Bug#1098122: xboard: ftbfs with GCC-15

[Matthias Klose]

Package: src:xboard
Version: 4.9.1-3
Severity: important
Tags: sid forky
User: debian-gcc at lists.debian.org
Usertags: ftbfs-gcc-15

[This bug is NOT targeted to the upcoming trixie release]

Please keep this issue open in the bug tracker for the package it
was filed for.  If a fix in another package is required, please
file a bug for the other package (or clone), and add a block in this
package. Please keep the issue open until the package can be built in
a follow-up test rebuild.

The package fails to build in a test rebuild on at least amd64 with
gcc-15/g++-15, but succeeds to build with gcc-14/g++-14. The
severity of this report will be raised before the forky release.

The full build log can be found at:
http://qa-logs.debian.net/2025/02/16/amd64exp/xboard_4.9.1-3_unstable_gccexp.log.gz
The last lines of the build log are at the end of this report.

To build with GCC 15, either set CC=gcc-15 CXX=g++-15 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t=experimental install g++ 

GCC 15 now defaults to the C23/C++23 standards, exposing many FTBFS.
Other Common build failures are new warnings resulting in build failures
with -Werror turned on, or new/dropped symbols in Debian symbols files.
For other C/C++ related build failures see the porting guide at
http://gcc.gnu.org/gcc-15/porting_to.html

[...]
      |                                                         ^~~~~~~~~~~
In function ‘snprintf’,
    inlined from ‘read_from_ics’ at backend.c:3136:10:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:68:10: note: ‘__builtin___snprintf_chk’ output between 12 and 20522 bytes into a destination of size 512
   68 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |                                    __glibc_objsize (__s), __fmt,
      |                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |                                    __va_arg_pack ());
      |                                    ~~~~~~~~~~~~~~~~~
backend.c: In function ‘read_from_ics’:
backend.c:3095:52: warning: ‘%s’ directive output may be truncated writing up to 19999 bytes into a region of size between 1 and 512 [-Wformat-truncation=]
 3095 |                         snprintf(mess, MSG_SIZ, "%s%s", talker, parse);
      |                                                    ^~           ~~~~~
In function ‘snprintf’,
    inlined from ‘read_from_ics’ at backend.c:3095:4:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:68:10: note: ‘__builtin___snprintf_chk’ output between 1 and 20511 bytes into a destination of size 512
   68 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |                                    __glibc_objsize (__s), __fmt,
      |                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |                                    __va_arg_pack ());
      |                                    ~~~~~~~~~~~~~~~~~
backend.c: In function ‘read_from_ics’:
backend.c:3101:62: warning: ‘%s’ directive output may be truncated writing up to 19999 bytes into a region of size 510 [-Wformat-truncation=]
 3101 |                                 snprintf(mess, MSG_SIZ, "%s: %s", chatPartner[chattingPartner], parse);
      |                                                              ^~                                 ~~~~~
In function ‘snprintf’,
    inlined from ‘read_from_ics’ at backend.c:3101:5:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:68:10: note: ‘__builtin___snprintf_chk’ output 3 or more bytes (assuming 20002) into a destination of size 512
   68 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |                                    __glibc_objsize (__s), __fmt,
      |                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |                                    __va_arg_pack ());
      |                                    ~~~~~~~~~~~~~~~~~
backend.c: In function ‘read_from_ics’:
backend.c:3201:48: warning: ‘__builtin___snprintf_chk’ output may be truncated before the last format character [-Wformat-truncation=]
 3201 |               snprintf(buf, sizeof(buf), "%s@%s", ics_handle, appData.icsHost);
      |                                                ^
In function ‘snprintf’,
    inlined from ‘read_from_ics’ at backend.c:3201:8:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:68:10: note: ‘__builtin___snprintf_chk’ output 2 or more bytes (assuming 513) into a destination of size 512
   68 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |                                    __glibc_objsize (__s), __fmt,
      |                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |                                    __va_arg_pack ());
      |                                    ~~~~~~~~~~~~~~~~~
backend.c: In function ‘read_from_ics’:
backend.c:3704:48: warning: ‘%s’ directive output may be truncated writing up to 511 bytes into a region of size 507 [-Wformat-truncation=]
 3704 |                 snprintf(str, MSG_SIZ, "ICS %s %s match", star_match[0], star_match[1]);
      |                                                ^~                        ~~~~~~~~~~~~~
In function ‘snprintf’,
    inlined from ‘read_from_ics’ at backend.c:3704:3:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:68:10: note: ‘__builtin___snprintf_chk’ output 12 or more bytes (assuming 523) into a destination of size 512
   68 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |                                    __glibc_objsize (__s), __fmt,
      |                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |                                    __va_arg_pack ());
      |                                    ~~~~~~~~~~~~~~~~~
make[3]: Leaving directory '/build/reproducible-path/xboard-4.9.1'
make[2]: *** [Makefile:1175: all-recursive] Error 1
make[2]: Leaving directory '/build/reproducible-path/xboard-4.9.1'
make[1]: *** [Makefile:679: all] Error 2
make[1]: Leaving directory '/build/reproducible-path/xboard-4.9.1'
dh_auto_build: error: make -j8 returned exit code 2
make: *** [debian/rules:6: binary] Error 25
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2