_update_posts_count_on_transition_post_status firing for incorrect post types

[sboisvert]

In a Multisite environment the number of posts (of the posts post_type) is tracked by update_posts_count(). This function will do a large select query which can be pretty slow. The problem is that currently _update_posts_count_on_transition_post_status() will trigger no matter what post type is being transitioned, since update_posts_count() only counts the posts post_type we don't need to trigger a count when a post of another post_type is transitioning.

This patch adds the 3rd parameter to the _update_posts_count_on_transition_post_status() and then does a check and returns if the post is not the post post_type

[JPry]

Tweaks to @sboisvert 's patch

[spacedmonkey]

Added some improvements. For backward compatiblity, I added null to the $posts param to make sure if anyone is calling the function in there own code there is no breakage.

Also used get_post_type() as it always returns something.

[jeremyfelt]

Good catch, thanks @sboisvert - this seems like a straight forward fix.

[jeremyfelt]

42021.2.diff​ applies the same restriction to _update_posts_count_on_delete(), which already has access to the post object.

[jeremyfelt]

In 41665:

Multisite: Only update a site's post count when post types of post are updated.

Previously, the query to update the count of published posts would run every time any post type transitioned between a publish/non-published status or was deleted.

Props sboisvert, JPry, spacedmonkey.
Fixes #42021.