`is_home()` returns `true` on BuddyPress pages when checking early hooks

[r-a-y]

If a developer is doing checks for is_home() on an early hook like 'pre_get_posts', is_home() will currently return true on any BuddyPress page (except if a BuddyPress component is set as the front page, in this case, is_home() will return false as expected).

BuddyPress pages should always have is_home set to false on these early hooks.

You can use this code snippet to verify the current behavior:

<?php
add_action(
    'pre_get_posts',
    function( $query ) {
        if ( ! $query->is_main_query() ) {
            return;
        }

        // This returns true on all BuddyPress pages at this juncture.
        // Except for when a BP component page is set as the front page, then this returns false.
        var_dump( $query->is_home() );
    }
);

// Runs later in the WP bootstrap.
add_action( 'wp', function() {
    // This returns false on all BuddyPress pages at this juncture.
    var_dump( is_home() );
} );

Here's the technical rundown as to why is_home() is returning true on BuddyPress pages on early hooks such as the 'pre_get_posts' hook:

BuddyPress rewrite pages are not correctly set as is_singular = true at this juncture: ​https://github.com/WordPress/WordPress/blob/817670fdedda7cab8d01ddbb3e3ca0f0d95db6de/wp-includes/class-wp-query.php#L1035.

This is because BuddyPress pages are not real pages (if we exclude directory pages), so WP's parse query block doesn't take this into account. See ​https://github.com/WordPress/WordPress/blob/817670fdedda7cab8d01ddbb3e3ca0f0d95db6de/wp-includes/class-wp-query.php#L881-L891 where WP actually sets is_page or is_single. BP rewrite rules do not use the query vars that WP is expecting such as 'pagename' or 'name'. So since is_singular is false when on a BP page, is_home is set to true at: ​https://github.com/WordPress/WordPress/blob/817670fdedda7cab8d01ddbb3e3ca0f0d95db6de/wp-includes/class-wp-query.php#L1044.

To address this, we can either set the query vars that WP is expecting such as 'pagename' or 'name' to all our BP rewrite rules or we manually set is_home to the correct value of false when on the 'parse_query' hook. I'm doing the latter since it's the easiest path.

[johnjamesjacoby]

Patch looks good to me. Thanks @r-a-y!

[dcavins]

@r-a-y Was this the underlying issue with the BP Docs ticket recently?

Thanks!

[r-a-y]

No, they are related, but not the underlying issue. The underlying issue with BP Docs was BP Docs's access protection leaking into other WP main queries. That one is a complicated one and both myself and Boone still don't quite understand it thoroughly.