wp-admin/includes files should not contain hooks

[wonderboymusic]

Following up on #30947

There are random actions and filters littered among files like misc.php.
These files contain a bunch of functions that won't work outside of admin context and are typically only loaded in files that have already loaded the admin bootstrap.

These hooks should move to wp-admin/includes/admin-filters.php and wp-admin/includes/ms-admin-filters.php which can load where appropriate in wp-admin/includes/admin.php`.

A lot of these hooks (old media.php) are essentially deprecated.

In 32653:

In the style of #30947 and default-filters.php, add 2 new files to wp-admin/includes:
admin-filters.php
ms-admin-filters.php

There are random actions and filters littered among files like misc.php. These files contain functions that won't work outside of admin context and are typically only loaded in files that have already loaded the admin bootstrap.

See #32529.

In 32671:

Fix inline documentation formatting in wp-admin/includes/admin-filters.php, introduced in [32653].

See #32529.

A few things I'd like to see here:

• Consolidate actions vs. filters
• Column align parameters to make them easier to identify
• Looks like two network_admin_notices need to be moved to ms-default-filters.php

32529.02.patch suggests the following:

• Alphabetize hooks by $tag
• One empty line between hook types
• Two empty lines between hook groups
• Column align a few lines for improved readability

Patch also moves network_admin_notices hooks to ms-default-filters.php.

I have not tested actual hook priorities; this patch is largely cosmetic.

In 32865:

Cleanup (ms-)?admin-filters.php

Props johnjamesjacoby.
Fixes #32529.

This sounds good but broke outputting the Add Media button above the editor in non wp-admin context, see #33257.

Looking through the files from where the actions and filters were moved, several more are sometimes included in non wp-admin context. Some plugins may also include them outside wp-admin.

In that terms seems we should revert this to maintain back-compat.

Since the Editor class is an edge case where we load an admin file potentially on the front end, wouldn't 32529.diff​ work?

Yeah, that works. Don't even need to include ms-admin-filters.php.

Even simpler:

if ( ! function_exists( 'media_buttons' ) ) {
    include( ABSPATH . 'wp-admin/includes/media.php' );
    add_action( 'media_buttons', 'media_buttons' );
}

The back-compat concern is mostly about plugins that include one of these files outside wp-admin. Also things like: https://core.trac.wordpress.org/browser/trunk/src/wp-includes/update.php#L198.

This ticket was mentioned in ​Slack in #core by ocean90. ​View the logs.

Thinking that we can close this.

• https://core.trac.wordpress.org/attachment/ticket/33257/33257.diff fixes core and the known plugins use cases.
• Post on make/core and a mention in the email to plugin authors.