R/lock2desc.R

In zkamvar/vise: Package Discovery and Management Based on 'renv'

#' convert a lockfile to a description file
#'
#' By default, this will take in a lockfile or a desc object and convert it to 
#' an equivalent DESCRIPTION file for use with packages that check for system
#' dependencies.
#'
#' @param lockfile the path to the renv lockfile OR a [desc::description()] object.
#' @param desc the path to the new description file
#' @return the path to the new description file
#'
#' @export
#' @examples
#' lock <- system.file("renv.lock", package = "vise")
#' lock2desc(lock)
lock2desc <- function(lockfile, desc = tempfile()) {
  if (!requireNamespace("desc", quietly = TRUE)) {
    stop("The {desc} package is required for this function")
  }
  if (basename(desc) != "DESCRIPTION" && !file.exists(desc)) {
    # if we have a tempfile, we need to create it
    dir.create(desc)
    out <- file.path(desc, "DESCRIPTION")
  } else {
    out <- desc
  }
  if (inherits(lockfile, "description")) {
    d <- lockfile
  } else {
    lock <- get_lockfile(lockfile) #asNamespace("renv")$lockfile(lockfile)
    dat <- lock$Packages
    pkg <- names(dat)
    versions <- paste("==", vapply(dat, function(p) p$Version, character(1)))
    deps <- data.frame(type = "Imports", package = pkg, version = versions)
    d <- desc::description$new("!new")
    d$set_deps(deps)
  }
  d$write(file = out)
  out
}