Ensure front-end hooks are only registered on main query

[christianwach]

Overview

It has been reported that the Benevolent Pro theme makes a sub-query prior to the main query. This unsets the value of get_query_var( 'page' ) and thus the CiviCRM basepage fails to render CiviCRM content. Given that other themes might do something similar, we should accommodate this sort of behaviour. The solution is to ensure that front-end hooks are only registered on main query.

See the issue on Lab for further details.

Before

Making a sub-query prior to the main query unsets the value of get_query_var( 'page' ) and CiviCRM content fails to render.

After

Making a sub-query prior to the main query no longer unsets the value of get_query_var( 'page' ) and CiviCRM content renders as expected.

Steps to reproduce

Add this to a plugin or functions.php file:

add_action( 'init', 'blah_init' );
function blah_init() {
	$args = array( 'posts_per_page' => 3 );
	$titles = [];
	$query = new WP_Query( $args );
	if ( $query->have_posts() ) {
		while ( $query->have_posts() ) {
			$query->the_post();
			$titles[] = get_the_title();
		}
		// Do something with titles.
	}
	wp_reset_postdata();
}

Boom.

[mattwire]

@kcristiano @mecachisenros Can you confirm this is correct?

[kcristiano]

@christianwach I can reproduce the error with the attached code. Apllying the patch doies fix it.

There may be other cases where we cannot fix, if a theme is really doing something unexpected, we may not catch it. This is a good improvement.

• (r-explain) PASS
• (r-test) None
• (r-code) PASS
• (`r-doc) PASS None needed
• (r-maint) PASS
• (r-run) : PASS recreated the error, applied patch and it was fixed. Ran with 4 other themes with and withut the patch, worked fine in all instances.
• (r-user) PASS
• (r-tech) PASS