wp-includes/class-wp-meta-query.php:192Ensures the 'meta_query' argument passed to the class constructor is well-formed.
$queriesarrayarray public function sanitize_query( $queries ) { $clean_queries = array(); if ( ! is_array( $queries ) ) { return $clean_queries; } foreach ( $queries as $key => $query ) { if ( 'relation' === $key ) { $relation = $query; } elseif ( ! is_array( $query ) ) { continue; // First-order clause. } elseif ( $this->is_first_order_clause( $query ) ) { if ( isset( $query['value'] ) && array() === $query['value'] ) { unset( $query['value'] ); } $clean_queries[ $key ] = $query; // Otherwise, it's a nested query, so we recurse. } else { $cleaned_query = $this->sanitize_query( $query ); if ( ! empty( $cleaned_query ) ) { $clean_queries[ $key ] = $cleaned_query; } } } if ( empty( $clean_queries ) ) { return $clean_queries; } // Sanitize the 'relation' key provided in the query. if ( isset( $relation ) && 'OR' === strtoupper( $relation ) ) { $clean_queries['relation'] = 'OR'; $this->has_or_relation = true; /* * If there is only a single clause, call the relation 'OR'. * This value will not actually be used to join clauses, but it * simplifies the logic around combining key-only queries. */ } elseif ( 1 === count( $clean_queries ) ) { $clean_queries['relation'] = 'OR'; // Default to AND. } else { $clean_queries['relation'] = 'AND'; } return $clean_queries; }Introduced in 4.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-meta-query.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.