Model: Raise an exception if transformation results in all nans

Orange/base.py

@@ -9,6 +9,7 @@
 
 from Orange.data import Table, Storage, Instance, Value
 from Orange.data.filter import HasClass
+from Orange.data.table import DomainTransformationError
 from Orange.data.util import one_hot
 from Orange.misc.wrapper_meta import WrapperMeta
 from Orange.preprocess import Continuize, RemoveNaNColumns, SklImpute, Normalize
@@ -246,7 +247,14 @@ def __call__(self, data, ret=Value):
             if isinstance(data, Instance):
                 data = Table(data.domain, [data])
             if data.domain != self.domain:
+                orig = data
                 data = data.transform(self.domain)
+                if data.X.size \
+                        and np.isnan(data.X).all() \
+                        and not np.isnan(orig.X).all() \
+                        and data.domain.attributes != orig.domain.attributes:
+                    raise DomainTransformationError(
+                        "domain transformation produced no defined values")
             prediction = self.predict_storage(data)
         elif isinstance(data, (list, tuple)):
             if not isinstance(data[0], (list, tuple)):

Orange/data/table.py

@@ -44,6 +44,10 @@ def get_sample_datasets_dir():
 _conversion_cache_lock = RLock()
 
 
+class DomainTransformationError(Exception):
+    pass
+
+
 class RowInstance(Instance):
     sparse_x = None
     sparse_y = None