evalFuture(): disable querying of availableCores() for now

Author: HenrikBengtsson

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future
-Version: 1.34.0-9208
+Version: 1.34.0-9209
 Title: Unified Parallel and Distributed Processing in R for Everyone
 Imports:
     digest,

R/backend_api-SequentialFutureBackend-class.R

@@ -24,9 +24,6 @@ launchFuture.SequentialFutureBackend <- function(backend, future, ...) {
     on.exit(mdebugf("launchFuture() for %s ... DONE", commaq(class(backend))))
   }
 
-  ## Launch future
-  future[["state"]] <- "running"
-
   ## Get future
   data <- getFutureData(future, debug = debug)
 
@@ -36,8 +33,9 @@ launchFuture.SequentialFutureBackend <- function(backend, future, ...) {
   earlySignal <- backend[["earlySignal"]]
   if (!is.null(earlySignal)) future[["earlySignal"]] <- earlySignal
 
+  ## Launch future
+  future[["state"]] <- "running"
   future[["result"]] <- evalFuture(data)
-  
   future[["state"]] <- "finished"
 
   if (debug) mdebugf("%s started (and completed)", class(future)[1])

R/backend_api-evalFuture.R

@@ -569,34 +569,36 @@ evalFuture <- function(
     if ("threads" %in% reset) {
       on.exit(setNumberOfThreads(old), add = TRUE)
     }
-  }      
+  }
 
 
   ## -----------------------------------------------------------------
   ## Limit nested parallelization
   ## -----------------------------------------------------------------
+  ...future.ncores <- NA_integer_
+  
   ## (a) Identify default number of cores - ignoring plan settings
   ## FIXME: Can the results here be memoized? Can the results be
   ## precalculated and stored in the strategy stack? /HB 2025-02-17
-  ...future.ncores <- local({
-    ans <- NA_integer_
-    
-    options(parallelly.availableCores.fallback = 1L)
-    ## NOTE: availableCores() is expensive
-    ncores <- availableCores(which = "all")
-    ncores <- ncores[ncores != ncores["system"]]
-    ncores <- ncores[setdiff(names(ncores), c("_R_CHECK_LIMIT_CORES_", "Bioconductor"))]
-    n_ncores <- length(ncores)
-    if (n_ncores > 0) {
-      if (n_ncores > 1) {
-        ncores <- ncores[setdiff(names(ncores), "fallback")]
-      }
+  if (FALSE) {
+    ...future.ncores <- local({
+      ans <- NA_integer_
+      options(parallelly.availableCores.fallback = 1L)
+      ## NOTE: availableCores() is expensive
+      ncores <- availableCores(which = "all")
+      ncores <- ncores[setdiff(names(ncores), c("system", "_R_CHECK_LIMIT_CORES_", "Bioconductor"))]
+      n_ncores <- length(ncores)
       if (n_ncores > 0) {
-        ans <- min(ncores, na.rm = TRUE)
+        if (n_ncores > 1) {
+          ncores <- ncores[setdiff(names(ncores), "fallback")]
+        }
+        if (n_ncores > 0) {
+          ans <- min(ncores, na.rm = TRUE)
+        }
       }
-    }
-    ans
-  })
+      ans
+    })
+  }
 
   ## Use the next-level-down ("popped") future strategy
   plan(strategiesR, .cleanup = FALSE, .init = FALSE)