gcc-7 changes appearance of symbols

[Christian Ehrhardt ]

With gcc-7 some of the formerly listed symbols get reported missing.
At the same time others appear.

It turns out they are actually the same (no ABI break).
- (c++)"void std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >::_M_emplace_back_aux<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&>(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)@Base" 2.7.3
- (c++)"void std::vector<std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, std::allocator<std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >::_M_emplace_back_aux<std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >(std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&&)@Base" 2.7.3
+ _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_insertIJRKS5_EEEvN9__gnu_cxx17__normal_iteratorIPS5_S7_EEDpOT_@Base 2.7.4
+ _ZNSt6vectorIS_INSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EESaIS7_EE17_M_realloc_insertIJS7_EEEvN9__gnu_cxx17__normal_iteratorIPS7_S9_EEDpOT_@Base 2.7.4

With c++filt one can translate those new ones and they are in fact the old ones:
$ c++filt _ZNSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS5_EE17_M_realloc_insertIJRKS5_EEEvN9__gnu_cxx17__normal_iteratorIPS5_S7_EEDpOT_
void std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >::_M_realloc_insert<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&>(__gnu_cxx::__normal_iterator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)

But we need to adapt the symbols file to pass shlibs correctly with the new names.

Eventually we need to check with Debian once they move to gcc-7 for default build - did they already or plan they - I'm not sure yet?

[Launchpad Janitor (janitor)]

This bug was fixed in the package nut - 2.7.4-5ubuntu4

---------------
nut (2.7.4-5ubuntu4) artful; urgency=medium

  * d/p/fix-snmp-driver-compile-options.patch: fix cflags/ldflags
    mismatch (LP: #1711092).
  * d/libnutclient0.symbols: fix symbols in regard to gcc-7 (LP: #1711091).

 -- Christian Ehrhardt <email address hidden> Wed, 16 Aug 2017 12:44:26 +0200