Bug#871275: libapt-pkg5.0: requires rebuild against GCC 7 and symbols/shlibs bump
On Mon, Aug 07, 2017 at 03:47:15PM +0100, jcowgill@debian.org wrote:
> Package: libapt-pkg5.0
> Version: 1.5~beta1
> Severity: serious
> Tags: sid buster
> User: debian-gcc@lists.debian.org
> Usertags: gcc-7-op-mangling
>
> Hi,
>
> It appears that your package provides an external symbol that is
> affected by the recent name mangling changes in GCC 7. See:
> https://gcc.gnu.org/gcc-7/porting_to.html#conversion-op-mangling
>
> In GCC 7, the name mangling for C++ conversion operators which return a
> type using the abi_tag attribute (most commonly std::string) has
> changed. When your library is compiled with GCC 7, it will now emit two
> symbols for the conversion operator using the new and old naming.
> Executables compiled with GCC 7 will always use the new symbol, while
> old executables compiled using <= GCC 6 will use the old symbol. For new
> executables to build without undefined references, your library will
> need rebuilding with GCC 7.
I'd say that's a bug in GCC, and it should link to the old name until
GCC 8 is out (and build both) to have a transition period.
>
> To ensure that new executables will pull in the newer version of the
> library built with GCC 7:
> - Your library package should Build-Depend on g++ (>= 4:7).
It's complicated. We also want the package to work in Ubuntu, and that
does not have that yet. For Debian, not doing that works entirely fine,
for Ubuntu it's getting weird down the line and that needs a rebuild
then.
We could just binNMU that, but the next upload is happening any minute
now anyway.
> - If your package provides a symbols file, ensure that the new
> conversion operator symbols have a version matching the version this
> bug is fixed in (including the Debian revision and tilde if
> necessary).
>
> Using apt as an example (debian/libapt-pkg5.0.symbols):
> (c++)"URI::operator std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >[abi:cxx11]()@APTPKG_5.0" 0.8.0
> + (c++)"URI::operator std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >()@APTPKG_5.0" 1.5~beta2~
>
> Where "1.5~beta2" is the version this bug was fixed in.
Sure, we can do that. The symbol file is not up to date
anyway, but missing symbols do not really hurt - they
just mean "latest". Which is better for now.
The next upload will obviously be built with gcc 7, we
can do the extra stuff later on (that's wishlist then
I'd say). So I won't close the bug in the upload and
keep it open until we have the annotations.
--
Debian Developer - deb.li/jak | jak-linux.org - free software dev
| Ubuntu Core Developer |
When replying, only quote what is necessary, and write each reply
directly below the part(s) it pertains to ('inline'). Thank you.
Reply to: