Check for unrestored par()/options()/setwd() changes — cl_check_option

Flags a par(), options(), or setwd() call in R/ that changes state without a paired on.exit() call in the same function frame to restore it. Per the CRAN Cookbook, packages shouldn't permanently change a user's graphical parameters, options, or working directory; if a function has to, it should save the old value and restore it with on.exit() immediately.

Usage

cl_check_option_restoration(path = ".")

Arguments

path: Path to the package root. Defaults to the current directory.

Value

A tibble following the cranlint check-result contract; see AGENTS.md.

Details

setwd() always counts as a change. For par()/options(), a bare call with no arguments, or a call whose only arguments are unnamed (e.g. par("mfrow"), or par(oldpar)/options(oldopts) restoring a previously-saved list) is treated as a query/restore rather than a change and isn't flagged; par(no.readonly = TRUE) is also excluded as it's the standard snapshot-for-later-restore idiom, not a change by itself.

This is a coarse heuristic: it doesn't check that the on.exit() call actually restores the same thing that was changed, or that the restore happens immediately after the change – only that both are present in the same function frame. A change with no enclosing function at all is always flagged, since on.exit() couldn't apply there anyway.

Examples

pkg_dir <- cl_example_pkg(
  r_files = list(foo.R = c(
    "plot_thing <- function() {",
    "  par(mfrow = c(1, 2))",
    "  plot(1)",
    "}"
  ))
)
cl_check_option_restoration(pkg_dir)
#> # A tibble: 1 × 6
#>   check              file     line severity   message           policy_reference
#>   <chr>              <chr>   <int> <ord>      <chr>             <chr>           
#> 1 option_restoration R/foo.R     2 should_fix par() changes st… https://contrib…
unlink(pkg_dir, recursive = TRUE)