R_PROFILE_USER cannot be set in `env` for `callr::r`

[MilesMcBain]

callr::r(
    function() {
    print(Sys.getenv("MY_ENV"))
    print(Sys.getenv("R_PROFILE_USER"))
    },
    user_profile = TRUE,
    env = c(
        "R_PROFILE_USER" = "~/.Rprofile",
        "MY_ENV" = "MILES"
    ),
    show = TRUE
)
#> [1] "MILES"
#> [1] ""
#> [1] ""

^{Created on 2021-03-31 by the reprex package (v0.3.0)}

I was expecting this to work, in combination with user_profile = TRUE so that I could set the profile for the session to a specific file.

[gaborcsardi]

callr::r() uses the profile to make sure the config of the child process matches the current process, so you can't point it to a different file. OTOH it tries to copy the current settings, so this works:

tmp <- tempfile()
cat("foo <- 42\n", file = tmp)
Sys.setenv(R_PROFILE_USER = tmp)

callr::r(function() foo, user_profile = FALSE)
#> Error: callr subprocess failed: object 'foo' not found
#> Type .Last.error.trace to see where the error occurred

callr::r(function() foo, user_profile = TRUE)
#> [1] 42

[gaborcsardi]

@MilesMcBain Is this workaround OK for your use case?

I could try to consider env as well, before using the current value of R_PROFILE_USER, but the profile management is already pretty difficult. Although well tested, this is still not something that is easy to change.

Alternatively, we can document the current behavior.

[MilesMcBain]

I think the curent workaround is fine if documented.

It can make my example work with this and It doesn't work for my usecase but I think that is due to {targets}.

[gaborcsardi]

Actually, I think I fixed it, hopefully without breaking anything else...