is_user_member_of_blogs fetches all user meta keys

[rinatkhaziev]

[33771] introduced performance improvements to is_user_member_of_blog to combat the slowness of get_blogs_of_user

It does so by fetching all meta keys ($meta_key = ''). This makes it challenging to use "get_{$meta_type}_metadata" filter, as there's no good way to tell which part we want to short-circuit or apply special handling to.

The proposed approach is to change the logic do check for the specific blog's capability check name.

Roughly:

<?php
        // No underscore before capabilities in $base_capabilities_key.
        $base_capabilities_key = $wpdb->base_prefix . 'capabilities';
        $site_capabilities_key = $wpdb->base_prefix . $blog_id . '_capabilities';

        if ( 1 === $blog_id ) {
                $has_cap = get_user_meta( $user_id, $base_capabilities_key, true );
        } else {
                $has_cap = get_user_meta( $user_id, $site_capabilities_key, true );
        }

        return is_array( $has_cap );

https://core.trac.wordpress.org/changeset/33771 introduced performance improvements to is_user_member_of_blog to combat the slowness of get_blogs_of_user

It does so by fetching all meta keys ($meta_key = ). This makes it challenging to use "get_{$meta_type}_metadata" filter, as there's no good way to tell which part we want to short-circuit or apply special handling to.

The proposed approach is to change the logic do check for the specific blog's capability check name.

Trac ticket: https://core.trac.wordpress.org/ticket/63989

[wildworks]

This ticket was featured on today's 6.9 Bug Scrub. This ticket has had no activity since the PR was submitted. Testing and feedback are needed to move this ticket forward.

@jonnynews thank you, makes perfect sense. I've applied the suggestions.

[spacedmonkey]

In 60992:

Users: Avoid fetching all user meta keys in is_user_member_of_blog()

In [33771], is_user_member_of_blog() was optimised to improve the performance of get_blogs_of_user().
That change used $meta_key = to fetch all user meta, which can cause unnecessary data loading and makes it difficult to use the get_{$meta_type}_metadata filter. When all meta keys are retrieved, it’s not possible to tell which specific meta value is being requested for short-circuiting or custom handling.

This commit updates the logic to request only the meta key related to the blog’s capability check, reducing overhead and improving compatibility with metadata filters.

Props rinatkhaziev, spacedmonkey.
Fixes #63989.

Committed

[westonruter]

In 60996:

Coding Standards: Remove extra line break which caused PHPCS to cry.

Sniff: Squiz.WhiteSpace.SuperfluousWhitespace.EmptyLines

Follow-up to [60992].

See #63989.