Bug#1097292: libyaml-syck-perl: ftbfs with GCC-15

[Matthias Klose]

Package: src:libyaml-syck-perl
Version: 1.34-2
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/libyaml-syck-perl_1.34-2_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

[...]
   69 | #define do_hash(key,table) (unsigned int)(*(table)->type->hash)((key))
      |                                          ~^~~~~~~~~~~~~~~~~~~~~ ~~~~~
syck_st.c:70:33: note: in expansion of macro ‘do_hash’
   70 | #define do_hash_bin(key,table) (do_hash(key, table)%(table)->num_bins)
      |                                 ^~~~~~~
syck_st.c:442:16: note: in expansion of macro ‘do_hash_bin’
  442 |     hash_val = do_hash_bin(*key, table);
      |                ^~~~~~~~~~~
syck_st.h:13:11: note: declared here
   13 |     int (*hash)();
      |           ^~~~
syck_st.c:67:40: error: too many arguments to function ‘table->type->compare’; expected 0, have 2
   67 | #define EQUAL(table,x,y) ((x)==(y) || (*table->type->compare)((x),(y)) == 0)
      |                                       ~^~~~~~~~~~~~~~~~~~~~~~ ~~~
syck_st.c:451:36: note: in expansion of macro ‘EQUAL’
  451 |         if ((ptr->key != never) && EQUAL(table, ptr->key, *key)) {
      |                                    ^~~~~
syck_st.h:12:11: note: declared here
   12 |     int (*compare)();
      |           ^~~~~~~
syck_st.c: In function ‘delete_never’:
syck_st.c:464:1: warning: old-style function definition [-Wold-style-definition]
  464 | delete_never(key, value, never)
      | ^~~~~~~~~~~~
syck_st.c: In function ‘st_cleanup_safe’:
syck_st.c:472:1: warning: old-style function definition [-Wold-style-definition]
  472 | st_cleanup_safe(table, never)
      | ^~~~~~~~~~~~~~~
syck_st.c:475:1: error: number of arguments doesn’t match prototype
  475 | {
      | ^
syck_st.h:35:54: error: prototype declaration
   35 | void st_foreach(), st_add_direct(), st_free_table(), st_cleanup_safe();
      |                                                      ^~~~~~~~~~~~~~~
syck_st.c:478:5: error: too many arguments to function ‘st_foreach’; expected 0, have 3
  478 |     st_foreach(table, (enum st_retval (*)())delete_never, never);
      |     ^~~~~~~~~~ ~~~~~
syck_st.h:35:6: note: declared here
   35 | void st_foreach(), st_add_direct(), st_free_table(), st_cleanup_safe();
      |      ^~~~~~~~~~
syck_st.c: In function ‘st_foreach’:
syck_st.c:483:1: warning: old-style function definition [-Wold-style-definition]
  483 | st_foreach(table, func, arg)
      | ^~~~~~~~~~
syck_st.c:487:1: error: number of arguments doesn’t match prototype
  487 | {
      | ^
syck_st.h:35:6: error: prototype declaration
   35 | void st_foreach(), st_add_direct(), st_free_table(), st_cleanup_safe();
      |      ^~~~~~~~~~
syck_st.c:495:23: error: too many arguments to function ‘func’; expected 0, have 3
  495 |             retval = (*func)(ptr->key, ptr->record, arg);
      |                      ~^~~~~~ ~~~~~~~~
syck_st.c: In function ‘strhash’:
syck_st.c:520:1: warning: old-style function definition [-Wold-style-definition]
  520 | strhash(string)
      | ^~~~~~~
syck_st.c: In function ‘numcmp’:
syck_st.c:566:1: warning: old-style function definition [-Wold-style-definition]
  566 | numcmp(x, y)
      | ^~~~~~
syck_st.c: In function ‘numhash’:
syck_st.c:573:1: warning: old-style function definition [-Wold-style-definition]
  573 | numhash(n)
      | ^~~~~~~
make[1]: *** [Makefile:371: syck_st.o] Error 1
make[1]: Leaving directory '/build/reproducible-path/libyaml-syck-perl-1.34'
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