Symbols for Python3 based builds

[Andreas Schneider]

On Thursday, February 21, 2019 11:35:47 AM CET Matthias Klose via samba-
technical wrote:
> Hi,

Hi Matthias,
 
> looking again at building Samba using Python3 for Ubuntu to get Python2
> finally removed from our desktop images.  Looking at the Fedora packaging
> it seems that a combination of
> 
>   samba_version 4.10.0
>   talloc_version 2.1.15
>   tdb_version 1.3.17
>   tevent_version 0.9.38
>   ldb_version 1.5.2
> 
> is built.  However the Fedora packaging doesn't have any checks for symbols
> in shared libraries, and doesn't see what is seen when you use the
> Debian/Ubuntu packaging which is checking that you don't have any symbol
> mismatches without changing the soname.
> 
> Starting with the talloc 2.1.15 tarball, I see
> 
> python2.7 based build:
> 
> libpytalloc-util.so.2 #PACKAGE# #MINVER#
>  PYTALLOC_UTIL_2.0.6 at PYTALLOC_UTIL_2.0.6 2.0.6
>  [...]
> 
> python3.7 based build:
> 
> libpytalloc-util.cpython-37m-x86-64-linux-gnu.so.2 python3-talloc #MINVER#
>  PYTALLOC_UTIL.CPYTHON_37M_X86_64_LINUX_GNU_2.1.15 at PYTALLOC_UTIL.CPYTHON_37M
> _X86_64_LINUX_GNU_2.1.15 2.1.15
> PYTALLOC_UTIL.PY3_2.1.10 at PYTALLOC_UTIL.PY3_2.1.10 2.1.15
> [...]
> 
> so the symbol names add normally just a '.PY3' suffix, but the extra symbol
> and version seems to be unwanted.  There again the specific major Python
> version is encoded (37M), and also the architecture is both encoded in a
> symbol name and version, which makes the library have different symbols on
> different architectures. I have never seen such an explicit encoding in
> other shared libraries. It looks to me that this comes from
> 
>   python3-config --extension-suffix
> 
> This symbol versioning propagates to tdb, ldb, and other libraries.  Maybe
> I'm missing some thing in the configuration of the packages?  Otoh, based
> on discussions with Andrew Bartlet at LinuxConfAU 2018, the intention was
> not to have any encoding of a specific python version or architecture.
> Thoughts?

See the thread at [1] which included patches to fix this.


Best regards,


	Andreas


[1] https://lists.samba.org/archive/samba-technical/2017-September/122897.html


-- 
Andreas Schneider                      asn at samba.org
Samba Team                             www.samba.org
GPG-ID:     8DFF53E18F2ABC8D8F3C92237EE0FC4DCC014E3D