Pass $instance variable to post_gallery, post_playlist filters

[justincwatt]

gallery_shortcode() and wp_playlist_shortcode() keep track of the number of times they're called with a static variable, $instance. This variable is important so that content (e.g. CSS) can be included only on the first function call, or so that unique IDs can be generated for HTML tags.

The problem is that this instance variable is not made available to their respective filters, post_gallery and post_playlist, unlike their shortcode siblings, wp_audio_shortcode() and wp_video_shortcode(), both of which pass the instance variable to their filters. Which means that any plugins seeking to adapt the behavior of these shortcodes do not have access to the same data as core.

[justincwatt]

Passing $instance variable to post_gallery and post_playlist filters

[SergeyBiryukov]

In 31304:

Pass the current shortcode instance ID to post_gallery and post_playlist filters.

props justincwatt.
fixes #31151.

[SergeyBiryukov]

In 31305:

Rename $instances to $instance in wp_audio_shortcode() and wp_video_shortcode() for consistency with gallery_shortcode() and wp_playlist_shortcode().

see #31151.

[ninnypants]

Add changelogs

[ninnypants]

There's a patch to add change log entries

[SergeyBiryukov]

Good catch, thanks.

[DrewAPicture]

In 31309:

Add changelog entries to the post_gallery and post_playlist hook docs for the $instance variable that was added in [31304].

Props ninnypants for the initial patch.
Fixes #31151.