AttributeError: class Extension has no attribute '__mro__'

[vivekvenkris]

Hey Michele,

I am trying to install libstempo but get different errors on different platforms. This is the OSX error that I get:

WARNING: The libstempo API has changed substantially (for the better) from
versions 1.X to 2.X. If you need the older 1.X API, you can get an older libstempo
from https://pypi.python.org/simple/libstempo, or checkout the libstempo1
branch on GitHub - https://github.com/vallis/libstempo/tree/libstempo1
Found tempo2 install in [u'/Users/vkrishnan/T2runtime/'], will use it.
Traceback (most recent call last):
File "setup.py", line 109, in
extra_link_args = linkArgs))
File "/Users/vkrishnan/anaconda/lib/python2.7/site-packages/Cython/Build/Dependencies.py", line 818, in cythonize
aliases=aliases)
File "/Users/vkrishnan/anaconda/lib/python2.7/site-packages/Cython/Build/Dependencies.py", line 648, in create_extension_list
elif isinstance(patterns, basestring) or not isinstance(patterns, collections.Iterable):
File "/Users/vkrishnan/anaconda/lib/python2.7/abc.py", line 144, in instancecheck
return cls.subclasscheck(subtype)
File "/Users/vkrishnan/anaconda/lib/python2.7/abc.py", line 180, in subclasscheck
if issubclass(subclass, scls):
File "/Users/vkrishnan/anaconda/lib/python2.7/abc.py", line 180, in subclasscheck
if issubclass(subclass, scls):
File "/Users/vkrishnan/anaconda/lib/python2.7/abc.py", line 161, in subclasscheck
ok = cls.subclasshook(subclass)
File "/Users/vkrishnan/anaconda/lib/python2.7/site-packages/backports_abc.py", line 66, in subclasshook
mro = C.mro
AttributeError: class Extension has no attribute 'mro'

I tried pip install and setup.puy but both give the same error. Can you please tell me how to fix it?

My softwares:
conda 4.3.25
Python 2.7.11 :: Anaconda custom (x86_64)
OSX El Capitan 10.11.6
gcc (GCC) 4.9.2 20141029
g++ (GCC) 4.9.2 20141029
Tempo2 2017.03.1

Thanks,
Vivek

[vivekvenkris]

Some googling suggested it is a conflict with cython and setuptools which should have been resolved in the versions I am using but doesn't seem like it.

My versions:
setuptools: 36.4.0-py27_1
cython: 0.26-py27_0

[vivekvenkris]

Okay, Changing

backports_abc: 0.4-py27_0 --> 0.5-py27_0
tornado: 4.3-py27_0 --> 4.5.2-py27_0

seems to have done the trick. Sorry for posting the issue too soon! May be this will help others at some point. Please close this issue.

Vivek

[jellis18]

@vivekvenkris, I actually just had this problem as well and moving to Cython 0.25 from Cython 0.26 worked as well. Maybe this was done internally when you downgraded tornado?

Either, way @vallis and I should make take a look at this so it will fork for newer Cython versions.