Don't use withr and pass env to the processx call directly

Author: cderv

DESCRIPTION

@@ -30,7 +30,6 @@ Imports:
     rstudioapi,
     tools,
     utils,
-    withr,
     xfun,
     yaml (>= 2.3.10)
 Suggests: 
@@ -54,7 +53,8 @@ Suggests:
     thematic,
     tidyverse,
     tinytable,
-    whoami
+    whoami,
+    withr
 VignetteBuilder: 
     quarto
 Config/testthat/edition: 3

R/quarto.R

@@ -133,18 +133,32 @@ quarto_run <- function(
   ...,
   .call = rlang::caller_env()
 ) {
+  # To store any environment variables to pass to the process
+  custom_env <- NULL
+
   # This is required due to a bug in QUARTO CLI, fixed only in 1.8+
   # https://github.com/quarto-dev/quarto-cli/pull/12887
-  custom_env <- NULL
   if (!quarto_available(min = "1.8.13")) {
-    custom_env <- c("current", QUARTO_R = R.home("bin"))
+    custom_env <- c(custom_env, QUARTO_R = R.home("bin"))
   }
+
+  # handle session .libpaths() for background session
+  # It needs to be passed if .libPaths() was modified in the current R session
+  # (e.g. to install dev package in a temporary library)
   opt_in_libpath <- getOption("quarto.use_libpaths", TRUE)
   if (isTRUE(opt_in_libpath) && !is.null(libpaths)) {
-    withr::local_envvar(list(
+    custom_env <- c(
+      custom_env,
       R_LIBS = paste(libpaths, collapse = .Platform$path.sep)
-    ))
+    )
   }
+  
+  # This is required because `"current"` only is not supported by processx
+  # FIXME: https://github.com/r-lib/processx/issues/399
+  if (!is.null(custom_env)) {
+    custom_env <- c("current", custom_env)
+  }
+
   res <- withCallingHandlers(
     processx::run(
       quarto_bin,