Add assertion of internal 'batch.id' with information error message

Author: HenrikBengtsson

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future.batchtools
-Version: 0.20.0-9012
+Version: 0.20.0-9013
 Depends:
     R (>= 3.2.0),
     parallelly,

R/BatchtoolsFutureBackend-class.R

@@ -540,6 +540,12 @@ status <- function(future, ...) {
 
   ## Optionally filter by the scheduler's job ID, if it exists
   batch_id <- reg[["status"]][["batch.id"]]
+  if (!is.null(batch_id)) {
+    if (!is.character(batch_id) || length(batch_id) != 1L || is.na(batch_id) || !nzchar(batch_id) || !grepl("^[[:digit:].]+$", batch_id)) {
+      stop(sprintf("Unknown value of 'batch.id': [class=%d] %s", class(batch_id)[1], paste(sQuote(batch_id), collapse = ", ")))
+    }
+  }
+  
   ## Pass this to cluster functions listJobsQueued() and listJobsRunning()
   ## via an R option, because we cannot pass as an argument.
   options(