disable boost on errors steps for custom validation strategy (#380)

supervised/tuner/mljar_tuner.py

@@ -181,8 +181,14 @@ def steps(self):
             all_steps += ["features_selection"]
         for i in range(self._hill_climbing_steps):
             all_steps += [f"hill_climbing_{i+1}"]
-        if self._boost_on_errors and self._fairness_metric is None:
-            # we can tun boost on errors only if there is not fairness optimization
+        if (
+            self._boost_on_errors
+            and self._fairness_metric is None
+            and self._validation_strategy.get("validation_type", "") != "custom"
+        ):
+            # we can turn boost on errors only if there is not fairness optimization
+            # boost on errors will not work for custom validation strategy
+            # because we cant assure that we have all samples in out-of-folds predictions
             all_steps += ["boost_on_errors"]
         if self._train_ensemble:
             all_steps += ["ensemble"]

supervised/validation/validator_custom.py

@@ -88,7 +88,7 @@ def get_split(self, k, repeat=0):
             validation_data = {
                 "X": X.iloc[validation_index],
                 "y": y.iloc[validation_index],
-            }
+            }            
             if sample_weight is not None:
                 train_data["sample_weight"] = sample_weight.iloc[train_index]
                 validation_data["sample_weight"] = sample_weight.iloc[validation_index]