[Pkg-libvirt-maintainers] Bug#909417: gtk-vnc: FTBFS randomly (vncconnectiontest fails with "assertion failed")

[Santiago Vila]

Package: src:gtk-vnc
Version: 0.6.0-3
Severity: serious
Tags: ftbfs

Dear maintainer:

I tried to build this package in buster but it failed:

--------------------------------------------------------------------------------
[...]
 debian/rules build-arch
dh build-arch --with autoreconf
   dh_update_autotools_config -a
   dh_autoreconf -a
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
libtoolize: copying file 'build-aux/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'm4'.
libtoolize: copying file 'm4/libtool.m4'
libtoolize: copying file 'm4/ltoptions.m4'
libtoolize: copying file 'm4/ltsugar.m4'
libtoolize: copying file 'm4/ltversion.m4'
libtoolize: copying file 'm4/lt~obsolete.m4'
configure.ac:14: installing 'build-aux/compile'
configure.ac:11: installing 'build-aux/missing'

[... snipped ...]

# FAIL:  1
# XPASS: 0
# ERROR: 0

.. contents:: :depth: 2

FAIL: vncconnectiontest
=======================

/conn/validation/rre: OK
/conn/validation/copyrect: OK
/conn/validation/hextile: OK
/conn/validation/unexpectedcmap: **
ERROR:../../../src/vncconnectiontest.c:62:test_send_u16: assertion failed: (g_output_stream_write_all(os, &v, 2, NULL, NULL, NULL))
FAIL vncconnectiontest (exit status: 134)

============================================================================
Testsuite summary for gtk-vnc 0.9.0
============================================================================
# TOTAL: 1
# PASS:  0
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0
============================================================================
See src/test-suite.log
Please report to https://gitlab.gnome.org/GNOME/gtk-vnc/issues
============================================================================
make[6]: *** [Makefile:1697: test-suite.log] Error 1
make[6]: Leaving directory '/<<PKGBUILDDIR>>/build/gtk2/src'
make[5]: *** [Makefile:1805: check-TESTS] Error 2
make[5]: Leaving directory '/<<PKGBUILDDIR>>/build/gtk2/src'
make[4]: *** [Makefile:1878: check-am] Error 2
make[4]: Leaving directory '/<<PKGBUILDDIR>>/build/gtk2/src'
make[3]: *** [Makefile:1880: check] Error 2
make[3]: Leaving directory '/<<PKGBUILDDIR>>/build/gtk2/src'
make[2]: *** [Makefile:624: check-recursive] Error 1
make[2]: Leaving directory '/<<PKGBUILDDIR>>/build/gtk2'
dh_auto_test: cd build/gtk2 && make -j1 check VERBOSE=1 returned exit code 2
make[1]: *** [debian/rules:33: override_dh_auto_test] Error 2
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:6: build-arch] Error 2
dpkg-buildpackage: error: debian/rules build-arch subprocess returned exit status 2
--------------------------------------------------------------------------------

I'm reporting this as serious because it happens on the buildds:

https://buildd.debian.org/status/fetch.php?pkg=gtk-vnc&arch=amd64&ver=0.6.0-3&stamp=1486745781&raw=0

The above error was from stretch, but it's the same error I get on buster and sid,
which means the bug has not been fixed yet.

If you could not reproduce this on a single-CPU machine using sbuild (as I do),
where this failure seems to be particularly easy to trigger, please say so
and I will gladly offer ssh access to a machine where this happens
(contact me privately for details).

Thanks.