@staticmethod with implicit object argument type is handled wrongly

[navytux]

Hello up there. Please consider the following example:

---- 8< ---- moda.pxd

cdef class MyClass:
    @staticmethod
    cdef static_func(x)

---- 8< ---- moda.pyx

cdef class MyClass:
    @staticmethod
    cdef static_func(x):
        return x+1

---- 8< ---- modb.pyx

from moda cimport MyClass

def test():
    x = MyClass.static_func(2)
    print(x)

When compiled and run it fails with:

$ python -c 'import modb; modb.test()'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "modb.pyx", line 4, in modb.test
    x = MyClass.static_func(2)
TypeError: Cannot convert int to moda.MyClass

If I add explicit object to x argument in moda.pxd:

--- a/moda.pxd
+++ b/moda.pxd
@@ -1,3 +1,3 @@
 cdef class MyClass:
     @staticmethod
-    cdef static_func(x)
+    cdef static_func(object x)

It works:

$ python -c 'import modb; modb.test()'
3

Thanks beforehand,
Kirill

/cc @robertwb

[navytux]

I forgot to mention that it fails for both current 0.29.x and master.
I added corresponding test in #3175.

[scoder]

My guess is that it fails because @staticmethod is not evaluated (correctly) in .pxd files. Or maybe it incorrectly overwrites the prior handling of the decorator in the implementation file somehow.

PR for that is welcome, but I can't say what needs to be done for that. Needs some analysis to find out where this should be fixed.

[navytux]

@scoder, thanks for feedback. My impression is that somehow the "pass" that automatically annotates first argument of a method of a cdef class with corresponding type overwrites @staticmethod effect somehow. But I did not looked into the code at all. For now I filed PR with test (#3175, it can be already merged), this issue, so that the bug is not forgotten, and in my codebase worked around the problem with explicitly using object type for the first argument.

[jankulovski]

Same issue reproduced. Any updates on this?

[navytux]

Thanks