R/pkg_dep_graph.R

In andrewGhazi/geryon: simple utility functions

#' Plot dependency graph
#' @description Plot a package's dependency graph, coloring each node by the number of
#'   packages it depends on.
#' @param pkg package string passed to \code{\link[pak:pkg_deps]{pak::pkg_dep}}
#' @param dep_type type of dependencies to look up. Valid values are \code{c("depends",
#'   "imports", "suggests")}
#' @details If you include \code{"suggests"} among the dependency types to look up, be
#'   aware that suggests can be circular / cyclic. If this is detected, the node coloring
#'   will be turned off.
#'
#' @returns a ggplot
#' @examples
#' plot_deps_graph("dplyr") # dplyr has several dependencies
#' plot_deps_graph("rlang") # rlang has only one
#'
#' @export
plot_deps_graph = function(pkg,
                           dep_type = c("depends", "imports", "linkingto")) {

  rlang::check_installed("igraph")
  rlang::check_installed("ggraph")
  rlang::check_installed("grid")
  rlang::check_installed("pals")
  rlang::check_installed("pak")

  dep_type = tolower(dep_type)

  rlang::arg_match(dep_type,
                   values = c("depends", "imports", "suggests", "linkingto"),
                   multiple = TRUE)

  ex = pak::pkg_deps(pkg) |>
    dplyr::select(package, deps) |>
    dplyr::rename(from = package) |>
    tidyr::unnest(deps, names_repair = "unique") |>
    dplyr::rename(to = "package")

  edge_list = ex |>
    dplyr::filter(tolower(type) %in% dep_type) |>
    dplyr::select(from:to) |>
    unique() |>
    dplyr::filter(to != "R")

  edge_vec = purrr::map2(edge_list$from, edge_list$to,
                         \(x,y) c(x,y)) |>
    unlist()

  gr = igraph::make_directed_graph(edge_vec)

  ec = igraph::ecount(gr)

  if ("suggests" %in% dep_type && !igraph::is_acyclic(gr)) {
    cli::cli_alert_warning("Cycle detected among suggested packages. Can't color nodes by number of dependencies.")
    fill_aes = ggplot2::aes(label = name)
    fill_scale = NULL
  } else {
    fill_scale = ggplot2::scale_fill_gradientn(colors = pals::parula(100)[12:97])
    fill_aes = ggplot2::aes(label = name,
                            fill = igraph::neighborhood_size(gr,
                                                             mode = "out",
                                                             order = ec,
                                                             mindist = 1))
  }

  gr |>
    ggraph::ggraph(ifelse(ec > 1, "stress", "tree")) +
    ggraph::geom_edge_link(arrow = grid::arrow(length = grid::unit(1.5, "mm"),
                                               type = "closed"),
                           ggplot2::aes(end_cap = ggraph::label_rect(node2.name)),
                           color = "#222222") +
    ggraph::geom_node_label(fill_aes) +
    fill_scale +
    ggplot2::theme_dark() +
    ggplot2::theme(axis.title        = ggplot2::element_blank(),
                   axis.text         = ggplot2::element_blank(), axis.ticks = ggplot2::element_blank(),
                   plot.background   = ggplot2::element_rect(fill = "#444444"),
                   legend.background = ggplot2::element_rect(fill = "#666666"),
                   legend.ticks      = ggplot2::element_line(colour = "#333333")) +
    ggplot2::labs(fill = "n_deps")
}