load_libs() with engine == "earth" (#913)

Author: simonpcouch

NEWS.md

@@ -6,6 +6,8 @@
 
 * `.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).
+
 * Fixed bug with prediction from a boosted tree model fitted with `"xgboost"` using a custom objective function (#875).
 
 * Several internal functions (to help work with `Surv` objects) were added as a standalone file that can be used in other packages via `usethis::use_standalone("tidymodels/parsnip")`. 

R/mars.R

@@ -86,6 +86,9 @@ translate.mars <- function(x, engine = x$engine, ...) {
     message("Used `engine = 'earth'` for translation.")
     engine <- "earth"
   }
+  if (engine == "earth") {
+    load_libs(x, quiet = TRUE, attach = TRUE)
+  }
   # If classification is being done, the `glm` options should be used. Check to
   # see if it is there and, if not, add the default value.
   if (x$mode == "classification") {