BUG FIX: value(..., reduce = structure("+", init = 42)) did not work

Author: HenrikBengtsson

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future
-Version: 1.67.0-9013
+Version: 1.67.0-9015
 Title: Unified Parallel and Distributed Processing in R for Everyone
 Depends:
     R (>= 3.2.0)

NEWS.md

@@ -26,6 +26,12 @@ repeat. This release fixes a few more regressions introduced in
    until the machine ran out of resources. This bug was introduced in
    **future** (>= 1.67.0) [2025-07-29].
 
+ * `value(..., reduce = structure(`+`, init = 42))` is not supported,
+   because `+` is a primitive function and one must not set attributes
+   on primitive functions. `value()` detects this and produces an
+   error suggestion to use `reduce = structure("+", init = 42)`
+   instead. The latter still gave the same error, which is now fixed.
+
 
 # Version 1.67.0 [2025-07-29]
 

R/core_api-value.R

@@ -470,27 +470,27 @@ value.list <- function(x, idxs = NULL, recursive = 0, reduce = NULL, stdout = TR
       reduce <- fcn
     } else if (is.function(reduce)) {
       stop_if_not(is.function(reduce))
-      if (!is.primitive(reduce)) {
+      if (is.primitive(reduce)) {
+        ## SPECIAL CASE: Protect against mistakes
+        ## See R-devel thread '[Rd] structure(<primitive function>, ...) is
+        ## sticky: a bug, or should it be an error?' on 2025-03-19
+        ## <https://stat.ethz.ch/pipermail/r-devel/2025-March/083892.html>
+        if (is.primitive(reduce) && !is.null(attr(reduce, "init", exact = TRUE))) {
+          ## FIXME?: At least in R 4.4.3, none of the primitive functions have
+          ## attributes. Because of that, we could do attributes(reduce) <- NULL
+          ## here before throwing the error. But is that a safe assumption?
+          name <- name_of_function(reduce)
+          nameq <- name
+          if (!grepl("^[[:alpha:]]", nameq)) nameq <- sprintf("`%s`", nameq)
+          stop(sprintf("You must not set an 'init' reduce value on 'base' function %s(), because it is a primitive function. You can use 'reduce = structure(\"%s\", init = <value>)' instead", nameq, name))
+        }
+      } else {
         args <- names(formals(reduce))
         if (length(args) == 0) {
           stop("The 'reduce' function must take at least one argument")
         }
       }
-    }
-    
-    ## SPECIAL CASE: Protect against mistakes
-    ## See R-devel thread '[Rd] structure(<primitive function>, ...) is
-    ## sticky: a bug, or should it be an error?' on 2025-03-19
-    ## <https://stat.ethz.ch/pipermail/r-devel/2025-March/083892.html>
-    if (is.primitive(reduce) && !is.null(attr(reduce, "init", exact = TRUE))) {
-      ## FIXME?: At least in R 4.4.3, none of the primitive functions have
-      ## attributes. Because of that, we could do attributes(reduce) <- NULL
-      ## here before throwing the error. But is that a safe assumption?
-      name <- name_of_function(reduce)
-      nameq <- name
-      if (!grepl("^[[:alpha:]]", nameq)) nameq <- sprintf("`%s`", nameq)
-      stop(sprintf("You must not set an 'init' reduce value on 'base' function %s(), because it is a primitive function. You can use 'reduce = structure(\"%s\", init = <value>)' instead", nameq, name))
-    }
+    }    
   } ## if (do_reduce)
 
   stop_if_not(

incl/value.R

@@ -25,9 +25,9 @@ vs <- unlist(vs)
 message("The ten averages are: ", paste(vs, collapse = ", "))
 
 ## The values as a vector (by reducing)
-vs <- value(fs, reduce = `c`)
+vs <- value(fs, reduce = c)
 message("The ten averages are: ", paste(vs, collapse = ", "))
 
 ## Calculate the sum of the averages (by reducing)
-total <- value(fs, reduce = `sum`)
+total <- value(fs, reduce = `+`)
 message("The sum of the ten averages is: ", total)