updating get_choices function. (#282)

extension to insightsengineering/teal.osprey#276

---------

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Dawid Kałędkowski <6959016+gogonzo@users.noreply.github.com>

DESCRIPTION

@@ -77,4 +77,4 @@ Encoding: UTF-8
 Language: en-US
 LazyData: true
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.3.1
+RoxygenNote: 7.3.2

R/utils.R

@@ -87,14 +87,27 @@ report_card_template_goshawk <- function(title,
 #'
 #' This function returns choices based on the class of the input.
 #' If the input is of class `delayed_data`, it returns the `subset` of the input.
+#' If `subset` is NULL and the input contains `var_label` and `var_choices`,
+#' it throws an error prompting to resolve delayed inputs.
 #' Otherwise, it returns the input as is.
 #'
 #' @param choices An object that contains choices.
 #' @return A vector of choices.
 #' @keywords internal
 get_choices <- function(choices) {
   if (inherits(choices, "delayed_data")) {
-    choices$subset
+    if (is.null(choices$subset)) {
+      if (!is.null(choices$var_label) && !is.null(choices$var_choices)) {
+        stop(
+          "Resolve delayed inputs by evaluating the code within the provided datasets.
+          Check ?teal.transform::resolve_delayed for more information."
+        )
+      } else {
+        stop("Subset is NULL and necessary fields are missing.")
+      }
+    } else {
+      choices$subset
+    }
   } else {
     choices
   }