Fixes MultipleSelectInterface

It doesn't derive from IdentityInterface anymore (caused node removal
in workflows).

Also applied improved dynamictraited interfaces checking in workflows.

Author: oesteban

nipype/interfaces/utility.py

@@ -557,7 +557,7 @@ class MultipleSelectInputSpec(DynamicTraitedSpec):
     index = InputMultiPath(traits.Int, mandatory=True,
                            desc='0-based indices of values to choose')
 
-class MultipleSelectInterface(IdentityInterface):
+class MultipleSelectInterface(IOBase):
     """
     Basic interface that demultiplexes lists generated by CollateInterface
 
@@ -578,7 +578,7 @@ class MultipleSelectInterface(IdentityInterface):
     output_spec = DynamicTraitedSpec
 
     def __init__(self, fields=None, mandatory_inputs=True, **inputs):
-        super(IdentityInterface, self).__init__(**inputs)
+        super(MultipleSelectInterface, self).__init__(**inputs)
         if fields is None or not fields:
             raise ValueError('Identity Interface fields must be a non-empty list')
         # Each input must be in the fields.
@@ -593,6 +593,14 @@ def __init__(self, fields=None, mandatory_inputs=True, **inputs):
         # the values after adding the traits.
         self.inputs.set(**inputs)
 
+    def _add_output_traits(self, base):
+        undefined_traits = {}
+        for key in self._fields:
+            base.add_trait(key, traits.Any)
+            undefined_traits[key] = Undefined
+        base.trait_set(trait_change_notify=False, **undefined_traits)
+        return base
+
     def _list_outputs(self):
         #manual mandatory inputs check
         if self._fields and self._mandatory_inputs:

nipype/pipeline/engine.py

@@ -190,7 +190,7 @@ def _check_outputs(self, parameter):
         return hasattr(self.outputs, parameter)
 
     def _check_inputs(self, parameter):
-        if hasattr(self.inputs,'_outputs'):
+        if isinstance(self.inputs, DynamicTraitedSpec):
             return True
         return hasattr(self.inputs, parameter)