Is this why I can only make scipy.spatial.cKDTree support pickle on Python 3? Since scipy.spatial.cKDTree comes from a relative import of .ckdtree.cKDTree into scipy.spatial, it somehow works on Python 3 but fails on Python 2.
Sturla Nathaniel Smith <n...@vorpus.org> wrote: > On Mar 14, 2015 2:03 PM, "Robert Bradshaw" > <rober...@gmail.com> wrote: >> >> That is strange, looks like it was an attempt to support relative imports? >> >> https://github.com/cython/cython/blob/384cc660f5c7958524b8839ba24099fdbc6eaffd/Cython/Compiler/ModuleNode.py#L2271 > > Ah, I see. > > I don't see how this could affect relative imports, because if foo.bar > does 'import .baz', this doesn't actually trigger any access to > sys.modules["foo.bar"]. (Exception: if you have foo/__init__.pyx. Is > that actually supported?) The critical thing for relative imports is > having correct __name__ and/or __package__ module-level global > variables, and AFAICT cython is not currently doing anything to set > these up. But it probably should, because relative imports are a > thing. > > OTOH, putting the module into sys.modules *is* crucial to handle > recursive imports, i.e. where foo.pyx's module init function imports > bar.py, and bar.py imports foo. For regular python modules or for > python 2 extension modules, this works because even while foo is still > initializing, you can already get its (incomplete) module object from > sys.modules; for python 3 extension modules this won't work unless we > do it by hand. So the code that Cython is generating seems to be > correct and necessary, it just has the wrong idea about what the > fully-qualified module name is, and this breaks things. > > So I'm convinced that Cython has to know the fully-qualified module > name for correct operation, and if it's wrong then weird real bugs > will happen. Next question: how am I supposed to make this work? Maybe > I'm just missing it, but I can't find anything in the docs about how I > should tell cython that mtrand.pyx is really numpy.random.mtrand...? > > -n > >> On Sat, Mar 14, 2015 at 1:17 AM, Nathaniel Smith >> <n...@vorpus.org> wrote: >>> Hi all, >>> >>> Can anyone shed any light on this? >>> >>> https://github.com/numpy/numpy/issues/5680 >>> >>> -n >>> >>> -- >>> Nathaniel J. Smith -- http://vorpus.org >>> _______________________________________________ >>> cython-devel mailing list >>> cython-devel@python.org >>> https://mail.python.org/mailman/listinfo/cython-devel >> _______________________________________________ >> cython-devel mailing list >> cython-devel@python.org >> https://mail.python.org/mailman/listinfo/cython-devel _______________________________________________ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
