Check an R package for stale imports and suggests

check_stale_imports_suggests.R

# run from the package top level
check_stale_imports_suggests <- function() {

  # helper function: removes extra characters
  # from strings read by read.dcf
  clean_up <- function(string) {
    string <- gsub("\n", "", string)
    string <- gsub("\\(.+\\)", "", string)
    string <- unlist(strsplit(string, ","))
    string <- trimws(string)
  }

  desc <- read.dcf("DESCRIPTION", all = TRUE)

  # look for use of imported packages
  imp <- clean_up(desc$Imports)
  if (length(imp) == 0L) message("No Imports: entries found")
  if (length(imp) >= 1) {
    imp_res <- rep("FALSE", length(imp))
    for (i in 1:length(imp)) {
      args <- paste("-r -e '", imp[i], "' *", sep = "")
      g_imp <- system2("grep", args, stdout = TRUE)
      # always found once in DESCRIPTION, hence > 1
      if (length(g_imp) > 1L) imp_res[i] <- TRUE
    }
  }

  # look for use of suggested packages
  sug <- clean_up(desc$Suggests)
  if (length(sug) == 0L) message("No Suggests: entries found")
  if (length(sug) >= 1) {
    sug_res <- rep("FALSE", length(sug))
    for (i in 1:length(sug)) {
      args <- paste("-r -e '", sug[i], "' *", sep = "")
      g_sug <- system2("grep", args, stdout = TRUE)
      # always found once in DESCRIPTION, hence > 1
      if (length(g_sug) > 1L) sug_res[i] <- TRUE
    }
  }

  # arrange output in easy to read format
  role <- c(rep("Imports", length(imp)), rep("Suggests", length(sug)))
  
  return(data.frame(
    pkg = c(imp, sug),
    role = role,
    found = c(imp_res, sug_res)))
}