#1133615 qt6-webengine: ftbfs with GCC-16

#1133615#5
Date:
2026-04-13 13:10:20 UTC
From:
To:
Hi,

qt6-webengine fails to build in a test rebuild on at least amd64 and arm64 with
gcc-16/g++-16, but builds properly with gcc-15/g++-15. The severity of this
report will be raised before the forky release.

The full build log can be found at:
https://people.debian.org/~ema/gcc-16-rebuilds/output-1/qt6-webengine_arm64.build.xz

The last lines of the build log are at the end of this report.

To build with GCC 16, either set CC=gcc-16 CXX=g++-16 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t=experimental install g++

Common build failures include unused (but set) variables, array subscripts
partly outside array bounds, and new/dropped symbols in Debian symbols files.
For other C/C++ related build failures see the porting guide at
http://gcc.gnu.org/gcc-16/porting_to.html

Please only close this issue after double-checking that the package can be
built correctly with GCC 16.

Please do not reassign this bug to another package. If a fix in another package
is required, then file a bug for the other package (or clone), and mark this
bug as blocked by the bug in the other package.

[...]


jumbo_build_excluded=["browser"]
jumbo_file_merge_limit=8
ozone_auto_platforms=false
pdf_enable_fontations=false
pdf_enable_v8=false
pdf_enable_xfa=false
pdf_enable_xfa_bmp=false
pdf_enable_xfa_gif=false
pdf_enable_xfa_png=false
pdf_enable_xfa_tiff=false
pdfium_use_qt_libpng=false
pdfium_use_system_libpng=true
pdfium_use_system_libtiff=true
pdfium_use_system_zlib=true
pkg_config="/usr/bin/pkg-config"
qt_freetype_config="/build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/pdf/None/aarch64:qt_freetype_config"
qt_harfbuzz_config="/build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/pdf/None/aarch64:qt_harfbuzz_config"
qt_libjpeg_config="/build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/pdf/None/aarch64:qt_libjpeg_config"
qt_libpng_config="/build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/pdf/None/aarch64:qt_libpng_config"
qtwebengine_target="/build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/pdf/None/aarch64:QtPdf"
strip_absolute_paths_from_debug_symbols=false
treat_warnings_as_errors=false
use_allocator_shim=false
use_cups=false
use_custom_libcxx=false
use_custom_libcxx_for_host=false
use_dawn=false
use_freelist_dispatcher=false
use_gio=false
use_glib=false
use_gold=false
use_jumbo_build=true
use_lld=false
use_ml=false
use_ml_inliner=false
use_mold=false
use_nss_certs=false
use_partition_alloc=true
use_partition_alloc_as_malloc=false
use_qt_freetype=false
use_qt_harfbuzz=false
use_qt_libjpeg=false
use_sysroot=false
use_system_icu=true
use_system_libopenjpeg2=true
use_system_libpng=true
use_system_zlib=true
use_thin_lto=false
use_udev=false
use_v8_context_snapshot=false
use_xkbcommon=false
v8_enable_webassembly=false
v8_symbol_level=0
v8_use_external_startup_data=false
v8_use_external_startup_data=false
webnn_use_tflite=false
-- GN *********************************************************************
WARNING: Support for linking against a C++ standard library other
  than the one in-tree (buildtools/third_party/libc++) is deprecated
  and support for this will end. We plan to remove this option in
  M138.
*********************************************************************
Done. Made 24470 targets from 3553 files in 28389ms
FAILED: [code=1] src/core/None/aarch64/QtWebEngineCore.stamp src/core/None/aarch64/obj/tools/v8_context_snapshot/v8_context_snapshot.stamp src/core/None/aarch64/QtWebEngineCore /build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/core/None/aarch64/QtWebEngineCore.stamp /build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/core/None/aarch64/obj/tools/v8_context_snapshot/v8_context_snapshot.stamp /build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/core/None/aarch64/QtWebEngineCore
cd /build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/core && /usr/bin/ninja -v -C /build/reproducible-path/qt6-webengine-6.10.2+dfsg/obj-aarch64-linux-gnu/src/core/None/aarch64 QtWebEngineCore
ninja: build stopped: subcommand failed.
dh_auto_build: error: cd obj-aarch64-linux-gnu && LC_ALL=C.UTF-8 ninja -j128 -v returned exit code 1
make[1]: *** [debian/rules:81: override_dh_auto_build] Error 25
make[1]: Leaving directory '/build/reproducible-path/qt6-webengine-6.10.2+dfsg'
make: *** [debian/rules:35: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess failed with exit status 2

#1133615#12
Date:
2026-08-17 21:34:46 UTC
From:
To:
We believe that the bug you reported is fixed in the latest version of
qt6-webengine, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1133615@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Patrick Franz <deltaone@debian.org> (supplier of updated qt6-webengine package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Mon, 17 Aug 2026 23:19:54 +0200
Source: qt6-webengine
Architecture: source
Version: 6.10.2+dfsg-5
Distribution: unstable
Urgency: medium
Maintainer: Debian Qt/KDE Maintainers <debian-qt-kde@lists.debian.org>
Changed-By: Patrick Franz <deltaone@debian.org>
Closes: 1133615
Changes:
 qt6-webengine (6.10.2+dfsg-5) unstable; urgency=medium
 .
   [ Patrick Franz ]
   * Add patch to fix build failure with gcc-16 (Closes: #1133615).
Checksums-Sha1:
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 54e4383df7da4d509d72ca1aca82fadf642a7157 347188 qt6-webengine_6.10.2+dfsg-5.debian.tar.xz
 c6bba2aef5b95e37f245e2f226cc836f9fbe645b 13739 qt6-webengine_6.10.2+dfsg-5_source.buildinfo
Checksums-Sha256:
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 277891d8ff54d3633fc4b0765cf75956e08e92c2f2c233dce54e43b534860e1f 347188 qt6-webengine_6.10.2+dfsg-5.debian.tar.xz
 80b07127a0a715289d8db10687ce9fd64d3d38790404d670262416dc1e29887d 13739 qt6-webengine_6.10.2+dfsg-5_source.buildinfo
Files:
 b4d4353aa8e6ddfdb1eee061f8c239dc 5628 libs optional qt6-webengine_6.10.2+dfsg-5.dsc
 2700e5ed16b1221d31cd8b16bfa94b1b 347188 libs optional qt6-webengine_6.10.2+dfsg-5.debian.tar.xz
 8f7c2dc27c4ace70d7672306202487c3 13739 libs optional qt6-webengine_6.10.2+dfsg-5_source.buildinfo
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