bbp_update_topic_revision_log( mixed $args = '' )

function bbp_update_topic_revision_log( $args = '' ) {

	// Parse arguments against default values
	$r = bbp_parse_args( $args, array(
		'reason'      => '',
		'topic_id'    => 0,
		'author_id'   => 0,
		'revision_id' => 0
	), 'update_topic_revision_log' );

	// Populate the variables
	$r['reason']      = bbp_format_revision_reason( $r['reason'] );
	$r['topic_id']    = bbp_get_topic_id( $r['topic_id'] );
	$r['author_id']   = bbp_get_user_id ( $r['author_id'], false, true );
	$r['revision_id'] = (int) $r['revision_id'];

	// Get the logs and append the new one to those
	$revision_log                      = bbp_get_topic_raw_revision_log( $r['topic_id'] );
	$revision_log[ $r['revision_id'] ] = array( 'author' => $r['author_id'], 'reason' => $r['reason'] );

	// Finally, update
	return update_post_meta( $r['topic_id'], '_bbp_revision_log', $revision_log );
}