Hi, thanks for the very detailed report.
I'm CC-ing cython-devel, but let's keep the discussion for this on the cython-users list. The background here is Github issue 1382 and PR 3123 https://github.com/cython/cython/issues/1382 https://github.com/cython/cython/pull/3123 This was newly merged for alpha 2, and I consider it somewhat provisional. It makes "private" Python names follow Python semantics, but if that poses excessive breakage for existing code, then we'll have to find a pragmatic way to deal with it. 'Toni Barth' via cython-users schrieb am 23.04.20 um 19:07: > I just updated Cython from 3.0a1 to 3.0a2 in one of my projects and > noticed that it seems to introduce issues with private > functions/methods, means methods with leading __. > > I noticed two cases which now fail in my project. I'm however unsure if > thats supposed to happen or if its a problem with the new Cython build. > > > Case 1: private function not declared > > > crash.pxd: > > > cpdef __foo() > > cdef class Bar: > cpdef run(Bar self) > > > crash.pyx: > > > cpdef __foo(): > print("foo") > > cdef class Bar: > cpdef run(Bar self): > __foo() > > print("bar") > > > Running this with the following command: > > py -3 -c "import pyximport;pyximport.install();import > crash;crash.Bar().run()" > > > Result: > > crash.c > C:\Program Files (x86)\Microsoft Visual > Studio\Shared\Python36_64\lib\site-packages\Cython\Compiler\Main.py:344: > FutureWarning: Cython directive 'language_level' not set, using '3str' > for now (Py3). This has changed from earlier releases! File: > D:\crash\crash.pxd > tree = Parsing.p_module(s, pxd, full_module_name) > > Error compiling Cython file: > ------------------------------------------------------------ > ... > cpdef __foo(): > print("foo") > > cdef class Bar: > cpdef run(Bar self): > __foo() > ^ > ------------------------------------------------------------ > > crash.pyx:6:4: undeclared name not builtin: __foo At least this looks like a bug to me. Global module names should not be impacted by this change. > Error compiling Cython file: > ------------------------------------------------------------ > ... > cpdef __foo(): > print("foo") > > cdef class Bar: > cpdef run(Bar self): > __foo() > ^ > ------------------------------------------------------------ > > crash.pyx:6:4: '__foo' redeclared > > Error compiling Cython file: > ------------------------------------------------------------ > ... > cpdef __foo() > ^ > ------------------------------------------------------------ > > crash.pxd:1:12: Previous declaration is here Lovely :) > Another problem, probably related, occurs when trying to override a > private method in a derived class: > > > Case 2: overriding private class methods > > > base.pxd: > > > cdef class Base: > cdef void __foo(Base self) > cpdef run(Base self) > > > base.pyx: > > > cdef class Base: > > cdef void __foo(Base self): > print("foo!") > > cpdef run(Base self): > self.__foo() > > > extend.pxd: > > > from base cimport Base > > cdef class Extend(Base): > pass > > > extend.pyx: > > > cdef class Extend(Base): > > cdef void __foo(Extend self): > print("bar") > > Running with the following command: > > py -3 -c "import pyximport;pyximport.install();import > extend;extend.Extend().run()" > > > Results in the following output: > > > extend.c > C:\Program Files (x86)\Microsoft Visual > Studio\Shared\Python36_64\lib\site-packages\Cython\Compiler\Main.py:344: > FutureWarning: Cython directive 'language_level' not set, using '3str' > for now (Py3). This has changed from earlier releases! File: > D:\crash\extend.pxd > tree = Parsing.p_module(s, pxd, full_module_name) > > Error compiling Cython file: > ------------------------------------------------------------ > ... > cdef class Extend(Base): > > cdef void __foo(Extend self): > ^ > ------------------------------------------------------------ > > extend.pyx:3:7: C method '_Extend__foo' not previously declared in > definition part of extension type 'Extend' This, OTOH, is intended. Private methods are not meant to be inherited and overridden. That's what makes them "private" :) That's consistent with Python semantics. I think it's somewhat up for debate if this should apply in the same way to cdef classes as for Python classes. But from a language design point of view, having this kind of difference between the two seems a bad idea. Do you feel like argueing against this? :) Stefan _______________________________________________ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
