Drop a few unneeded unique()

Author: HenrikBengtsson

R/backend_api-Future-class.R

@@ -142,7 +142,7 @@ Future <- function(expr = NULL, envir = parent.frame(), substitute = TRUE, stdou
 
     gp <- NULL
   }
-  packages <- unique(packages)
+  if (length(packages) > 1L) packages <- unique(packages)
 
   with_assert({
     if (!is.null(globals)) {
@@ -710,7 +710,7 @@ getFutureCapture <- function(future, ..., debug = isTRUE(getOption("future.debug
       exclude <- attr(conditionClasses, "exclude", exact = TRUE)
       muffleInclude <- attr(conditionClasses, "muffleInclude", exact = TRUE)
       if (is.null(muffleInclude)) muffleInclude <- "^muffle"
-      conditionClasses <- unique(c(conditionClasses, immediateConditionClasses))
+      conditionClasses <- c(conditionClasses, immediateConditionClasses)
       attr(conditionClasses, "exclude") <- exclude
       attr(conditionClasses, "muffleInclude") <- muffleInclude
     }
@@ -750,10 +750,12 @@ getFutureContext <- function(future, mc.cores = NULL, local = TRUE, ..., debug =
     ## Identify package namespaces needed for strategies
     backendPackages <- lapply(strategiesR, FUN = environment)
     backendPackages <- lapply(backendPackages, FUN = environmentName)
-    backendPackages <- unique(unlist(backendPackages, use.names = FALSE))
-    ## CLEANUP: Only keep those that are loaded in the current session
-    backendPackages <- intersect(backendPackages, loadedNamespaces())
-    backendPackages <- unique(backendPackages)
+    backendPackages <- unlist(backendPackages, use.names = FALSE)
+    if (length(backendPackages) > 1L) backendPackages <- unique(backendPackages)
+    if (length(backendPackages) > 0L) {
+      ## CLEANUP: Only keep those that are loaded in the current session
+      backendPackages <- intersect(backendPackages, loadedNamespaces())
+    }
     if (debug) mdebugf("Packages needed by future strategies (n = %d): %s", length(backendPackages), commaq(backendPackages))
   }