On Sun, 2019-10-20 at 07:32 +0300, Matti Picus wrote: > On 19/10/19 11:55 pm, Michał Górny wrote: > > Hello, > > > > I've noticed that the compiled module suffix keeps changing between > > PyPy3 releases: it's been .pypy3-71-*.so for 7.1, now it's .pypy3-72- > > *.so (also .pyc). However, this is a bit surprising to me given that > > for PyPy2 it's still at .pypy-41.so. > > > > Is the bytecode generated by successive PyPy3 releases really > > incompatible between them? Or are the suffix changes only incidental? > > They cause quite some trouble for us, since they make it necessary to > > recompile installed modules on Gentoo, and PyPy's overzealous compiling > > causes access violations for our users. > > > > TIA for any help. > For c-extensions the major-minor version becomes the PEP 425 ABI tag > https://www.python.org/dev/peps/pep-0425/#abi-tag. My operating > assumption is that any change in the ABI requires a change in that > field. Our support for the massive CPython C-API changes between > versions, which changes the ABI. In particular, between 7.1 and 7.2 the > PyDateTime_CAPI structure size changed, and we changed the order of > fields in Py_Buffer, as well as adding many missing functions and > macros. The complete log is here > http://doc.pypy.org/en/latest/release-v7.2.0.html#c-api-cpyext-and-c-extensions > > for both versions and here > http://doc.pypy.org/en/latest/release-v7.2.0.html#python-3-6-c-api for > the pypy3.6 specific ones. > > > The fact that the PyPy2 ABI tag did **not** change is most likely a bug > in the release process. I think there will be cases where pypy2-v7.1.1 > and pypy2-v7.2.0 c-extension modules will be slightly incompatible with > eachother, although a cursory test of mixing NumPy across versions > (building on 7.2, copying into 7.1) seems to pass "np.test()". Perhaps a > better test would be to mix the pygolang c-extension modules, which seem > to stress-test the C-API more extensively given the number of issues it > exposes.
Thanks for the explanation. This answers my question. Do you need me to file a bug for the ABI tag not changing in PyPy2, or will you take it from here? > The pyc files should always be rebuilt in each python environment, so I > am not sure what problems could be caused by bumping the ABI tag. Does > Gentoo somehow mix the byte-compiled pyc files across versions? > > > I am not sure what you mean by "compiling causes access violations for > our users", could you point to a discussion of the problem? > It's related to circular dependencies between packages. For example, when rebuild setuptools for the new version, it tries to load its plugins and byte-compile them as well. Since they don't belong to the setuptools package, our PM catches that as illegal access. It's a generic problem with Python, not something you need to worry about. I've just been pointed out that we already have a hack for it, I just need to add PyPy3 to it. -- Best regards, Michał Górny
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