added type checking

theano/gof/fg.py

@@ -617,6 +617,11 @@ class FunctionGraph(utils.object2):
                     raise TypeError("Non-deterministic return value from " \
                             +str(feature.orderings) \
                             +". Nondeterministic object is "+str(orderings))
+                for node, prereqs in orderings.items():
+                    if not isinstance(prereqs, (list, OrderedSet)):
+                        raise TypeError("prereqs must be a type with a "
+                                "deterministic iteration order, or toposort "
+                                " will be non-deterministic.")
                     ords.setdefault(node, []).extend(prereqs)
         # eliminate duplicate prereqs
         for (node,prereqs) in ords.items():

theano/gof/graph.py

@@ -15,6 +15,7 @@ import theano
 import warnings
 from theano.gof import utils
 from theano.gof.python25 import any, deque
+from theano.misc.ordered_set import OrderedSet
 
 # Lazy imports to avoid circular dependencies.
 is_same_graph_with_merge = None