wp-includes/class-wp.php:606Sets the query string property based off of the query variable property.
One hook fires while WP::build_query_string() runs, in this order:
Filters the query string before parsing.
public function build_query_string() { $this->query_string = ''; foreach ( (array) array_keys( $this->query_vars ) as $wpvar ) { if ( '' !== $this->query_vars[ $wpvar ] ) { $this->query_string .= ( strlen( $this->query_string ) < 1 ) ? '' : '&'; if ( ! is_scalar( $this->query_vars[ $wpvar ] ) ) { // Discard non-scalars. continue; } $this->query_string .= $wpvar . '=' . rawurlencode( $this->query_vars[ $wpvar ] ); } } if ( has_filter( 'query_string' ) ) { // Don't bother filtering and parsing if no plugins are hooked in. /** * Filters the query string before parsing. * * @since 1.5.0 * @deprecated 2.1.0 Use {@see 'query_vars'} or {@see 'request'} filters instead. * * @param string $query_string The query string to modify. */ $this->query_string = apply_filters_deprecated( 'query_string', array( $this->query_string ), '2.1.0', 'query_vars, request' ); parse_str( $this->query_string, $this->query_vars ); } }Introduced in 2.0.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.