TraitError: The 'file_name' trait of a PolyDataWriter instance must be a unicode string ...

[yarikoptic]

Summary

trying to update debian package for 1.0.1-97-g803982c21 . not yet sure if that is nohow specifics of my system (will try now in a clean chroot etc) with python-traits 4.6.0-1+b1. Note that issue subject reflects only one of the two failures

=================================== FAILURES ===================================
_____________________________ test_ident_distances _____________________________
[gw3] linux2 -- Python 2.7.14 /usr/bin/python

tmpdir = local('/tmp/pytest-of-yoh/pytest-0/popen-gw3/test_ident_distances0')

    @pytest.mark.skipif(VTKInfo.no_tvtk(), reason="tvtk is not installed")
    def test_ident_distances(tmpdir):
        tmpdir.chdir()
    
        in_surf = example_data('surf01.vtk')
        dist_ident = m.ComputeMeshWarp()
        dist_ident.inputs.surface1 = in_surf
        dist_ident.inputs.surface2 = in_surf
>       dist_ident.inputs.out_file = tmpdir.join('distance.npy')

/home/yoh/deb/gits/pkg-exppsy/build-area/nipype-1.0.1+git97-g803982c21/nipype/algorithms/tests/test_mesh_ops.py:24: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/home/yoh/deb/gits/pkg-exppsy/build-area/nipype-1.0.1+git97-g803982c21/nipype/interfaces/base/traits_extension.py:103: in validate
    validated_value = super(File, self).validate(object, name, value)
/usr/lib/python2.7/dist-packages/traits/trait_types.py:411: in validate
    self.error( object, name, value )
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <nipype.interfaces.base.traits_extension.File object at 0x7f2809ce4110>
object = 
ignore_exception = False
metric = euclidean
out_file = distance.npy
out_warp .../nipype-1.0.1+git97-g803982c21/nipype/testing/data/surf01.vtk
weighting = none

name = 'out_file'
value = local('/tmp/pytest-of-yoh/pytest-0/popen-gw3/test_ident_distances0/distance.npy')

    def error ( self, object, name, value ):
        """Raises a TraitError exception.
    
            Parameters
            ----------
            object : object
                The object whose attribute is being assigned.
            name : str
                The name of the attribute being assigned.
            value : object
                The proposed new value for the attribute.
    
            Description
            -----------
            This method is called by the validate() method when an assigned value
            is not valid. Raising a TraitError exception either notifies the user of
            the problem, or, in the case of compound traits, provides a chance for
            another trait handler to handle to validate the value.
            """
        raise TraitError( object, name, self.full_info( object, name, value ),
>                         value )
E       TraitError: The 'out_file' trait of a ComputeMeshWarpInputSpec instance must be a file name, but a value of local('/tmp/pytest-of-yoh/pytest-0/popen-gw3/test_ident_distances0/distance.npy') <class 'py._path.local.LocalPath'> was specified.

/usr/lib/python2.7/dist-packages/traits/trait_handlers.py:172: TraitError
_____________________________ test_trans_distances _____________________________
[gw1] linux2 -- Python 2.7.14 /usr/bin/python

tmpdir = local('/tmp/pytest-of-yoh/pytest-0/popen-gw1/test_trans_distances0')

    @pytest.mark.skipif(VTKInfo.no_tvtk(), reason="tvtk is not installed")
    def test_trans_distances(tmpdir):
        from ...interfaces.vtkbase import tvtk
    
        in_surf = example_data('surf01.vtk')
        warped_surf = tmpdir.join('warped.vtk')
    
        inc = np.array([0.7, 0.3, -0.2])
    
        r1 = tvtk.PolyDataReader(file_name=in_surf)
        vtk1 = VTKInfo.vtk_output(r1)
        r1.update()
        vtk1.points = np.array(vtk1.points) + inc
    
>       writer = tvtk.PolyDataWriter(file_name=warped_surf)

/home/yoh/deb/gits/pkg-exppsy/build-area/nipype-1.0.1+git97-g803982c21/nipype/algorithms/tests/test_mesh_ops.py:47: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/usr/lib/python2.7/dist-packages/tvtk/tvtk_classes.zip/tvtk_classes/poly_data_writer.py:46: in __init__
    tvtk_base.TVTKBase.__init__(self, vtk.vtkPolyDataWriter, obj, update, **traits)
/usr/lib/python2.7/dist-packages/tvtk/tvtk_base.py:336: in __init__
    super(TVTKBase, self).__init__(**traits)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <traits.trait_handlers.TraitCompound object at 0x7f32d813f890>
object = <tvtk.tvtk_classes.poly_data_writer.PolyDataWriter object at 0x7f32b66056b0>
name = 'file_name'
value = local('/tmp/pytest-of-yoh/pytest-0/popen-gw1/test_trans_distances0/warped.vtk')

    def error ( self, object, name, value ):
        """Raises a TraitError exception.
    
            Parameters
            ----------
            object : object
                The object whose attribute is being assigned.
            name : str
                The name of the attribute being assigned.
            value : object
                The proposed new value for the attribute.
    
            Description
            -----------
            This method is called by the validate() method when an assigned value
            is not valid. Raising a TraitError exception either notifies the user of
            the problem, or, in the case of compound traits, provides a chance for
            another trait handler to handle to validate the value.
            """
        raise TraitError( object, name, self.full_info( object, name, value ),
>                         value )
E       TraitError: The 'file_name' trait of a PolyDataWriter instance must be a unicode string or a value of type 'str' or None, but a value of local('/tmp/pytest-of-yoh/pytest-0/popen-gw1/test_trans_distances0/warped.vtk') <class 'py._path.local.LocalPath'> was specified.

/usr/lib/python2.7/dist-packages/traits/trait_handlers.py:172: TraitError

[djarecka]

we have traits >= 4.6, so would be good to see if this error still exists with 4.6

[effigies]

Ah, looks like this is a py.path issue. Can you change:

- writer = tvtk.PolyDataWriter(file_name=warped_surf)
+ writer = tvtk.PolyDataWriter(file_name=warped_surf.strpath)

A similar fix should apply for the other case, as well. It looks like we're not testing with tvtk on CircleCI...

[effigies]

OTOH, it might be useful if future versions allow File traits to accept py.path and pathlib objects. There's been some relevant discussion in nipy/nibabel#610.