Skip package installation in `renv::use()` if packages already installed.

[noamross]

I have been starting to use renv::use() for utility scripts so they self-install dependencies, like so

#!/usr/bin/env Rscript

script_version = "0.2.0"
script_lib =  tools::R_user_dir(paste0("myScript_", script_version), "data")
if (!dir.exists(script_lib)) dir.create(script_lib)

if (!requireNamespace("renv", quietly = TRUE)) {
    install.packages("renv")
}

options(repos = c(rOpenSci = "https://ropensci.r-universe.dev", getOption("repos")))

renv::use(
  "docopt@0.7.0",
  "rnaturalearthhires",
  verbose = TRUE,
  sandbox = FALSE,
  library = script_lib
)

library(docopt)
library(rnaturalearthhires)

sessionInfo()

The idea is that the script has a self-contained library and is portable across machines without interfering with the user library (analagous to uv tool run). However, I note that renv::use() always installs the packages, even if they are already in the library. This is fast when using the renv package cache, but still adds startup overhead. Would it be possible for use() to skip installation if the correct package version exists in the library directory already?

[kevinushey]

Thanks for the feature request -- I can take a look.

[kevinushey]

Thanks! I've implemented something in 1093f0f; can you let me know if that seems sufficient?

[noamross]

Looks like it! Network calls are avoided, and the total time of renv::use() was consistently cut down from ~0.016s to ~0.008s. Thanks.