[wp-trac] [WordPress Trac] #29443: wp_get_attachment_image 4st. parameter $attr should be reference &$attr

[WordPress Trac]

#29443: wp_get_attachment_image 4st. parameter $attr should be reference &$attr
-------------------------+-------------------------------------------------
 Reporter:               |      Owner:
  heddesheimer           |     Status:  new
     Type:  defect       |  Milestone:  Awaiting Review
  (bug)                  |    Version:  3.9.2
 Priority:  normal       |   Keywords:  media, thumbnail,
Component:  Media        |  wp_get_attachment_image, attr
 Severity:  normal       |
  Focuses:               |
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 When I tried to hook in to wp_get_attachment_image() in media.php to
 override the html of the post_thumbnail, I found that the $attr variable
 never passed any values to the hooked callback function.

 This makes sense, as arrays are created as copies in PHP functions,
 therefore the 4st. parameter must be &$attr instead of just $attr. When I
 changes that in the function, my $attr values all gets passed fine to the
 intercepting function that uses the hook.

 To reproduce the problem:
 add a filter like this to your plugin/theme:

     add_filter( 'post_thumbnail_html', 'my_post_thumbnail_html', 10, 5 );

 Then try to show the passed attributes in the callback function like this:

     function my_post_thumbnail_html($html, $post_id, $post_thumbnail_id,
 $size, $attr)
     {
         print_r($attr); exit;
     }

 You will see that nothing is displayed. When you change the 4st. parameter
 of wp_get_attachment_image in wp-includes/media.php to &$attr, it will
 show the attributes like this:

     Array ( [src] => http://testing.local/wordpress296/wp-
 content/uploads/2014/08/about-image.jpg [class] => attachment-450x300 wp-
 post-image [alt] => alternative text )

 which is the expected result for the filter.

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Ticket URL: <https://core.trac.wordpress.org/ticket/29443>
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