Cython AttributeError: 'module' object has no attribute 'declare'

Question

Compiling .pyx files was working fine but suddenly it started raising error when I type:

python setup.py build_ext --inplace

I get the error:

c:\Python27\cython\helloworld>python setup.py build_ext --inplace
running build_ext
cythoning hello.pyx to hello.c
Traceback (most recent call last):
  File "setup.py", line 8, in <module>
    ext_modules = [Extension("hello", ["hello.pyx"])]
  File "C:\Python27\lib\distutils\core.py", line 152, in setup
    dist.run_commands()
  File "C:\Python27\lib\distutils\dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "C:\Python27\lib\distutils\dist.py", line 972, in run_command
    cmd_obj.run()
  File "C:\Python27\lib\site-packages\Cython\Distutils\build_ext.py", line 163,
in run
    _build_ext.build_ext.run(self)
  File "C:\Python27\lib\distutils\command\build_ext.py", line 340, in run
    self.build_extensions()
  File "C:\Python27\lib\site-packages\Cython\Distutils\build_ext.py", line 170,
in build_extensions
    ext.sources = self.cython_sources(ext.sources, ext)
  File "C:\Python27\lib\site-packages\Cython\Distutils\build_ext.py", line 317,
in cython_sources
    full_module_name=module_name)
  File "C:\Python27\lib\site-packages\Cython\Compiler\Main.py", line 605, in com
pile
    return compile_single(source, options, full_module_name)
  File "C:\Python27\lib\site-packages\Cython\Compiler\Main.py", line 546, in com
pile_single
    return run_pipeline(source, options, full_module_name)
  File "C:\Python27\lib\site-packages\Cython\Compiler\Main.py", line 386, in run
_pipeline
    import Pipeline
  File "C:\Python27\lib\site-packages\Cython\Compiler\Pipeline.py", line 7, in <
module>
    from Visitor import CythonTransform
  File "Visitor.py", line 9, in init Cython.Compiler.Visitor (Cython\Compiler\Vi
sitor.c:12838)
  File "C:\Python27\lib\site-packages\Cython\Compiler\Nodes.py", line 6, in <mod
ule>
    cython.declare(sys=object, os=object, copy=object,
AttributeError: 'module' object has no attribute 'declare'

I tried running it on a simple .pyx file helloworld:

def say_hello_to(name):
    print "Hello %s!" %name

with the setup.py:

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(
  name = 'Hello world app',
  cmdclass = {'build_ext': build_ext},
  ext_modules = [Extension("hello", ["hello.pyx"])]
)

It already worked several times, something has changed but as I Googled and searched the issue I couldn't find any information. I'm using Python 2.7 64 bits, latest version of Cython and to compile the file I use Windows SDK C/C++ compiler and prepare the environment by running:

C:\Program Files\Microsoft SDKs\Windows\v7.0>set DISTUTILS_USE_SDK=1
C:\Program Files\Microsoft SDKs\Windows\v7.0>setenv /x64 /release

Any ideas of what might have happened? Tnx in advance!

Might be useful to understand what imports do: stackoverflow.com/questions/13093665/… — NullUserException
– NullUserException, Commented Nov 14, 2012 at 17:11
Tnx for that, I'll research and see if I can find something! — Willian Fuks
– Willian Fuks, Commented Nov 14, 2012 at 18:15

Mads M Pedersen · Accepted Answer · 2013-02-28 07:43:25Z

7

I got the same error when running from a python script:

os.system("python setup.py build_ext --inplace")

while

python setup.py build_ext --inplace

worked from command promt.

The reason was that the name of my test package was "cython"... stupid me

answered Feb 28, 2013 at 7:43

Mads M Pedersen

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Comments

Robert · Accepted Answer · 2013-02-21 12:05:36Z

2

I have had the same error. Worked on it for one whole day until I have realized that I have followed some blog entry to create a cython.py file in my directory holding some information how to compile. I do not recall where I found this but by removing this file everything works fine

answered Feb 21, 2013 at 12:05

Robert

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yoavram · Accepted Answer · 2012-11-21 22:47:44Z

0

I'm not sure this helps, but when I got this error I deleted all .pyc files and ran the script again via IDLE (opened in IDLE and clicked F5) and then it worked just fine.

answered Nov 21, 2012 at 22:47

yoavram

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Max · Accepted Answer · 2023-04-28 11:52:18Z

0

This is an old post, but also one that still tops search results, so... for anyone stumbling on this - just doing pip uninstall Cython && pip install Cython worked for me.

answered Apr 28, 2023 at 11:52

Max

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