The image_downsize filter in wp_prepare_attachment_for_js throws an undefined offset notice.

[justinbusa]

The following code in the wp_prepare_attachment_for_js function throws an undefined offset notice...

if ( $downsize = apply_filters( 'image_downsize', false, $attachment->ID, $size ) ) {
    if ( ! $downsize[3] )
        continue;

When isset is added, the noticed goes away...

if ( $downsize = apply_filters( 'image_downsize', false, $attachment->ID, $size ) ) {
    if ( ! isset( $downsize[3] ) )
        continue;

[joemcgill]

Good catch @justinbusa. However, wouldn't using isset() there make that conditional return true if $downsize[3] were set to false through a filter on image_downsize? Perhaps using empty() would be better?

[joemcgill]

34437.diff​ iterates on image_downsize.patch​ to use empty() instead of ! isset() to avoid skipping over instances where $downsize[3] has been set to false.

[joemcgill]

Fixed in [39107].