Shortcode Shortcode use inside image captions

Hey, this is a wonderful idea and it’s great to see you made it work in such a simple way. Congrats!

My issue is that I really want to use this in image captions because when documenting shortcodes I like to insert screenshots showing the output you’d get with various attributes and having the shortcode example in the caption is the obvious way to display it.

I know it’s an annoying edge case (yo dawg, I heard you like shortcodes) but at the same time it seems like a common need for people using your plugin for it’s main purpose: documenting their shortcodes.

Right now it seems that using [shortcode] in the core [caption] doesn’t work. What I get is the caption with the unprocessed shortcode in it.

I dug around and it seems that the core img_caption_shortcode() runs do_shortcode() recursively on $content, but only after extracting the caption text and storing it in $atts[‘caption’], so shortcodes in caption text aren’t affected. This isn’t crazy since most shortcodes probably screw up the formatting.

I figured out a filter on ‘shortcode_atts_caption’ (filter atts for only caption shortcode) that very carefully enables only the [shortcode] shortcode inside image captions and only runs do_shortcode() if [shortcode] is present!

It seems like a pretty safe thing to use and makes your shortcode work in my captions. Please consider adding it to your plugin since I bet a lot of people would find it useful. Also please let me know if you discover any unintended side effects!

Here’s the code as a Gist in case the code below is broken:
https://gist.github.com/jeremyclarke/213de46aa04c95592d3e

/**
 * Filter Caption shortcode attributes to enable the [shortcode] shortcode inside caption text
 *
 * WP doesn't run do_shortcode on the 'caption' text value parsed out of [caption], which means
 * the [shortcode] shortcode doesn't work.
 *
 * We want [shortcode] to work but not necessarily any other shortcodes, so we will run do_shortcode()
 * only if [shortcode] is present. Running do_shortcode() this way will process all shortcodes
 * so beware any captions that for some reason also have a bad shortcode that will break formatting.
 *
 * @param array $out atts array as determined by WP to be returned after filtering
 * @param array $pairs
 * @param array $atts
 * @return filtered $out atts
 */
function gv_filter_shortcode_atts_caption_shortcode_shortcode($out, $pairs, $atts) {
	/**
	 * If the shortcode shortcode is present then process all shortcodes
	 * Note: This will process ALL shortcodes which could give insane results
	 */
	if (has_shortcode($out['caption'], 'shortcode')) :
		$out['caption'] = do_shortcode($out['caption']);
	endif;
	return $out;
}
add_filter('shortcode_atts_caption', 'gv_filter_shortcode_atts_caption_shortcode_shortcode', 10, 3);

https://wordpress.org/plugins/shortcode-shortcode/