fix(bundle): always (un)bundle for callr encapsulation

R/worker.R

@@ -18,6 +18,10 @@ learner_train = function(learner, task, train_row_ids = NULL, test_row_ids = NUL
       stopf("Learner '%s' on task '%s' returned NULL during internal %s()", learner$id, task$id, mode)
     }
 
+    if ("bundle" %in% learner$properties && identical(learner$encapsulate[["train"]], "callr")) {
+      model = get_private(learner)$.bundle(model)
+    }
+
     model
   }
 
@@ -68,11 +72,16 @@ learner_train = function(learner, task, train_row_ids = NULL, test_row_ids = NUL
   log = append_log(NULL, "train", result$log$class, result$log$msg)
   train_time = result$elapsed
 
+  # callr encapsualtion causes dangling pointers between train and predict
+  bundled = if ("bundle" %in% learner$properties) {
+    identical(learner$encapsulate[["train"]], "callr")
+  }
+
   learner$state = insert_named(learner$state, list(
     model = result$result,
     log = log,
     train_time = train_time,
-    bundled = if ("bundle" %in% learner$properties) FALSE else NULL,
+    bundled = bundled,
     param_vals = learner$param_set$values,
     task_hash = task$hash,
     feature_names = task$feature_names,
@@ -102,6 +111,10 @@ learner_train = function(learner, task, train_row_ids = NULL, test_row_ids = NUL
       fb$id, learner = fb$clone())
   }
 
+  if (isTRUE(bundled)) {
+    learner$unbundle()
+  }
+
   learner
 }
 

tests/testthat/test_Learner.R

@@ -329,6 +329,12 @@ test_that("bundling", {
   task = tsk("mtcars")
   LearnerRegrTest = R6Class("LearnerRegrTest",
     inherit = LearnerRegrFeatureless,
+    public = list(
+      initialize = function() {
+        super$initialize()
+        self$id = "regr.test"
+      }
+    ),
     private = list(
       .bundle = function(model) {
         private$.tmp_model = model
@@ -337,9 +343,11 @@ test_that("bundling", {
       .unbundle = function(model) {
         model = private$.tmp_model
         private$.tmp_model = NULL
+        private$.counter = private$.counter + 1
         model
       },
-      .tmp_model = NULL
+      .tmp_model = NULL,
+      .counter = 0
     )
   )
 
@@ -384,4 +392,20 @@ test_that("bundling", {
   # calling (un)bundle does nothing
   expect_true(is.null(lrn_rpart$bundle()$bundled))
   expect_true(is.null(lrn_rpart$unbundle()$bundled))
+
+  # callr encapsulation causes bundling
+  learner2 = LearnerRegrTest$new()
+  learner2$encapsulate = c(train = "callr")
+  learner2$train(task)
+  expect_false(learner2$bundled)
+
+  learner3 = LearnerRegrTest$new()
+  learner3$encapsulate = c(train = "try")
+  learner3$train(task)
+  expect_false(learner3$bundled)
+
+  # for callr, we had to unbundle
+  expect_equal(get_private(learner2)$.counter, 1)
+  # for other encapsulation, no need to unbundle becausse it was not bundled
+  expect_equal(get_private(learner3)$.counter, 0)
 })