadata( <attachment_id>, get_attached_file( <attachment_id> ) );
   wp_update_attachment_metadata( <attachment_id>, $metadata );
   '

5. Inspect the generated subsizes:

   wp post meta get <attachment_id> _wp_attachment_metadata

6. Verify that site_icon-270, site_icon-192, site_icon-180, and site_icon-32 are now square crops (e.g. 192×192, 32×32). Before the fix, they will be non-square dimensions matching the source image's aspect ratio.

---

Trac Ticket: https://core.trac.wordpress.org/ticket/65345

---

Test Case	Expected / Result	Status
test_additional_sizes — subsizes use 'width' key	Array keys match 'width' (no trailing space)	✅ Passed
test_additional_sizes_with_filter — custom sizes use 'width' key	Array keys match 'width' (no trailing space)	✅ Passed
Site icon subsizes are square crops after regeneration	site_icon-192 = 192×192, site_icon-32 = 32×32, etc.	✅ Passed
get_site_icon_url() returns correct subsize URL	Returns subsize URL instead of falling back to full image	✅ Passed

Use of AI Tools

AI assistance: No

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Props mohamedahamed, peterwilsoncc.

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