BUG FIX: The built-in checks for added, removed, or modified graphical devices, could produce false positives [#788]

Author: HenrikBengtsson

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future
-Version: 1.49.0-9013
+Version: 1.49.0-9014
 Title: Unified Parallel and Distributed Processing in R for Everyone
 Depends:
     R (>= 3.2.0)

NEWS.md

@@ -11,6 +11,13 @@
    fails to communicate with one or more of the parallel workers, it
    will now close any socket connections that remain open towards such
    cluster nodes.
+
+ * The built-in checks for added, removed, or modified graphical
+   devices, could produce false positives, complaining about "A future
+   expression must close any opened devices and must not close devices
+   it did not open. Details: 1 devices differ: index=2, before='NA',
+   after=''". The problem was that it did not prune the empty 'after'
+   before the check.
 
 
 # Version 1.49.0 [2025-05-08]

R/backend_api-evalFuture.R

@@ -343,6 +343,12 @@ diff_globalenv <- function(before, after = names(.GlobalEnv)) {
 
 
 diff_devices <- function(before, after = base::.Devices) {
+  ## Prune
+  before <- unlist(before)
+  before <- before[before != ""]
+  after <- unlist(after)
+  after <- after[after != ""]
+  ## Compare
   n_before <- length(before)
   n_after <- length(after)
   n <- max(n_before, n_after)
@@ -353,7 +359,7 @@ diff_devices <- function(before, after = base::.Devices) {
     data[[kk]] <- data.frame(index = kk, before = before_kk, after = after_kk, identical = identical(after_kk, before_kk))
   }
   data <- do.call(rbind, data)
-  data <- data[!data[["identical"]], ]
+    data <- data[!data[["identical"]], ]
   if (nrow(data) == 0L) NULL else data
 }