bug in setting __module__

[robertwb]

Hi folks,

I'm wondering if this is expected behavior.  Consider some trivial
little class like

class Simpleton:
   def __str__(self):
       return "A simpleton"

   def incr(self,x):
       """Increment x by one.

       Examples:

s = Simpleton()
s.incr(1)
       2
s.incr(10)
       12
       """
       return x+1

If I build this thing in cython, the Simpleton.incr.__module__
attribute is set to None, while if I make it a pure python module,
it's correctly set to the module name:


In [p sprimes.primes.Simpleton.incr.__module__
None

In [19](18]:): p sprimes.pyprimes.Simpleton.incr.__module__
sprimes.pyprimes

This difference causes the doctest to miss any doctest examples that
might be included in the methods.

Note that for *top-level* functions in the extension module, the
__module__ attribute is correctly set:

In [p sprimes.primes.primes
<built-in function primes>

In [22](21]:): p sprimes.primes.primes.__module__
sprimes.primes

so the problem appears to be only for classes.

This is running cython 0.9.8.

Thanks for any feedback,

f

At 2010-05-17T10:33:38Z @bhy added attachment fix_T422.patch

Migrated from http://trac.cython.org/ticket/422

[robertwb]

@bhy commented

This is due to PyFunction_New creates the PyFunction with the module set as NULL. We should call PyFunction_NewEx, which accepts a PyObject as module name.

[robertwb]

@bhy changed cc to biahaoyu@gmail.com
commented

[robertwb]

@robertwb commented

It may be worth creating the PyObject? module name at module load time (do we do that already), and simply re-using that, rather than re-creating it for every function.

Binding functions need to be changed as well.

[robertwb]

@bhy changed owner from somebody to haoyu
commented

Patch for review:
http://codereview.appspot.com/1228043/

[robertwb]

@bhy changed resolution to fixed
status from new to closed
commented

[graingert]

I seem to still see this in cython 0.29.32 (it's fixed in Cython-3.0.0a11)

[graingert]

ah this only applies to cdef classes eg:

import cython

@cython.cclass
class Function:
    @cython.ccall
    def evaluate(self, x: float) -> float:
        return 0

I get the __module__ attribute in v3a11:

Python 3.10.4 (main, Jun 29 2022, 12:14:53) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pyximport
>>> pyximport.install(reload_support=True)
(None, <pyximport._pyximport3.PyxImportMetaFinder object at 0x7efd8a6ef970>)
/home/graingert/.virtualenvs/testing310/lib/python3.10/site-packages/Cython/Compiler/Main.py:345: FutureWarning: Cython directive 'language_level' not set, using '3str' for now (Py3). This has changed from earlier releases! File: /home/graingert/projects/uvloop/foo.pyx
  tree = Parsing.p_module(s, pxd, full_module_name)
>>> foo.Function().evaluate
<bound method Function.evaluate of <foo.Function object at 0x7efd8a59d990>>
>>> foo.Function().evaluate.__module__
'foo'

but not in 0.29.32:

Python 3.10.4 (main, Jun 29 2022, 12:14:53) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pyximport
>>> pyximport.install(reload_support=True)
(None, <pyximport.pyximport.PyxImporter object at 0x7f1e52ecb970>)
>>> import foo
/home/graingert/.virtualenvs/testing310/lib/python3.10/site-packages/Cython/Compiler/Main.py:369: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: /home/graingert/projects/uvloop/foo.pyx
  tree = Parsing.p_module(s, pxd, full_module_name)
>>> foo.Function()
<foo.Function object at 0x7f1e52a68870>
>>> foo.Function().evaluate
<built-in method evaluate of foo.Function object at 0x7f1e50f429f0>
>>> foo.Function().evaluate.__module__

[graingert]

ah it's the compiler directive http://docs.cython.org/en/latest/src/userguide/source_files_and_compilation.html#compiler-directives #1750 (comment)