Post meta revisions

add_action( 'save_post',                'plugin_foo_save_post', 10, 2 );
add_action( 'wp_restore_post_revision', 'plugin_foo_restore_revision', 10, 2 );

function plugin_foo_restore_revision( $post_id, $revision_id ) {

    $post = get_post( $post_id );
    $revision = get_post( $revision_id );

    if ( post_type_supports( $post->post_type, 'my_feature' ) ) {

        $meta = get_metadata( 'post', $revision->ID, 'my_feature', true );
        if ( !empty( $meta ) )
            update_metadata( 'post', $post_id, 'my_feature', $meta );

    }

}

function plugin_foo_save_post( $post_id, $post ) {

    if ( $parent_id = wp_is_post_revision( $post_id ) ) {

        $parent = get_post( $parent_id );

        if ( post_type_supports( $parent->post_type, 'my_feature' ) ) {
            $meta = get_post_meta( $parent->ID, 'my_feature', true );
            if ( !empty( $meta ) )
                add_metadata( 'post', $post_id, 'my_feature', $meta );
        }

    }

}