Re: [gentoo-portage-dev] [PATCH] Do not enable optimizations by default to work-around pycparser issue

[Michał Górny]

W dniu sob, 02.09.2017 o godzinie 23∶05 +0200, użytkownik Michał Górny
napisał:
> W dniu sob, 02.09.2017 o godzinie 12∶19 -0700, użytkownik Zac Medico
> napisał:
> > On 09/02/2017 10:46 AM, Michał Górny wrote:
> > > dev-python/pycparser-2.18+ exposes a design flaw in dev-python/ply that
> > > makes it unable to work with -OO code. Remove the optimizations from
> > > Portage shebangs to prevent triggering the issue until we find a proper
> > > solution for it.
> > >
> > > Bug: https://bugs.gentoo.org/628386
> > > ---
> > >  bin/clean_locks   | 2 +-
> > >  bin/dispatch-conf | 2 +-
> > >  bin/ebuild        | 2 +-
> > >  bin/emaint        | 2 +-
> > >  bin/env-update    | 2 +-
> > >  bin/portageq      | 2 +-
> > >  tabcheck.py       | 2 +-
> > >  7 files changed, 7 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/bin/clean_locks b/bin/clean_locks
> > > index 13af06197..fb245972f 100755
> > > --- a/bin/clean_locks
> > > +++ b/bin/clean_locks
> > > @@ -1,4 +1,4 @@
> > > -#!/usr/bin/python -bO
> > > +#!/usr/bin/python -b
> >
> > The diff shows -O, but the commit messages says -OO, so which one is it really?
>
> Yes, it's a curious problem. -OO is the one breaking it but py<3.5 seems
> to be happy to load -OO files with -O:
>
> $ python2.7 -O -c 'import pycparser; print(pycparser.__file__)'
> /usr/lib64/python2.7/site-packages/pycparser/c_parser.py:20: RuntimeWarning: parsing methods must have __doc__ for pycparser to work properly
>   class CParser(PLYParser):
> /usr/lib64/python2.7/site-packages/pycparser/__init__.pyo
>
> $ python3.4 -O -c 'import pycparser; print(pycparser.__cached__)'
> /usr/lib64/python3.4/site-packages/pycparser/c_parser.py:20: RuntimeWarning: parsing methods must have __doc__ for pycparser to work properly
>   class CParser(PLYParser):
> /usr/lib64/python3.4/site-packages/pycparser/__pycache__/__init__.cpython-34.pyo
>
> This doesn't seem to be the case anymore for py3.5+:
>
> $ python3.5 -O -c 'import pycparser; print(pycparser.__cached__)'
> /usr/lib64/python3.5/site-packages/pycparser/__pycache__/__init__.cpython-35.opt-1.pyc

My roundabout thinking here was really silly. I was mistaking -O/-OO for
.pyc/.pyo. For the record, the correct explanation:

Python < 3.5 supports only either -O or -OO, and compiles both levels to
the same .pyo files. So if we compiled the relevant packages with -OO,
then -O implicitly meant -OO.

-- 
Best regards,
Michał Górny