load_libs() with engine == "kknn" and factor predictors (#914)

Author: simonpcouch

NEWS.md

@@ -4,6 +4,8 @@
 
 * Made `fit()` behave consistently with respect to missingness in the classification setting. Previously, `fit()` erroneously raised an error about the class of the outcome when there were no complete cases, and now always passes along complete cases to be handled by the modeling function (#888).
 
+* Fixed bug where model fits with factor predictors and `engine = "kknn"` would fail when the package's namespace hadn't been attached (#264).
+
 * `.organize_glmnet_pred()` now expects predictions for a single penalty value (#876).
 
 * Fixed bug where model fits with `engine = "earth"` would fail when the package's namespace hadn't been attached (#251).

R/nearest_neighbor.R

@@ -120,6 +120,7 @@ translate.nearest_neighbor <- function(x, engine = x$engine, ...) {
   arg_vals <- x$method$fit$args
 
   if (engine == "kknn") {
+    load_libs(x, quiet = TRUE, attach = TRUE)
 
     if (!any(names(arg_vals) == "ks") || is_missing_arg(arg_vals$ks)) {
       arg_vals$ks <- 5