Don’t update core files when you are dealing with shortcode! There is a neat trick you can take advantage of. I know this doesn’t help your particular issue, but here is the trick:
First, find the function definition and the add_shortcode() that gets used in wp-includes/media.php (or wherever). Copy and paste all of that into the functions.php file in your current theme.
Caption Shortcode example:
add_shortcode('wp_caption', 'img_caption_shortcode');
add_shortcode('caption', 'img_caption_shortcode');
/**
* The Caption shortcode.
*
* Allows a plugin to replace the content that would otherwise be returned. The
* filter is 'img_caption_shortcode' and passes an empty string, the attr
* parameter and the content parameter values.
*
* The supported attributes for the shortcode are 'id', 'align', 'width', and
* 'caption'.
*
* @since 2.6.0
*
* @param array $attr Attributes attributed to the shortcode.
* @param string $content Optional. Shortcode content.
* @return string
*/
function img_caption_shortcode($attr, $content = null) {
// Allow plugins/themes to override the default caption template.
$output = apply_filters('img_caption_shortcode', '', $attr, $content);
if ( $output != '' )
return $output;
extract(shortcode_atts(array(
'id' => '',
'align' => 'alignnone',
'width' => '',
'caption' => ''
), $attr));
if ( 1 > (int) $width || empty($caption) )
return $content;
if ( $id ) $id = 'id="' . esc_attr($id) . '" ';
return '<div ' . $id . 'class="wp-caption ' . esc_attr($align) . '" style="width: ' . (10 + (int) $width) . 'px">'
. do_shortcode( $content ) . '<p class="wp-caption-text">' . $caption . '</p></div>';
}
Next, rename the functions so you avoid errors when they are defined twice.
Last, rename the function that the shortcode calls to match the new name of your function. Don’t rename the shortcode. It will simply be overwritten! Now your shortcode will do what you want and it will work wherever your theme is installed!
example of renamed caption code:
add_shortcode('wp_caption', 'MY_VERY_OWN_img_caption_shortcode');
add_shortcode('caption', 'MY_VERY_OWN_img_caption_shortcode');
/**
* The Caption shortcode.
*
* Allows a plugin to replace the content that would otherwise be returned. The
* filter is 'img_caption_shortcode' and passes an empty string, the attr
* parameter and the content parameter values.
*
* The supported attributes for the shortcode are 'id', 'align', 'width', and
* 'caption'.
*
* @since 2.6.0
*
* @param array $attr Attributes attributed to the shortcode.
* @param string $content Optional. Shortcode content.
* @return string
*/
function MY_VERY_OWN_img_caption_shortcode($attr, $content = null) {
// Allow plugins/themes to override the default caption template.
$output = apply_filters('img_caption_shortcode', '', $attr, $content);
if ( $output != '' )
return $output;
extract(shortcode_atts(array(
'id' => '',
'align' => 'alignnone',
'width' => '',
'caption' => ''
), $attr));
if ( 1 > (int) $width || empty($caption) )
return $content;
if ( $id ) $id = 'id="' . esc_attr($id) . '" ';
return '<div ' . $id . 'class="wp-caption ' . esc_attr($align) . '" style="width: ' . (10 + (int) $width) . 'px">'
. do_shortcode( $content ) . '<p class="wp-caption-text">' . $caption . '</p></div>';
}
