[Pkg-samba-maint] debian-only patches break upgrading our python3 bindings (was: Re: Bug#814928: build python3 bindings)

[Jelmer Vernooij]

On Mon, Apr 04, 2016 at 08:26:51AM +1200, Andrew Bartlett wrote:
> On Mon, 2016-04-04 at 07:33 +1200, Andrew Bartlett wrote:
> > On Sun, 2016-04-03 at 13:24 +0000, Jelmer Vernooij wrote:
> > > On Mon, Apr 04, 2016 at 12:51:00AM +1200, Andrew Bartlett wrote:
> > > > On Tue, 2016-02-16 at 18:10 +0100, Matthias Klose wrote:
> > > > > Package: src:talloc
> > > > > Version: 2.1.5-1
> > > > > Tags: patch
> > > > > 
> > > > > This is a first shot of building python3 bindings for talloc
> > > > > (to
> > > > > be
> > > > > followed up 
> > > > > by ldb and tdb bindings).  The packaging certainly can be
> > > > > improved,
> > > > > making it 
> > > > > more robust for version changes. however there is one change
> > > > > which
> > > > > should be 
> > > > > applied upstream: The library *name* for the helper library
> > > > > includes
> > > > > the whole 
> > > > > SOABI name for a python extension, including the multiarch name
> > > > > in
> > > > > Python 3.5. 
> > > > > This leads to different sonames on different architectures.
> > > > > Maybe
> > > > > this should be 
> > > > > fixed so that distros rely on a common name for python3 builds.
> > > > 
> > > > How important is this? 
> > > > 
> > > > I ask because it is causing chaos now that we have added new
> > > > functions
> > > > to the pytalloc-util library.  If we had built with developer
> > > > mode,
> > > > we
> > > > would have noticed it totally breaking the ABI checking, but as
> > > > it
> > > > is,
> > > > we only noticed when upstream (me) added new functions.  (That
> > > > triggered the symbols checker in our packaging process.)
> > > > 
> > > > It causes an empty (essentially) vscript to be written, meaning
> > > > all
> > > > symbols are regarded as new each release, because other parts of
> > > > the
> > > > code expected the previous name.
> > > > 
> > > > https://git.samba.org/?p=samba.git;a=commitdiff;h=9ef47d253179472
> > > > 48
> > > > b079
> > > > 6059e6f0a851ba3cb07
> > > > 
> > > > For the changes symbols, see 
> > > > https://git.samba.org/abartlet/talloc-debi
> > > > an.git/?p=abartlet/talloc-debian.git;a=blobdiff;f=debian/python3
> > > > -talloc.symbols;h=00fd4296d269ffc6acebeee2c9cb85be8a789813;hp=8bc
> > > > 5b
> > > > 8487
> > > > b809160757bb69f743f282a9e49654b;hb=fa48dc43b7e48662879c0cddaa65ef
> > > > de
> > > > 7444
> > > > 3b6b;hpb=e64cd98c001e05b9c7311b49df010784b25313ae
> > > > 
> > > > I would prefer to drop this from the package until an acceptable
> > > > solution is found upstream.  I've tried changing the
> > > > SAMBA_LIBRARY
> > > > code
> > > > to match, but I still get .py3 and -py3 mixups.  As Fedora is
> > > > happy
> > > > to
> > > > keep the cpython* part of the .so name, I propose we do the same.
> > > >  It
> > > > is Red Hat staff who have been leading the python3 work, I would
> > > > rather
> > > > follow them if possible:
> > > > 
> > > > http://pkgs.fedoraproject.org/cgit/rpms/libtalloc.git/tree/libtal
> > > > lo
> > > > c.sp
> > > > ec#n135
> > > > 
> > > > It should be safe to revert this in unstable, nobody seems to be
> > > > using
> > > > this yet.
> > > 
> > > How about we for the moment:
> > > 
> > >  * upload a package to experimental that keeps the python3 support
> > > in
> > >    talloc
> > >  * remove python3 support in talloc in unstable
> > > 
> > > Then we can work out how to name the symbols, without obstructing
> > > any
> > > of the work for the security release and without risking that the
> > > incorrect symbol names end up in a Debian or Ubuntu release.
> > 
> > Sounds good.
> 
> I've uploaded patches to my repo to do exactly this (master removes
> python3, experimental just removes the SOABI fix and has the new
> version that breaks unpatched Samba < 4.4.0 (and is needed for 4.4).
> Let me know what you think.

Mostly LGTM. Please add a dot after each sentence in the changelogs.

I don't think it's fair to say that reverting the symbols patch is
breaking the symbols. The symbols are broken by design as they include
the upstream version string, meaning each new version will change the
names of all symbols:

E.g.:

+ pytalloc_reference_ex at PYTALLOC_UTIL.PY3_2.1.5 2.1.6

(notice the _2.1.5 at the end of the symbol name)

Cheers,

Jelmer
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