[Pkg-alsa-devel] Bug#1096298: alsa-lib: ftbfs with GCC-15

[Matthias Klose]

Package: src:alsa-lib
Version: 1.2.13-1
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/alsa-lib_1.2.13-1_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

[...]
  313 | static void do_pitchbend(int chan, int lsb, int msb)
      |             ^~~~~~~~~~~~
playmidi1.c:600:21: error: assignment to ‘void (*)(void)’ from incompatible pointer type ‘void (*)(int,  int,  int)’ [-Wincompatible-pointer-types]
  600 |         Mf_pressure = do_pressure;
      |                     ^
playmidi1.c:324:13: note: ‘do_pressure’ declared here
  324 | static void do_pressure(int chan, int pitch, int pressure)
      |             ^~~~~~~~~~~
playmidi1.c:601:25: error: assignment to ‘void (*)(void)’ from incompatible pointer type ‘void (*)(int,  int)’ [-Wincompatible-pointer-types]
  601 |         Mf_chanpressure = do_chanpressure;
      |                         ^
playmidi1.c:335:13: note: ‘do_chanpressure’ declared here
  335 | static void do_chanpressure(int chan, int pressure)
      |             ^~~~~~~~~~~~~~~
playmidi1.c:602:18: error: assignment to ‘void (*)(void)’ from incompatible pointer type ‘void (*)(int,  char *)’ [-Wincompatible-pointer-types]
  602 |         Mf_sysex = do_sysex;
      |                  ^
playmidi1.c:346:13: note: ‘do_sysex’ declared here
  346 | static void do_sysex(int len, char *msg)
      |             ^~~~~~~~
midifile.c: At top level:
midifile.c:137:13: warning: ‘to32bit’ used but never defined
  137 | static long to32bit ();
      |             ^~~~~~~
midifile.c:144:13: warning: ‘metaevent’ used but never defined
  144 | static void metaevent ();
      |             ^~~~~~~~~
midifile.c:515:1: warning: ‘metaevent’ defined but not used [-Wunused-function]
  515 | metaevent (int type)
      | ^~~~~~~~~
make[4]: *** [Makefile:626: playmidi1.o] Error 1
make[4]: *** Waiting for unfinished jobs....
rawmidi.c: In function ‘main’:
rawmidi.c:209:33: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  209 |                                 read(fd_in,&ch,1);
      |                                 ^~~~~~~~~~~~~~~~~
rawmidi.c:234:34: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  234 |                         ch=0x90; write(fd_out,&ch,1);
      |                                  ^~~~~~~~~~~~~~~~~~~
rawmidi.c:235:34: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  235 |                         ch=60;   write(fd_out,&ch,1);
      |                                  ^~~~~~~~~~~~~~~~~~~
rawmidi.c:236:34: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  236 |                         ch=100;  write(fd_out,&ch,1);
      |                                  ^~~~~~~~~~~~~~~~~~~
rawmidi.c:238:34: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  238 |                         ch=0x90; write(fd_out,&ch,1);
      |                                  ^~~~~~~~~~~~~~~~~~~
rawmidi.c:239:34: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  239 |                         ch=60;   write(fd_out,&ch,1);
      |                                  ^~~~~~~~~~~~~~~~~~~
rawmidi.c:240:34: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  240 |                         ch=0;    write(fd_out,&ch,1);
      |                                  ^~~~~~~~~~~~~~~~~~~
rawmidi.c:254:41: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  254 |                                         read(fd_in,&ch,1);
      |                                         ^~~~~~~~~~~~~~~~~
rawmidi.c:265:41: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  265 |                                         write(fd_out,&ch,1);
      |                                         ^~~~~~~~~~~~~~~~~~~
make[4]: Leaving directory '/build/reproducible-path/alsa-lib-1.2.13/test'
make[3]: *** [Makefile:819: check-am] Error 2
make[3]: Leaving directory '/build/reproducible-path/alsa-lib-1.2.13/test'
make[2]: *** [Makefile:669: check-recursive] Error 1
make[2]: Leaving directory '/build/reproducible-path/alsa-lib-1.2.13/test'
make[1]: *** [Makefile:414: check-recursive] Error 1
make[1]: Leaving directory '/build/reproducible-path/alsa-lib-1.2.13'
dh_auto_test: error: make -j8 check "TESTSUITEFLAGS=-j8 --verbose" VERBOSE=1 returned exit code 2
make: *** [debian/rules:13: binary] Error 25
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2