double-check for grouped_df in group_vars_

R/compat.R

@@ -9,12 +9,17 @@
 # dplyr -------------------------------------------------------------------
 #' Wrapper around dplyr::group_vars()
 #' @noRd
-group_vars_ = function(x) {
+group_vars_ = function(x, call = caller_env()) {
   if (requireNamespace("dplyr", quietly = TRUE)) {
     dplyr::group_vars(x)
   } else {
     # can't have grouped data frames without dplyr, so if dplyr isn't installed
-    # assume we aren't getting grouped dfs
+    # we most likely aren't getting grouped dfs --- but still double-check and
+    # fail in the most common case, grouped_df (maybe someone loaded an rds of a
+    # grouped df into a setup without dplyr or something...)
+    if (inherits(x, "grouped_df")) {
+      stop_not_installed("dplyr", context = "Using grouped data frames", call = call)
+    }
     character()
   }
 }

R/util.R

@@ -23,23 +23,27 @@ warning0 = function(...) {
 #' @param context beginning of error message giving the context (e.g. a
 #' package name and/or argument combination) that requires the package.
 #' @param ... additional messages placed into the `cli_abort()` message.
+#' @importFrom rlang caller_env
 #' @noRd
 stop_if_not_installed = function(packages, context = "This functionality", ..., call = caller_env()) {
   for (package in packages) {
     if (!requireNamespace(package, quietly = TRUE)) {
-      cli_abort(
-        c(
-          paste0(context, ' requires the {.pkg {package}} package.'),
-          ">" = 'Install the {.pkg {package}} package with {.run install.packages("{package}")}',
-          ...
-        ),
-        class = "ggdist_missing_package",
-        ggdist_package = package,
-        call = call
-      )
+      stop_not_installed(package, context = context, ..., call = call)
     }
   }
 }
+stop_not_installed = function(package, context = "This functionality", ..., call = caller_env()) {
+  cli_abort(
+    c(
+      paste0(context, ' requires the {.pkg {package}} package.'),
+      ">" = 'Install the {.pkg {package}} package with {.run install.packages("{package}")}',
+      ...
+    ),
+    class = "ggdist_missing_package",
+    ggdist_package = package,
+    call = call
+  )
+}
 
 # get all variable names from an expression
 # based on http://adv-r.had.co.nz/dsl.html