Stack: new table instead of transform

Orange/ensembles/stack.py

@@ -81,7 +81,7 @@ def fit_storage(self, data):
         dom = Domain([ContinuousVariable('f{}'.format(i + 1))
                       for i in range(X.shape[1])],
                      data.domain.class_var)
-        stacked_data = data.transform(dom).copy()
+        stacked_data = Table.from_table(dom, data)
         with stacked_data.unlocked_reference():
             stacked_data.X = X
             stacked_data.Y = res.actual

Orange/tests/test_stack.py

@@ -1,7 +1,7 @@
 import unittest
 
 from Orange.data import Table
-from Orange.ensembles.stack import StackedFitter
+from Orange.ensembles.stack import StackedFitter, StackedLearner
 from Orange.evaluation import CA, CrossValidation, MSE
 from Orange.modelling import KNNLearner, TreeLearner
 
@@ -26,3 +26,16 @@ def test_regression(self):
         mse = MSE()(results)
         self.assertLess(mse[0], mse[1])
         self.assertLess(mse[0], mse[2])
+
+    def test_timeseries(self):
+        def aggregate(data):
+            assert type(data) is Table
+
+        class CustomTable(Table):
+            pass
+
+        sl = StackedLearner([TreeLearner(), KNNLearner()],
+                             aggregate=aggregate)
+
+        data = CustomTable(self.iris)
+        sl(data)