Use library path of a fresh R session

[renkun-ken]

In the documentation of r_session, the description libpath argument says

libpath: Library path for the subprocess. By default the same as the current library path. I.e. not necessarily the library path of a fresh R session.)

I wonder if it is possible to keep the library path of a fresh R session instead of propagating from the main session?

My motivation is that I need to start an R session from a specific working directory so that the folder .Rprofile is respected (e.g. renv projects or any other startup customization) so that I can call session$run() with the proper R libpath setup specific to that directory. In this use case, it is best that the spawned R session should behave exactly the same as if the session is a fresh session started from the specific working directory.

[renkun-ken]

In a working directory without user .Rprofile

callr::r(function() .libPaths(), libpath = character(), system_profile = TRUE, user_profile = TRUE)

works properly.

But if I create a folder where a user .Rprofile with the following

library(data.table)
.libPaths(
  c(normalizePath("~/test/test1/R"), .libPaths())
)

and run the following in the master session:

setwd(normalizePath("~/test/test1"))
callr::r(function() .libPaths(), libpath = character(), system_profile = TRUE, user_profile = TRUE)

the following error occurs:

Error in `get_result(output = out, options)`:
! callr subprocess failed: could not start R, exited with non-zero status, has crashed or was killed
ℹ See `$stderr` for standard error.
Type .Last.error to see the more details.
Backtrace:
1: stop(cond)
2: throw(new_callr_crash_error(output, killmsg))
3: get_result(output = out, options)
4: r(func, args = args, libpath = libpath, repos = repos, cmdargs = cmdargs, 
5: callr::r_vanilla(function() .libPaths(), libpath = character(),

[gaborcsardi]

Yeah, it would make sense to have an option for this.