guard against invalid mc.cores values (#2086)

rstudio · Feb 4, 2025 · ff88572 · ff88572
1 parent 731463e
commit ff88572
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Showing 2 changed files with 30 additions and 6 deletions.
diff --git a/R/parallel.R b/R/parallel.R
@@ -4,16 +4,19 @@ renv_parallel_cores <- function() {
   if (renv_platform_windows())
     return(1L)
 
-  value <- config$updates.parallel()
-  if (identical(value, TRUE)) {
-    parallel <- requireNamespace("parallel", quietly = TRUE)
-    getOption("mc.cores", default = if (parallel) 2L else 1L)
-  } else if (identical(value, FALSE)) {
+  parallel <- config$updates.parallel()
+  value <- if (identical(parallel, TRUE)) {
+    requireNamespace("parallel", quietly = TRUE)
+    getOption("mc.cores", default = 2L)
+  } else if (identical(parallel, FALSE)) {
     1L
   } else {
-    as.integer(value)
+    parallel
   }
 
+  ok <- is.numeric(value) && length(value) == 1L && !is.na(value)
+  if (ok) value else 1L
+
 }
 
 renv_parallel_exec <- function(data, callback) {

diff --git a/tests/testthat/test-update.R b/tests/testthat/test-update.R
@@ -112,3 +112,24 @@ test_that("can upgrade gitlab", {
   expect_equal(updated$skeleton$RemoteSha, latest$RemoteSha)
 
 })
+
+test_that("we guard against invalid mc.cores values", {
+
+  renv_scope_options(renv.config.updates.parallel = TRUE)
+
+  local({
+    renv_scope_options(mc.cores = 4L)
+    expect_equal(renv_parallel_cores(), 4L)
+  })
+
+  local({
+    renv_scope_options(mc.cores = NA)
+    expect_equal(renv_parallel_cores(), 1L)
+  })
+
+  local({
+    renv_scope_options(mc.cores = "oops")
+    expect_equal(renv_parallel_cores(), 1L)
+  })
+
+})