prompt on parameter extraction when implementation is missing

Author: simonpcouch

R/extract.R

@@ -74,6 +74,24 @@ extract_fit_engine.model_fit <- function(x, ...) {
 #' @export
 #' @rdname extract-parsnip
 extract_parameter_set_dials.model_spec <- function(x, ...) {
+  if (!spec_is_loaded(
+    cls = class(x)[1],
+    engine = x$engine,
+    user_specified_engine = x$user_specified_engine,
+    mode = x$mode,
+    user_specified_mode = x$user_specified_mode
+  )) {
+    prompt_missing_implementation(
+      cls = class(x)[1],
+      engine = x$engine,
+      user_specified_engine = x$user_specified_engine,
+      mode = x$mode,
+      user_specified_mode = x$user_specified_mode,
+      prompt = cli::cli_abort,
+      call = NULL
+    )
+  }
+
   all_args <- generics::tunable(x)
   tuning_param <- generics::tune_args(x)
 

tests/testthat/_snaps/extract.md

@@ -0,0 +1,20 @@
+# extract parameter set from model with no loaded implementation
+
+    Code
+      extract_parameter_set_dials(bt_mod)
+    Condition
+      Error:
+      ! parsnip could not locate an implementation for `bag_tree` regression model specifications.
+      i The parsnip extension package baguette implements support for this specification.
+      i Please install (if needed) and load to continue.
+
+---
+
+    Code
+      extract_parameter_dials(bt_mod, parameter = "min_n")
+    Condition
+      Error:
+      ! parsnip could not locate an implementation for `bag_tree` regression model specifications.
+      i The parsnip extension package baguette implements support for this specification.
+      i Please install (if needed) and load to continue.
+

tests/testthat/test_extract.R

@@ -50,6 +50,14 @@ test_that('extract parameter set from model with main and engine parameters', {
   expect_equal(c5_info$object[[2]], NA)
 })
 
+test_that('extract parameter set from model with no loaded implementation', {
+  bt_mod <- bag_tree(min_n = tune()) %>%
+    set_mode("regression")
+
+  expect_snapshot(error = TRUE, extract_parameter_set_dials(bt_mod))
+  expect_snapshot(error = TRUE, extract_parameter_dials(bt_mod, parameter = "min_n"))
+})
+
 # ------------------------------------------------------------------------------
 
 test_that('extract single parameter from model with no parameters', {