fix issue with new R-devel

DESCRIPTION

@@ -2,8 +2,8 @@ Package: brms
 Encoding: UTF-8
 Type: Package
 Title: Bayesian Regression Models using 'Stan'
-Version: 2.20.3
-Date: 2023-09-14
+Version: 2.20.4
+Date: 2023-09-25
 Authors@R:
     c(person("Paul-Christian", "Bürkner", email = "paul.buerkner@gmail.com",
              role = c("aut", "cre")),

R/conditional_effects.R

@@ -519,7 +519,7 @@ get_all_effects.mvbrmsterms <- function(x, ...) {
 #   excludes all 3-way or higher interactions
 #' @export
 get_all_effects.brmsterms <- function(x, rsv_vars = NULL, comb_all = FALSE, ...) {
-  stopifnot(is.atomic(rsv_vars))
+  stopifnot(is_atomic_or_null(rsv_vars))
   out <- list()
   for (dp in names(x$dpars)) {
     out <- c(out, get_all_effects(x$dpars[[dp]]))

R/data-predictor.R

@@ -976,7 +976,7 @@ data_special_prior <- function(bterms, data, prior, ranef, sdata = NULL) {
 #   For details see ?stats::model.matrix
 get_model_matrix <- function(formula, data = environment(formula),
                              cols2remove = NULL, rename = TRUE, ...) {
-  stopifnot(is.atomic(cols2remove))
+  stopifnot(is_atomic_or_null(cols2remove))
   terms <- validate_terms(formula)
   if (is.null(terms)) {
     return(NULL)

R/misc.R

@@ -241,6 +241,10 @@ first_not_null <- function(...) {
   out
 }
 
+is_atomic_or_null <- function(x) {
+  is.atomic(x) || is.null(x)
+}
+
 isNA <- function(x) {
   length(x) == 1L && is.na(x)
 }