chore: add hint that resampling could be instantiated on a different …

…task (#1200)
mlr-org · Nov 5, 2024 · ea53d4a · ea53d4a
1 parent 0c46b69
commit ea53d4a
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/R/Task.R b/R/Task.R
@@ -305,7 +305,8 @@ Task = R6Class("Task",
       data = self$backend$data(rows = rows, cols = query_cols)
 
       if (length(query_cols) && nrow(data) != length(rows)) {
-        stopf("DataBackend did not return the queried rows correctly: %i requested, %i received", length(rows), nrow(data))
+        stopf("DataBackend did not return the queried rows correctly: %i requested, %i received.
+        The resampling was probably instantiated on a different task.", length(rows), nrow(data))
       }
 
       if (length(rows) && ncol(data) != length(query_cols)) {

diff --git a/tests/testthat/test_resample.R b/tests/testthat/test_resample.R
@@ -512,3 +512,11 @@ test_that("predict_time is 0 if no predict_set is specified", {
   expect_true(all(times == 0))
 })
 
+test_that("resampling instantiated on a different task throws an error", {
+  task = tsk("spam")
+  resampling = rsmp("cv", folds = 3)
+  resampling$instantiate(task)
+
+  expect_error(resample(tsk("pima"), lrn("classif.rpart"), resampling), "The resampling was probably instantiated on a different task")
+
+})