Source

File: wp-includes/class.wp-dependencies.php

protected function recurse_deps( $queue, $handle ) {
		if ( isset( $this->all_queued_deps ) ) {
			return isset( $this->all_queued_deps[ $handle ] );
		}

		$all_deps = array_fill_keys( $queue, true );
		$queues   = array();
		$done     = array();

		while ( $queue ) {
			foreach ( $queue as $queued ) {
				if ( ! isset( $done[ $queued ] ) && isset( $this->registered[ $queued ] ) ) {
					$deps = $this->registered[ $queued ]->deps;
					if ( $deps ) {
						$all_deps += array_fill_keys( $deps, true );
						array_push( $queues, $deps );
					}
					$done[ $queued ] = true;
				}
			}
			$queue = array_pop( $queues );
		}

		$this->all_queued_deps = $all_deps;

		return isset( $this->all_queued_deps[ $handle ] );
	}