I'm not sure if this is accidental but get_contents_entry() and get_contents_dir() are returning strs (line 209, 219):

I ran into this when trying to debug this SConstruct,

v = Value('x')
e = Entry('something')
v.add_dependency([e])

v.get_contents()

which was producing the output,

AttributeError: 'str' object has no attribute 'decode':
  File ".../SConstruct", line 5:
    v.get_contents()
  File ".../SCons/Node/Python.py", line 155:
    text_contents = self.get_text_contents()
  File ".../SCons/Node/Python.py", line 147:
    contents = contents + kid.get_contents().decode()

I think this is because Value.get_text_contents() is expecting kid.get_contents() to be of type bytes.