Bug#1097959: swt4-gtk: ftbfs with GCC-15

[Matthias Klose]

Package: src:swt4-gtk
Version: 4.29.0-1
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/swt4-gtk_4.29.0-1_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

[...]
      |                                ^
os_structs.c:51:27: error: assignment to ‘void (*)(GObject *)’ {aka ‘void (*)(struct _GObject *)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
   51 |         lpStruct->dispose = (void (*)())(*env)->GetLongField(env, lpObject, GObjectClassFc.dispose);
      |                           ^
os_structs.c:52:28: error: assignment to ‘void (*)(GObject *)’ {aka ‘void (*)(struct _GObject *)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
   52 |         lpStruct->finalize = (void (*)())(*env)->GetLongField(env, lpObject, GObjectClassFc.finalize);
      |                            ^
os_structs.c:53:47: error: assignment to ‘void (*)(GObject *, guint,  GParamSpec **)’ {aka ‘void (*)(struct _GObject *, unsigned int,  struct _GParamSpec **)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
   53 |         lpStruct->dispatch_properties_changed = (void (*)())(*env)->GetLongField(env, lpObject, GObjectClassFc.dispatch_properties_changed);
      |                                               ^
os_structs.c:54:26: error: assignment to ‘void (*)(GObject *, GParamSpec *)’ {aka ‘void (*)(struct _GObject *, struct _GParamSpec *)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
   54 |         lpStruct->notify = (void (*)())(*env)->GetLongField(env, lpObject, GObjectClassFc.notify);
      |                          ^
os_structs.c: In function ‘getGtkCellRendererClassFields’:
os_structs.c:349:26: error: assignment to ‘void (*)(GtkCellRenderer *, cairo_t *, GtkWidget *, const GdkRectangle *, const GdkRectangle *, GtkCellRendererState)’ {aka ‘void (*)(struct _GtkCellRenderer *, struct _cairo *, struct _GtkWidget *, const struct _cairo_rectangle_int *, const struct _cairo_rectangle_int *, GtkCellRendererState)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
  349 |         lpStruct->render = (void(*)())(*env)->GetLongField(env, lpObject, GtkCellRendererClassFc.render);
      |                          ^
os_structs.c:354:39: error: assignment to ‘void (*)(GtkCellRenderer *, GtkWidget *, gint *, gint *)’ {aka ‘void (*)(struct _GtkCellRenderer *, struct _GtkWidget *, int *, int *)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
  354 |         lpStruct->get_preferred_width = (void(*)())(*env)->GetLongField(env, lpObject, GtkCellRendererClassFc.get_preferred_width);
      |                                       ^
os_structs.c: In function ‘getGtkWidgetClassFields’:
os_structs.c:429:23: error: assignment to ‘void (*)(GtkWidget *)’ {aka ‘void (*)(struct _GtkWidget *)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
  429 |         lpStruct->map = (void(*)())(*env)->GetLongField(env, lpObject, GtkWidgetClassFc.map);
      |                       ^
os_structs.c:430:33: error: assignment to ‘void (*)(GtkWidget *, GtkAllocation *)’ {aka ‘void (*)(struct _GtkWidget *, struct _cairo_rectangle_int *)’} from incompatible pointer type ‘void (*)(void)’ [-Wincompatible-pointer-types]
  430 |         lpStruct->size_allocate = (void(*)())(*env)->GetLongField(env, lpObject, GtkWidgetClassFc.size_allocate);
      |                                 ^
make[2]: *** [make_linux.mak:151: os_structs.o] Error 1
os.c: In function ‘Java_org_eclipse_swt_internal_gtk_OS_Call__JJII’:
os.c:10106:21: error: too many arguments to function ‘(jint (*)(void))arg0’; expected 0, have 3
10106 |         rc = (jint)((jint (*)())arg0)(arg1, arg2, arg3);
      |                    ~^~~~~~~~~~~~~~~~~ ~~~~
os.c: In function ‘Java_org_eclipse_swt_internal_gtk_OS_Call__JJJ’:
os.c:10118:21: error: too many arguments to function ‘(jint (*)(void))arg0’; expected 0, have 2
10118 |         rc = (jint)((jint (*)())arg0)(arg1, arg2);
      |                    ~^~~~~~~~~~~~~~~~~ ~~~~
os.c: In function ‘Java_org_eclipse_swt_internal_gtk_OS_XCheckIfEvent’:
os.c:10512:71: error: passing argument 3 of ‘XCheckIfEvent’ from incompatible pointer type [-Wincompatible-pointer-types]
10512 |         rc = (jboolean)XCheckIfEvent((Display *)arg0, (XEvent *)arg1, (Bool (*)())arg2, (XPointer)arg3);
      |                                                                       ^~~~~~~~~~~~~~~~
      |                                                                       |
      |                                                                       int (*)(void)
In file included from /usr/include/gtk-3.0/gdk/gdkx.h:30,
                 from /usr/include/gtk-3.0/gtk/gtksocket.h:34,
                 from /usr/include/gtk-3.0/gtk/gtkx.h:29,
                 from os.h:60,
                 from os_structs.h:19,
                 from os.c:20:
/usr/include/X11/Xlib.h:2105:5: note: expected ‘int (*)(Display *, XEvent *, char *)’ but argument is of type ‘int (*)(void)’
 2105 |     Bool (*) (
      |     ^
os.c: In function ‘Java_org_eclipse_swt_internal_gtk_OS_call__JJJJJ’:
os.c:10724:22: error: too many arguments to function ‘(jlong (*)(void))arg0’; expected 0, have 4
10724 |         rc = (jlong)((jlong (*)())arg0)(arg1, arg2, arg3, arg4);
      |                     ~^~~~~~~~~~~~~~~~~~ ~~~~
os.c: In function ‘Java_org_eclipse_swt_internal_gtk_OS_call__JJJJJJJ’:
os.c:10736:22: error: too many arguments to function ‘(jlong (*)(void))arg0’; expected 0, have 6
10736 |         rc = (jlong)((jlong (*)())arg0)(arg1, arg2, arg3, arg4, arg5, arg6);
      |                     ~^~~~~~~~~~~~~~~~~~ ~~~~
os.c: In function ‘Java_org_eclipse_swt_internal_gtk_OS_call__JJJJJJJJ’:
os.c:10748:22: error: too many arguments to function ‘(jlong (*)(void))arg0’; expected 0, have 7
10748 |         rc = (jlong)((jlong (*)())arg0)(arg1, arg2, arg3, arg4, arg5, arg6, arg7);
      |                     ~^~~~~~~~~~~~~~~~~~ ~~~~
make[2]: *** [make_linux.mak:149: os.o] Error 1
make[2]: Leaving directory '/build/reproducible-path/swt4-gtk-4.29.0/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library'
dh_auto_build: error: make -j8 "INSTALL=install --strip-program=true" -C "bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library" "-I../../../Eclipse SWT/common/library/" -f make_linux.mak make_atk make_awt make_cairo make_glx make_swt make_webkit make_swtpi returned exit code 2
make[1]: *** [debian/rules:37: override_dh_auto_build] Error 25
make[1]: Leaving directory '/build/reproducible-path/swt4-gtk-4.29.0'
make: *** [debian/rules:27: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2